A low-barrier hydrogen bond in the catalytic triad of serine proteases? Theory versus experiment

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usa-input-error-message selection-validation-message"> Name must be less than 100 characters </div> </div> <div class="action-panel-control-wrap existing-collections-controls"> <label for="collections-action-panel-add-to-existing" class="action-panel-label"> Choose a collection: </label> <select id="collections-action-panel-add-to-existing" class="action-panel-selector collections-action-add-to-existing" data-ga-category="save_share" data-ga-action="select_collection" data-ga-label="($('#collections-action-add-to-existing').val() === 'Favorites') ? 'Favorites' : 'non_favorites_collection'"> </select> <div class="collections-retry-load-on-error usa-input-error-message selection-validation-message"> Unable to load your collection due to an error<br> <a href="#">Please try again</a> </div> </div> </div> <div class="action-panel-actions"> <button class="action-panel-submit" type="submit" data-loading-label="Adding..." data-pinger-ignore data-ga-category="save_share" data-ga-action="collections" data-ga-label="add"> Add </button> <button class="action-panel-cancel" aria-label="Close 'Add to Collections' panel" ref="linksrc=close_collections_panel" aria-controls="collections-action-panel" aria-expanded="false" data-ga-category="save_share" data-ga-action="collections" data-ga-label="cancel"> Cancel </button> </div> </form> </div> </div> <div id="bibliography-action-panel" class="bibliography-action-panel action-panel in-progress-dots-panel" aria-hidden="true" data-bibliography-open-panel-enabled="false" data-bibliography-open-panel-url-hash="#open-bibliography-panel"> <div class="inner-wrap"> <h3 class="action-panel-heading"> Add to My Bibliography </h3> <form id="bibliography-action-panel-form" class="bibliography-action-panel-form action-panel-content action-form action-panel-smaller-selectors" data-add-to-bibliography-max-amount="100" data-add-to-bibliography-batch-size="10" data-bibliography-delegates-url="/list-bibliography-delegates/" data-add-to-bibliography-url="/add-to-bibliography/" data-get-article-ids-by-search-url="/get-article-ids-by-search/" data-mybib-root-url="https://www.ncbi.nlm.nih.gov/myncbi/collections/mybibliography/"> <input type="hidden" name="csrfmiddlewaretoken" value="Vdaq4aVLxIvFLjtwgj9nOiXCOXVjq2t2XiUDRuuP6zRgFizqsR8Sy88xKr9K6F9b"> <div class="action-panel-control-wrap bibliographies-controls"> <div class="choice-group"> <ul class="bibliographies-action-add radio-group-items"> <li> <input name="bibliography" id="my-bibliography" class="my-bibliography" type="radio" checked/> <label for="my-bibliography">My Bibliography</label> </li> </ul> </div> </div> <div class="bibliographies-retry-load-on-error usa-input-error-message selection-validation-message"> Unable to load your delegates due to an error<br> <a href="#">Please try again</a> </div> <div class="action-panel-actions"> <button class="action-panel-submit" type="submit" data-loading-label="Adding..." data-pinger-ignore> Add </button> <button class="action-panel-cancel" aria-label="Close 'Add to bibliography' panel" ref="linksrc=close_bibliography_panel" aria-controls="bibliography-action-panel" aria-expanded="false" data-ga-category="save_share" data-ga-action="mybib" data-ga-label="cancel"> Cancel </button> </div> </form> </div> </div> <div id="saved-search-action-panel" class="saved-search-action-panel action-panel " aria-hidden="true" data-saved-search-open-panel-enabled="false" data-saved-search-open-panel-url-hash="#open-saved-search-panel"> <div class="inner-wrap"> <h2 class="action-panel-heading"> Your saved search </h2> <form id="saved-search-action-panel-form" class="saved-search-action-panel-form action-panel-content action-form" data-create-saved-search-url="/create-saved-search/" data-try-search-terms-url="/try-search-term/" data-saved-search-root-url="https://www.ncbi.nlm.nih.gov/myncbi/searches/"> <input type="hidden" name="csrfmiddlewaretoken" value="Vdaq4aVLxIvFLjtwgj9nOiXCOXVjq2t2XiUDRuuP6zRgFizqsR8Sy88xKr9K6F9b"> <div class="action-panel-control-wrap"> <label for="saved-search-name" class="action-panel-label saved-search-name-label required-field-asterisk"> Name of saved search: </label> <input maxlength="200" type="text" name="saved-search-name" id="saved-search-name" class="saved-search-name" value="" required pattern="[^"&=<>\/]*" title="The following characters are not allowed in the Name field: "&=<>/"> </div> <div class="action-panel-control-wrap"> <label for="saved-search-term" class="action-panel-label required-field-asterisk"> Search terms: </label> <textarea name="saved-search-term" id="saved-search-term" class="saved-search-term" required></textarea> </div> <div class="test-search-term-wrap"> <a href="#" class="try-search-term">Test search terms</a> </div> <div class="choice-group action-panel-extra-margin-top"> <span class="action-panel-label" id="fieldset-label"> Would you like email updates