{"id":531,"date":"2026-04-15T13:36:00","date_gmt":"2026-04-15T13:36:00","guid":{"rendered":"https:\/\/citations.tools.bio-logic.fr\/?p=531"},"modified":"2026-04-15T13:36:00","modified_gmt":"2026-04-15T13:36:00","slug":"structure-and-activity-of-chix-a-peptidoglycan-hydrolase-required-for-chitinase-secretion-by-serratia-marcescens","status":"publish","type":"post","link":"https:\/\/citations.tools.bio-logic.fr\/?p=531","title":{"rendered":"Structure and activity of ChiX: a peptidoglycan hydrolase required for chitinase secretion by <i>Serratia marcescens<\/i>"},"content":{"rendered":"<h4>DOI:<\/h4>\n<p><a href=\"https:\/\/doi.org\/10.1042\/bcj20170633\" target=\"_blank\" rel=\"noopener\">10.1042\/bcj20170633<\/a><\/p>\n<h4>Authors:<\/h4>\n<p>Richard A. Owen, Paul K. Fyfe, Adam Lodge, Jacob Biboy, Waldemar Vollmer, William N. Hunter, Frank Sargent<\/p>\n<h4>Abstract:<\/h4>\n<p>The Gram-negative bacterium <i>Serratia marcescens<\/i> secretes many proteins that are involved in extracellular chitin degradation. This so-called chitinolytic machinery includes three types of chitinase enzymes and a lytic polysaccharide monooxygenase. An operon has been identified in <i>S. marcescens<\/i>, <i>chiWXYZ<\/i>, that is thought to be involved in the secretion of the chitinolytic machinery. Genetic evidence points to the ChiX protein being a key player in the secretion mechanism, since deletion of the <i>chiX<\/i> gene in <i>S. marcescens<\/i> led to a mutant strain blocked for secretion of all members of the chitinolytic machinery. In this work, a detailed structural and biochemical characterisation of ChiX is presented. The high-resolution crystal structure of ChiX reveals the protein to be a member of the LAS family of peptidases. ChiX is shown to be a zinc-containing metalloenzyme, and <i>in vitro<\/i> assays demonstrate that ChiX is an l-Ala d-Glu endopeptidase that cleaves the cross-links in bacterial peptidoglycan. This catalytic activity is shown to be intimately linked with the secretion of the chitinolytic machinery, since substitution of the ChiX Asp-120 residue results in a variant protein that is both unable to digest peptidoglycan and cannot rescue the phenoytype of a <i>chiX<\/i> mutant strain.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>DOI: 10.1042\/bcj20170633 Authors: Richard A. Owen, Paul K. Fyfe, Adam Lodge, Jacob Biboy, Waldemar Vollmer, William N. Hunter, Frank Sargent Abstract: The Gram-negative bacterium Serratia marcescens secretes many proteins that are involved in extracellular chitin degradation. This so-called chitinolytic machinery includes three types of chitinase enzymes and a lytic polysaccharide monooxygenase. An operon has been [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-531","post","type-post","status-publish","format-standard","hentry","category-freeze-quench"],"_links":{"self":[{"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=\/wp\/v2\/posts\/531","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=531"}],"version-history":[{"count":0,"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=\/wp\/v2\/posts\/531\/revisions"}],"wp:attachment":[{"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=531"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=531"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=531"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}