of new search results? </span> <fieldset id="saved-search-alert" aria-describedby="fieldset-label"> <legend class="usa-sr-only">Saved Search Alert Radio Buttons</legend> <ul class="radio-group-items"> <li> <input type="radio" id="saved-search-alert-yes" class="saved-search-alert-yes" name="saved-search-alert" value="yes" checked> <label for="saved-search-alert-yes" class="action-panel-label">Yes</label> </li> <li> <input aria-label="No radio input" type="radio" id="saved-search-alert-no" class="saved-search-alert-no" name="saved-search-alert" value="no"> <label for="saved-search-alert-no" class="action-panel-label">No</label> </li> </ul> </fieldset> </div> <div class="alert-schedule-wrap"> <div class="action-panel-control-wrap"> <label class="action-panel-label"> Email: </label> <span aria-label="Email address" id="saved-search-email" class="action-panel-label"><span class="action-panel-label-bold"></span> (<a class="myncbi-account-settings" href="https://www.ncbi.nlm.nih.gov/account/settings/">change</a>)</span> </div> <div class="action-panel-control-wrap action-panel-extra-margin-top"> <label for="saved-search-frequency" class="action-panel-label"> Frequency: </label> <select id="saved-search-frequency" class="no-border-panel-selector saved-search-frequency"> <option value="monthly">Monthly</option> <option value="weekly">Weekly</option> <option value="daily">Daily</option> </select> </div> <div class="action-panel-control-wrap saved-search-monthly-additional"> <label for="saved-search-monthly-on-day" class="action-panel-label"> Which day? </label> <select id="saved-search-monthly-on-day" class="no-border-panel-selector"> <option value="Sunday">The first Sunday</option> <option value="Monday">The first Monday</option> <option value="Tuesday">The first Tuesday</option> <option value="Wednesday">The first Wednesday</option> <option value="Thursday">The first Thursday</option> <option value="Friday">The first Friday</option> <option value="Saturday">The first Saturday</option> <option value="day">The first day</option> <option value="weekday">The first weekday</option> </select> </div> <div class="action-panel-control-wrap saved-search-weekly-additional"> <label for="saved-search-weekly-on-day" class="action-panel-label"> Which day? </label> <select id="saved-search-weekly-on-day" class="no-border-panel-selector saved-search-weekly-on-day"> <option value="Sunday">Sunday</option> <option value="Monday">Monday</option> <option value="Tuesday">Tuesday</option> <option value="Wednesday">Wednesday</option> <option value="Thursday">Thursday</option> <option value="Friday">Friday</option> <option value="Saturday">Saturday</option> </select> </div> <div class="action-panel-control-wrap"> <label for="saved-search-report" class="action-panel-label"> Report format: </label> <select id="saved-search-report" class="no-border-panel-selector saved-search-report"> <option value="DocSum">Summary</option> <option value="DocSumText">Summary (text)</option> <option value="Abstract">Abstract</option> <option value="AbstractText">Abstract (text)</option> <option value="MEDLINE">PubMed</option> </select> </div> <div class="action-panel-control-wrap"> <label for="saved-search-amount" class="action-panel-label"> Send at most: </label> <select id="saved-search-amount" class="no-border-panel-selector saved-search-amount"> <option value="1">1 item</option> <option value="5" selected>5 items</option> <option value="10">10 items</option> <option value="20">20 items</option> <option value="50">50 items</option> <option value="100">100 items</option> <option value="200">200 items</option> </select> </div> <div> <input type="checkbox" id="saved-search-send-if-no-result" class="saved-search-send-if-no-result" name="saved-search-send-if-no-result"> <label for="saved-search-send-if-no-result" class="action-panel-label smaller-checkbox"> Send even when there aren't any new results </label> </div> <div class="action-panel-control-wrap option-text-in-email-wrap"> <label for="saved-search-email-text" class="action-panel-label"> Optional text in email: </label> <textarea name="saved-search-email-text" id="saved-search-email-text" class="saved-search-email-text"></textarea> </div> </div> <div class="action-panel-actions"> <button class="action-panel-submit" type="submit" data-loading-label="Saving..." data-ga-category="save_share" data-ga-action="alert" data-ga-label="save"> Save </button> <button class="action-panel-cancel" aria-label="Close 'Your saved search' panel" ref="linksrc=close_saved_search_panel" aria-controls="saved-search-action-panel" aria-expanded="false" data-ga-category="save_share" data-ga-action="alert" data-ga-label="cancel"> Cancel </button> </div> </form> </div> </div> <div id="citation-manager-action-panel" class="citation-manager-action-panel action-panel" aria-hidden="true"> <div class="inner-wrap"> <h2 class="action-panel-heading"> Create a file for external citation management software </h2> <form id="citation-manager-action-panel-form" class="action-panel-content action-form" action="/results-export-ids/" data-by-search-action="/results-export-search-data/" data-by-ids-action="/results-export-ids/" method="post" data-by-search-method="post" data-by-ids-method="post"> <input type="hidden" name="csrfmiddlewaretoken" value="Vdaq4aVLxIvFLjtwgj9nOiXCOXVjq2t2XiUDRuuP6zRgFizqsR8Sy88xKr9K6F9b"> <input name="results-format" type="hidden" value="pubmed"/> <div class="action-panel-actions"> <button class="action-panel-submit" type="submit" data-loading-label="Sending..." data-ga-category="save_share" data-ga-action="citation_manager" data-ga-label="save"> Create file </button> <button class="action-panel-cancel" aria-label="Close 'Send citations to citation manager' panel" ref="linksrc=close_citation_manager_panel" aria-controls="citation-manager-action-panel" aria-expanded="false" data-ga-category="save_share" data-ga-action="citation_manager" data-ga-label="cancel"> Cancel </button> </div> </form> </div> </div> <div id="rss-action-panel" class="rss-action-panel action-panel " aria-hidden="true"> <div class="inner-wrap"> <h2 class="action-panel-heading"> Your RSS Feed </h2> <form id="rss-action-panel-form" class="rss-action-panel-form action-panel-content action-form" data-create-rss-feed-url="/create-rss-feed-url/" data-search-form-term-value=""> <input type="hidden" name="csrfmiddlewaretoken" value="Vdaq4aVLxIvFLjtwgj9nOiXCOXVjq2t2XiUDRuuP6zRgFizqsR8Sy88xKr9K6F9b"> <div class="action-panel-control-wrap"> <label for="rss-name" class="action-panel-label required-field-asterisk"> Name of RSS Feed: </label> <input maxlength="200" placeholder="Name" type="text" name="rss-name" id="rss-name" class="rss-name" value='' required pattern="[^"&=<>\/]*" title="The following characters are not allowed in the Name field: "&=<>/"> </div> <div class="rss-limit-wrap"> <div class="action-panel-control-wrap action-panel-extra-margin-top"> <label for="rss-limit" class="action-panel-label"> Number of items displayed: </label> <select id="rss-limit" class="no-border-panel-selector rss-limit"> <option value="5">5</option> <option value="10">10</option> <option value="15" selected="selected">15</option> <option value="20">20</option> <option value="50">50</option> <option value="100">100</option> </select> </div> </div> <div class="action-panel-actions"> <button class="action-panel-submit" type="submit" data-loading-label="Creating..." data-ga-category="save_share" data-ga-action="alert" data-ga-label="save"> Create RSS </button> <button class="action-panel-cancel" aria-label="Close 'Your RSS' panel" ref="linksrc=close_rss_panel" aria-controls="rss-action-panel" aria-expanded="false" data-ga-category="save_share" data-ga-action="alert" data-ga-label="cancel"> Cancel </button> </div> <div class="action-panel-control-wrap rss-link-copy-wrap"> <label for="rss-link" class="usa-sr-only">RSS Link</label> <input placeholder="Your RSS Feed Link" type="text" name="rss-link" id="rss-link" class="rss-link" title="RSS Link"> <button type="button" disabled class="rss-link-copy-button disabled" data-ga-category="save_share" data-ga-action="rss" data-ga-label="copy"> Copy </button> </div> </form> </div> </div> </div> </div> <div class="article-page" id="article-page" data-article-pmid="9353195"> <aside class="page-sidebar"> <div class="inner-wrap"> <div class="full-text-links"> <div class="full-view"> <h3 class="title"> Full text links </h3> <div class="full-text-links-list"> <a class="link-item dialog-focus" href="https:///www.science.org/doi/10.1126/science.278.5340.1128?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub 0pubmed" target="_blank" rel="noopener" ref="linksrc=fulltextorjournal_fulltext&is_pmc=False&PrId=4487&itool=Abstract-def&log$=linkouticon&uid=9353195&db=pubmed&nlmid=0404511" title="See full text options at Atypon" data-ga-category="full_text" data-ga-action="Atypon" data-ga-label="9353195" ><img src="https://cdn.ncbi.nlm.nih.gov/corehtml/query/egifs/https:--www.science.org-pb-assets-images-logos-pubmed-science.gif" alt="Atypon full text link"><span class="text"> Atypon </span></a> </div> </div> <div class="short-view"> <a href="#" class="full-text-links-button full-text-links-dialog-trigger"> Full text links </a> </div> </div> <div class="actions-buttons sidebar"><h3 class="title">Actions</h3><div class="inner-wrap"><button class="citation-button citation-dialog-trigger" aria-label="Open dialog with citation text in different styles" data-ga-category="save_share" data-ga-action="cite" data-ga-label="open" data-all-citations-url="/9353195/citations/" data-citation-style="nlm" data-pubmed-format-link="/9353195/export/"><span class="button-label">Cite</span></button><link type="text/css" href="ncbi-overlay-block/src/overlay-block.css"><div class="collections-button-container" data-article-id="9353195" data-article-db="pubmed"><button class="collections-button collections-dialog-trigger" aria-label="Save article in MyNCBI collections." data-ga-category="collections_button" data-ga-action="click" data-ga-label="collections_button" data-collections-open-dialog-enabled="false" data-collections-open-dialog-url="https://account.ncbi.nlm.nih.gov/?back_url=https%3A%2F%2Fpubmed.ncbi.nlm.nih.gov%2F9353195%2F%23open-collections-dialog" data-in-collections="false"><span class="button-label">Collections</span></button><div class="overlay" role="dialog"><div id="collections-action-dialog" class="dialog collections-dialog" 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for="collections-action-dialog-new">Create a new collection</label></li><li><input type="radio" id="collections-action-dialog-existing" class="collections-existing" name="collections" value="existing" checked="true" data-ga-category="collections_button" data-ga-action="click" data-ga-label="collections_radio_existing"><label for="collections-action-dialog-existing">Add to an existing collection</label></li></ul></div><div class="controls-wrapper"><div class="action-panel-control-wrap new-collections-controls"><label for="collections-action-dialog-add-to-new" class="action-panel-label required-field-asterisk"> Name your collection: </label><input type="text" name="add-to-new-collection" id="collections-action-dialog-add-to-new" class="collections-action-add-to-new" pattern="[^"&=<>\/]*" title="The following characters are not allowed in the Name field: "&=<>/" maxlength="100" data-ga-category="collections_button" data-ga-action="create_collection" data-ga-label="non_favorties_collection"><div class="collections-new-name-too-long usa-input-error-message selection-validation-message"> Name must be less than 100 characters </div></div><div class="action-panel-control-wrap existing-collections-controls"><label for="collections-action-dialog-add-to-existing" class="action-panel-label"> Choose a collection: </label><select id="collections-action-dialog-add-to-existing" class="action-panel-selector collections-action-add-to-existing" data-ga-category="collections_button" data-ga-action="select_collection" data-ga-label="($('.collections-action-add-to-existing').val() === 'Favorites') ? 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<main class="article-details" id="article-details">   <header class="heading" id="heading"> <div class="full-view" id="full-view-heading"> <div class="article-citation"> <div class="article-source"> <div class="journal-actions dropdown-block"><button id="full-view-journal-trigger" class="journal-actions-trigger trigger" ref="linksrc=journal_actions_btn" title="Science (New York, N.Y.)" tabindex="0" aria-controls="full-view-journal" aria-expanded="false" aria-label="Toggle dropdown menu for journal Science (New York, N.Y.)" data-pinger-ignore> Science </button><div id="full-view-journal" class="journal-actions-dropdown dropdown dropdown-container" hidden aria-label="Dropdown menu for journal Science (New York, N.Y.)"><div class="title">Actions</div><div class="content"><ul class="journal-actions-links"><li><a class="search-in-pubmed-link dropdown-block-link" href="/?term=%22Science%22%5Bjour%5D&sort=date&sort_order=desc" 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</span> </div> <h1 class="heading-title"> A low-barrier hydrogen bond in the catalytic triad of serine proteases? Theory versus experiment </h1> <div class="inline-authors"> <div class="authors"> <div class="authors-list"> <span class="authors-list-item "><a class="full-name" href="/?term=Ash+EL&cauthor_id=9353195" ref="linksrc=author_name_link" data-ga-category="search" data-ga-action="author_link" data-ga-label="E L Ash">E L Ash</a><sup class="affiliation-links"><span class="author-sup-separator"> </span><a class="affiliation-link" title="Department of Biochemistry, Tufts University School of Medicine, Boston, MA 02111, USA." href="#full-view-affiliation-1" ref="linksrc=author_aff"> 1 </a></sup><span class="comma">, </span></span><span class="authors-list-item "><a class="full-name" href="/?term=Sudmeier+JL&cauthor_id=9353195" ref="linksrc=author_name_link" data-ga-category="search" data-ga-action="author_link" data-ga-label="J L Sudmeier">J L Sudmeier</a><span class="comma">, </span></span><span class="authors-list-item "><a class="full-name" href="/?term=De+Fabo+EC&cauthor_id=9353195" ref="linksrc=author_name_link" data-ga-category="search" data-ga-action="author_link" data-ga-label="E C De Fabo">E C De Fabo</a><span class="comma">, </span></span><span class="authors-list-item "><a class="full-name" href="/?term=Bachovchin+WW&cauthor_id=9353195" ref="linksrc=author_name_link" data-ga-category="search" data-ga-action="author_link" data-ga-label="W W Bachovchin">W W Bachovchin</a></span> </div> </div> </div> <div class="short-article-details"> Affiliations <button class="more-details" id="toggle-authors" data-alt-text="Collapse" aria-controls="expanded-authors" aria-expanded="false" data-pinger-ignore data-fetch-url="/9353195/long-authors/" data-id-prefix=""> <span class="title"> Expand </span> </button> </div> <div class="extended-article-details" id="expanded-authors" aria-hidden="true"> <div class="expanded-authors" id="full-view-expanded-authors"> <div class="affiliations"> <h3 class="title"> Affiliation </h3> <ul class="item-list"> <li data-affiliation-id="full-view-affiliation-1" id="full-view-affiliation-1" ><sup class="key">1</sup> Department of Biochemistry, Tufts University School of Medicine, Boston, MA 02111, USA.</li> </ul> </div> </div> </div> <ul class="identifiers" id="full-view-identifiers"> <li> <span class="identifier pubmed"> <span class="id-label"> PMID: </span> <strong class="current-id" title="PubMed ID">9353195</strong> </span> </li> <li> <span class="identifier doi"> <span class="id-label"> DOI: </span> <a class="id-link" target="_blank" rel="noopener" ref="linksrc=article_id_link&article_id=10.1126/science.278.5340.1128&id_type=DOI" href="https://doi.org/10.1126/science.278.5340.1128" data-ga-category="full_text" data-ga-action="DOI" > 10.1126/science.278.5340.1128 </a> </span> </li> </ul> <div class="in-clipboard-label " hidden> Item in Clipboard </div> </div> <div class="short-view" id="short-view-heading"> <h1 class="heading-title"> A low-barrier hydrogen bond in the catalytic triad of serine proteases? Theory versus experiment </h1> <div class="short-citation"> <span class="authors-list"> <span class="authors-list-item "><span class="full-name">E L Ash</span><span class="citation-separator"> et al.</span></span> </span> <span class="citation-journal"> Science<span class="citation-separator">.</span> </span> <span class="date"> <time class="citation-year" datetime="1997">1997</time><span class="citation-separator">.</span> </span> </div> <div class="more-article-details-section with-display-settings"> <button class="more-article-details" id="toggle-article-details" data-alt-text="Hide details" ref="linksrc=toggle_article_details" aria-controls="full-article-details" aria-expanded="false" data-fetch-url="/9353195/long-authors/" data-id-prefix=""> <span class="title">Show details</span> </button> <div class="display-options" data-format-key="format" data-default-format-value="abstract" data-current-format-value="abstract" role="region"> <button class="trigger usa-button" title="Change 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Biochemistry, Tufts University School of Medicine, Boston, MA 02111, USA." href="#short-view-affiliation-1" ref="linksrc=author_aff"> 1 </a></sup><span class="comma">, </span></span><span class="authors-list-item "><a class="full-name" href="/?term=Sudmeier+JL&cauthor_id=9353195" ref="linksrc=author_name_link" data-ga-category="search" data-ga-action="author_link" data-ga-label="J L Sudmeier">J L Sudmeier</a><span class="comma">, </span></span><span class="authors-list-item "><a class="full-name" href="/?term=De+Fabo+EC&cauthor_id=9353195" ref="linksrc=author_name_link" data-ga-category="search" data-ga-action="author_link" data-ga-label="E C De Fabo">E C De Fabo</a><span class="comma">, </span></span><span class="authors-list-item "><a class="full-name" href="/?term=Bachovchin+WW&cauthor_id=9353195" ref="linksrc=author_name_link" data-ga-category="search" data-ga-action="author_link" data-ga-label="W W Bachovchin">W W Bachovchin</a></span> </div> </div> <div class="affiliations"> <h3 class="title"> Affiliation </h3> <ul class="item-list"> <li data-affiliation-id="short-view-affiliation-1" id="short-view-affiliation-1" ><sup class="key">1</sup> Department of Biochemistry, Tufts University School of Medicine, Boston, MA 02111, USA.</li> </ul> </div> </div> <ul class="identifiers" id="short-view-identifiers"> <li> <span class="identifier pubmed"> <span class="id-label"> PMID: </span> <strong class="current-id" title="PubMed ID">9353195</strong> </span> </li> <li> <span class="identifier doi"> <span class="id-label"> DOI: </span> <a class="id-link" target="_blank" rel="noopener" ref="linksrc=article_id_link&article_id=10.1126/science.278.5340.1128&id_type=DOI" href="https://doi.org/10.1126/science.278.5340.1128" data-ga-category="full_text" data-ga-action="DOI" > 10.1126/science.278.5340.1128 </a> </span> </li> </ul> <div class="in-clipboard-label " hidden> Item in Clipboard </div> </div> </div> </header> <div class="actions-buttons inline"><div class="inner-wrap"><button class="full-text-links-button full-text-links-dialog-trigger" title="Open dialog with full text links" ref="linksrc=full_text_links"> Full text links </button><button class="citation-button citation-dialog-trigger" aria-label="Open dialog with citation text in different styles" data-ga-category="save_share" data-ga-action="cite" data-ga-label="open" data-all-citations-url="/9353195/citations/" data-citation-style="nlm" data-pubmed-format-link="/9353195/export/"><span class="button-label">Cite</span></button><button class="more-actions-button more-actions-dialog-trigger" title="Open dialog with more actions to take" ref="linksrc=more_actions_btn"></button><div class="display-options" data-format-key="format" data-default-format-value="abstract" data-current-format-value="abstract" role="region"><button class="trigger usa-button" title="Change format" data-ga-category="display_options" data-ga-action="display_options_dialog"><span class="button-label">Display options</span></button><div class="dropdown" hidden><div class="title"> Display options </div><div class="content"><div class="format-container"><span class="option-label"> Format </span><select name="format" data-initial-value="abstract" aria-label="Display format" id="inline-actions-display-format"><option value="abstract">Abstract</option><option value="pubmed">PubMed</option><option value="pmid">PMID</option></select></div></div></div></div></div></div> <div class="abstract" id="abstract"> <h2 class="title"> Abstract </h2> <div class="abstract-content selected" id="eng-abstract"> <p> Cleland and Kreevoy recently advanced the idea that a special type of hydrogen bond (H-bond), termed a low-barrier hydrogen bond (LBHB), may account for the "missing" transition state stabilization underlying the catalytic power of many enzymes, and Frey et al. have proposed that the H-bond between aspartic acid 102 and histidine 57 in the catalytic triad of serine proteases is an example of a catalytically important LBHB. Experimental facts are here considered regarding the aspartic acid-histidine and cis-urocanic H-bonds that are inconsistent with fundamental tenets of the LBHB hypothesis. The inconsistencies between theory and experiment in these paradigm systems cast doubt on the existence of LBHBs, as currently defined, within enzyme active sites. </p> </div> </div> <p class="disclaimer" id="disclaimer"> <a href="/disclaimer/" target="_blank" data-ga-category="literature_resources" data-ga-action="disclaimer_link" data-ga-label="under_abstract">PubMed Disclaimer</a> </p> <div class="similar-articles" id="similar"> <h2 class="title"> Similar articles </h2> <ul class="articles-list" id="similar-articles-list"> <li class="full-docsum"> <div class="docsum-content" style="display:inline;"> <a class="docsum-title" href="/7661899/" ref="article_id=7661899&linksrc=similar_articles_link&ordinalpos=1" data-ga-category="similar_article" data-ga-action="7661899" data-ga-label=""> A low-barrier hydrogen bond in the catalytic triad of serine proteases. </a> <div class="docsum-citation full-citation"> <span class="docsum-authors full-authors">Frey PA, Whitt SA, Tobin JB.</span> <span class="docsum-authors short-authors">Frey PA, et al.</span> <span class="docsum-journal-citation full-journal-citation">Science. 1994 Jun 24;264(5167):1927-30. doi: 10.1126/science.7661899.</span> <span class="docsum-journal-citation short-journal-citation">Science. 1994.</span> <span class="citation-part">PMID: <span class="docsum-pmid">7661899</span></span> </div> </div> </li> <li class="full-docsum"> <div class="docsum-content" style="display:inline;"> <a class="docsum-title" href="/7766600/" ref="article_id=7766600&linksrc=similar_articles_link&ordinalpos=2" data-ga-category="similar_article" data-ga-action="7766600" data-ga-label=""> Low-barrier hydrogen bonding in molecular complexes analogous to histidine and aspartate in the catalytic triad of serine proteases. </a> <div class="docsum-citation full-citation"> <span class="docsum-authors full-authors">Tobin JB, Whitt SA, Cassidy CS, Frey PA.</span> <span class="docsum-authors short-authors">Tobin JB, et al.</span> <span class="docsum-journal-citation full-journal-citation">Biochemistry. 1995 May 30;34(21):6919-24. doi: 10.1021/bi00021a002.</span> <span class="docsum-journal-citation short-journal-citation">Biochemistry. 1995.</span> <span class="citation-part">PMID: <span class="docsum-pmid">7766600</span></span> </div> </div> </li> <li class="full-docsum"> <div class="docsum-content" style="display:inline;"> <a class="docsum-title" href="/15103633/" ref="article_id=15103633&linksrc=similar_articles_link&ordinalpos=3" data-ga-category="similar_article" data-ga-action="15103633" data-ga-label=""> The low barrier hydrogen bond (LBHB) proposal revisited: the case of the Asp... 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acetylcholinesterase determined by Born-Oppenheimer ab initio QM/MM molecular dynamics simulations. </a> <div class="docsum-citation full-citation"> <span class="docsum-authors full-authors">Zhou Y, Wang S, Zhang Y.</span> <span class="docsum-authors short-authors">Zhou Y, et al.</span> <span class="docsum-journal-citation full-journal-citation">J Phys Chem B. 2010 Jul 8;114(26):8817-25. doi: 10.1021/jp104258d.</span> <span class="docsum-journal-citation short-journal-citation">J Phys Chem B. 2010.</span> <span class="citation-part">PMID: <span class="docsum-pmid">20550161</span></span> <span class="free-resources spaced-citation-item citation-part">Free PMC article.</span> </div> </div> </li> </ul> <div class="actions-bar"> <a class="show-all-linked-articles" data-href="/?linkname=pubmed_pubmed_citedin&from_uid=9353195" data-ga-category="cited_by" data-ga-action="show_all" > See all "Cited by" articles </a> </div> </div> <div id="publication-types" class="publication-types 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href="/?term=%22Serine+Proteinase+Inhibitors%2Fmetabolism%22%5BMeSH%5D&sort=date&sort_order=desc" data-href="/?term=%22Serine+Proteinase+Inhibitors%2Fmetabolism%22%5BMeSH%5D&sort=date&sort_order=desc" ref="linksrc=search_in_pubmed_keyword_link&mesh="Serine Proteinase Inhibitors/metabolism"[MeSH]" data-ga-category="search" data-ga-action="mesh_term" data-ga-label="Serine Proteinase Inhibitors / metabolism"> Search in PubMed </a></li><li><a class="search-in-mesh-link dropdown-block-link" ref="linksrc=search_in_mesh_link" href="https://www.ncbi.nlm.nih.gov/mesh?term=Serine+Proteinase+Inhibitors" data-ga-category="search_mesh" data-ga-action="mesh_term_link" data-ga-label="Serine Proteinase Inhibitors / metabolism"> Search in MeSH </a></li><li><a class="add-to-search-link dropdown-block-link" ref="linksrc=add_to_search_link" role="button" data-search-term=""Serine Proteinase Inhibitors/metabolism"[MeSH]" data-ga-category="search" data-ga-action="add_to_search" data-ga-label=""Serine 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class="keyword-actions-trigger trigger keyword-link" aria-label="Toggle dropdown menu for keyword Boronic Acids" tabindex="0" aria-controls="keyword-actions-substances-0" aria-expanded="false" data-pinger-ignore> Boronic Acids </button><div id="keyword-actions-substances-0" class="keyword-actions-dropdown dropdown dropdown-container" hidden aria-label="Dropdown menu for keyword Boronic Acids"><div class="title">Actions</div><div class="content"><ul class="keyword-actions-links"><li><a class="search-in-pubmed-link dropdown-block-link" href="/?term=%22Boronic+Acids%22%5Bnm%5D&sort=date&sort_order=desc" data-href="/?term=%22Boronic+Acids%22%5Bnm%5D&sort=date&sort_order=desc" ref="linksrc=search_in_pubmed_keyword_link&keyword="Boronic Acids"[nm]" data-ga-category="search" data-ga-action="substance" data-ga-label="Boronic Acids"> Search in PubMed </a></li><li><a class="search-in-mesh-link dropdown-block-link" ref="linksrc=search_in_mesh_link" href="https://www.ncbi.nlm.nih.gov/mesh?term=%22Boronic+Acids%22" data-ga-category="search_mesh" data-ga-action="substance_link" data-ga-label="Boronic Acids"> Search in MeSH </a></li><li><a class="add-to-search-link dropdown-block-link" ref="linksrc=add_to_search_link" role="button" data-search-term=""Boronic Acids"[nm]" data-ga-category="search" data-ga-action="add_to_search" data-ga-label=""Boronic Acids"[nm]" href="#"> Add to Search </a></li></ul></div></div></div></li><li><div class="keyword-actions dropdown-block"><button class="keyword-actions-trigger trigger keyword-link" aria-label="Toggle dropdown menu for keyword Oligopeptides" tabindex="0" aria-controls="keyword-actions-substances-1" aria-expanded="false" data-pinger-ignore> Oligopeptides </button><div id="keyword-actions-substances-1" class="keyword-actions-dropdown dropdown dropdown-container" hidden aria-label="Dropdown menu for keyword Oligopeptides"><div class="title">Actions</div><div class="content"><ul class="keyword-actions-links"><li><a class="search-in-pubmed-link dropdown-block-link" href="/?term=%22Oligopeptides%22%5Bnm%5D&sort=date&sort_order=desc" data-href="/?term=%22Oligopeptides%22%5Bnm%5D&sort=date&sort_order=desc" ref="linksrc=search_in_pubmed_keyword_link&keyword="Oligopeptides"[nm]" data-ga-category="search" data-ga-action="substance" data-ga-label="Oligopeptides"> Search in PubMed </a></li><li><a class="search-in-mesh-link dropdown-block-link" ref="linksrc=search_in_mesh_link" href="https://www.ncbi.nlm.nih.gov/mesh?term=%22Oligopeptides%22" data-ga-category="search_mesh" data-ga-action="substance_link" data-ga-label="Oligopeptides"> Search in MeSH </a></li><li><a class="add-to-search-link dropdown-block-link" ref="linksrc=add_to_search_link" role="button" data-search-term=""Oligopeptides"[nm]" data-ga-category="search" data-ga-action="add_to_search" data-ga-label=""Oligopeptides"[nm]" href="#"> Add to Search </a></li></ul></div></div></div></li><li><div class="keyword-actions dropdown-block"><button class="keyword-actions-trigger trigger keyword-link" aria-label="Toggle dropdown menu for keyword Protons" tabindex="0" aria-controls="keyword-actions-substances-2" aria-expanded="false" data-pinger-ignore> Protons </button><div id="keyword-actions-substances-2" class="keyword-actions-dropdown dropdown dropdown-container" hidden aria-label="Dropdown menu for keyword Protons"><div class="title">Actions</div><div class="content"><ul class="keyword-actions-links"><li><a class="search-in-pubmed-link dropdown-block-link" href="/?term=%22Protons%22%5Bnm%5D&sort=date&sort_order=desc" data-href="/?term=%22Protons%22%5Bnm%5D&sort=date&sort_order=desc" ref="linksrc=search_in_pubmed_keyword_link&keyword="Protons"[nm]" data-ga-category="search" data-ga-action="substance" data-ga-label="Protons"> Search in PubMed </a></li><li><a class="search-in-mesh-link dropdown-block-link" ref="linksrc=search_in_mesh_link" href="https://www.ncbi.nlm.nih.gov/mesh?term=%22Protons%22" data-ga-category="search_mesh" data-ga-action="substance_link" data-ga-label="Protons"> Search in MeSH </a></li><li><a class="add-to-search-link dropdown-block-link" ref="linksrc=add_to_search_link" role="button" data-search-term=""Protons"[nm]" data-ga-category="search" data-ga-action="add_to_search" data-ga-label=""Protons"[nm]" href="#"> Add to Search </a></li></ul></div></div></div></li><li><div class="keyword-actions dropdown-block"><button class="keyword-actions-trigger trigger keyword-link" aria-label="Toggle dropdown menu for keyword Serine Proteinase Inhibitors" tabindex="0" aria-controls="keyword-actions-substances-3" aria-expanded="false" data-pinger-ignore> Serine Proteinase Inhibitors </button><div id="keyword-actions-substances-3" class="keyword-actions-dropdown dropdown dropdown-container" hidden aria-label="Dropdown menu for keyword Serine Proteinase Inhibitors"><div class="title">Actions</div><div class="content"><ul class="keyword-actions-links"><li><a class="search-in-pubmed-link dropdown-block-link" href="/?term=%22Serine+Proteinase+Inhibitors%22%5Bnm%5D&sort=date&sort_order=desc" data-href="/?term=%22Serine+Proteinase+Inhibitors%22%5Bnm%5D&sort=date&sort_order=desc" ref="linksrc=search_in_pubmed_keyword_link&keyword="Serine Proteinase Inhibitors"[nm]" data-ga-category="search" data-ga-action="substance" data-ga-label="Serine Proteinase Inhibitors"> Search in PubMed </a></li><li><a class="search-in-mesh-link dropdown-block-link" ref="linksrc=search_in_mesh_link" href="https://www.ncbi.nlm.nih.gov/mesh?term=%22Serine+Proteinase+Inhibitors%22" data-ga-category="search_mesh" data-ga-action="substance_link" data-ga-label="Serine Proteinase Inhibitors"> Search in MeSH </a></li><li><a class="add-to-search-link dropdown-block-link" ref="linksrc=add_to_search_link" role="button" data-search-term=""Serine Proteinase Inhibitors"[nm]" data-ga-category="search" 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data-href="/?term=%22O-methyl-succinyl-alanyl-alanyl-prolyl-borovaline%22%5Bnm%5D&sort=date&sort_order=desc" ref="linksrc=search_in_pubmed_keyword_link&keyword="O-methyl-succinyl-alanyl-alanyl-prolyl-borovaline"[nm]" data-ga-category="search" data-ga-action="substance" data-ga-label="O-methyl-succinyl-alanyl-alanyl-prolyl-borovaline"> Search in PubMed </a></li><li><a class="search-in-mesh-link dropdown-block-link" ref="linksrc=search_in_mesh_link" href="https://www.ncbi.nlm.nih.gov/mesh?term=%22O-methyl-succinyl-alanyl-alanyl-prolyl-borovaline%22" data-ga-category="search_mesh" data-ga-action="substance_link" data-ga-label="O-methyl-succinyl-alanyl-alanyl-prolyl-borovaline"> Search in MeSH </a></li><li><a class="add-to-search-link dropdown-block-link" ref="linksrc=add_to_search_link" role="button" data-search-term=""O-methyl-succinyl-alanyl-alanyl-prolyl-borovaline"[nm]" data-ga-category="search" data-ga-action="add_to_search" 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</button><div id="keyword-actions-substances-8" class="keyword-actions-dropdown dropdown dropdown-container" hidden aria-label="Dropdown menu for keyword Subtilisins"><div class="title">Actions</div><div class="content"><ul class="keyword-actions-links"><li><a class="search-in-pubmed-link dropdown-block-link" href="/?term=%22Subtilisins%22%5Bnm%5D&sort=date&sort_order=desc" data-href="/?term=%22Subtilisins%22%5Bnm%5D&sort=date&sort_order=desc" ref="linksrc=search_in_pubmed_keyword_link&keyword="Subtilisins"[nm]" data-ga-category="search" data-ga-action="substance" data-ga-label="Subtilisins"> Search in PubMed </a></li><li><a class="search-in-mesh-link dropdown-block-link" ref="linksrc=search_in_mesh_link" href="https://www.ncbi.nlm.nih.gov/mesh?term=%22Subtilisins%22" data-ga-category="search_mesh" data-ga-action="substance_link" data-ga-label="Subtilisins"> Search in MeSH </a></li><li><a class="add-to-search-link dropdown-block-link" ref="linksrc=add_to_search_link" role="button" data-search-term=""Subtilisins"[nm]" data-ga-category="search" data-ga-action="add_to_search" data-ga-label=""Subtilisins"[nm]" href="#"> Add to Search </a></li></ul></div></div></div></li><li><div class="keyword-actions dropdown-block"><button class="keyword-actions-trigger trigger keyword-link" aria-label="Toggle dropdown menu for keyword myxobacter alpha-lytic proteinase" tabindex="0" aria-controls="keyword-actions-substances-9" aria-expanded="false" data-pinger-ignore> myxobacter alpha-lytic proteinase </button><div id="keyword-actions-substances-9" class="keyword-actions-dropdown dropdown dropdown-container" hidden aria-label="Dropdown menu for keyword myxobacter alpha-lytic proteinase"><div class="title">Actions</div><div class="content"><ul class="keyword-actions-links"><li><a class="search-in-pubmed-link dropdown-block-link" href="/?term=%22myxobacter+alpha-lytic+proteinase%22%5Bnm%5D&sort=date&sort_order=desc" 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A low-barrier hydrogen bond in the catalytic triad of serine proteases? Theory versus experiment - PubMed