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Article: Crystal structures of a family 19 chitinase from Brassica juncea show flexibility of binding cleft loops

TitleCrystal structures of a family 19 chitinase from Brassica juncea show flexibility of binding cleft loops
Authors
KeywordsBrassica juncea
Chitinase
Conformational changes
Endochitinase
Family 19
Issue Date2007
PublisherWiley-Blackwell Publishing Ltd.. The Journal's web site is located at http://www.febsjournal.org/
Citation
Febs Journal, 2007, v. 274 n. 14, p. 3695-3703 How to Cite?
AbstractBrassica juncea chitinase is an endo-acting, pathogenesis-related protein that is classified into glycoside hydrolase family 19, with highest homology (50-60%) in its catalytic domain to class I plant chitinases. Here we report X-ray structures of the chitinase catalytic domain from wild-type (apo, as well as with chloride ions bound) and a Glu234Ala mutant enzyme, solved by molecular replacement and refined at 1.53, 1.8 and 1.7 Å resolution, respectively. Confirming our earlier mutagenesis studies, the active-site residues are identified as Glu212 and Glu234. Glu212 is believed to be the catalytic acid in the reaction, whereas Glu234 is thought to have a dual role, both activating a water molecule in its attack on the anomeric carbon, and stabilizing the charged intermediate. The molecules in the various structures differ significantly in the conformation of a number of loops that border the active-site cleft. The differences suggest an opening and closing of the enzyme during the catalytic cycle. Chitin is expected to dock first near Glu212, which will protonate it. Conformational changes then bring Glu234 closer, allowing it to assist in the following steps. These observations provide important insights into catalysis in family 19 chitinases. © 2007 The Authors.
Persistent Identifierhttp://hdl.handle.net/10722/89264
ISSN
2015 Impact Factor: 4.237
2015 SCImago Journal Rankings: 2.141
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorUbhayasekera, Wen_HK
dc.contributor.authorTang, CMen_HK
dc.contributor.authorHo, SWTen_HK
dc.contributor.authorBerglund, Gen_HK
dc.contributor.authorBergfors, Ten_HK
dc.contributor.authorChye, MLen_HK
dc.contributor.authorMowbray, SLen_HK
dc.date.accessioned2010-09-06T09:54:38Z-
dc.date.available2010-09-06T09:54:38Z-
dc.date.issued2007en_HK
dc.identifier.citationFebs Journal, 2007, v. 274 n. 14, p. 3695-3703en_HK
dc.identifier.issn1742-464Xen_HK
dc.identifier.urihttp://hdl.handle.net/10722/89264-
dc.description.abstractBrassica juncea chitinase is an endo-acting, pathogenesis-related protein that is classified into glycoside hydrolase family 19, with highest homology (50-60%) in its catalytic domain to class I plant chitinases. Here we report X-ray structures of the chitinase catalytic domain from wild-type (apo, as well as with chloride ions bound) and a Glu234Ala mutant enzyme, solved by molecular replacement and refined at 1.53, 1.8 and 1.7 Å resolution, respectively. Confirming our earlier mutagenesis studies, the active-site residues are identified as Glu212 and Glu234. Glu212 is believed to be the catalytic acid in the reaction, whereas Glu234 is thought to have a dual role, both activating a water molecule in its attack on the anomeric carbon, and stabilizing the charged intermediate. The molecules in the various structures differ significantly in the conformation of a number of loops that border the active-site cleft. The differences suggest an opening and closing of the enzyme during the catalytic cycle. Chitin is expected to dock first near Glu212, which will protonate it. Conformational changes then bring Glu234 closer, allowing it to assist in the following steps. These observations provide important insights into catalysis in family 19 chitinases. © 2007 The Authors.en_HK
dc.languageengen_HK
dc.publisherWiley-Blackwell Publishing Ltd.. The Journal's web site is located at http://www.febsjournal.org/en_HK
dc.relation.ispartofFEBS Journalen_HK
dc.rightsThe F E B S Journal. Copyright © Blackwell Publishing Ltd.en_HK
dc.subjectBrassica junceaen_HK
dc.subjectChitinaseen_HK
dc.subjectConformational changesen_HK
dc.subjectEndochitinaseen_HK
dc.subjectFamily 19en_HK
dc.titleCrystal structures of a family 19 chitinase from Brassica juncea show flexibility of binding cleft loopsen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=1742-464X&volume=274&spage=3695&epage=3703&date=2007&atitle=Crystal+structures+of+a+family+19+chitinase+from+Brassica+juncea+show+flexibility+of+binding+cleft+loopsen_HK
dc.identifier.emailChye, ML: mlchye@hkucc.hku.hken_HK
dc.identifier.authorityChye, ML=rp00687en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1111/j.1742-4658.2007.05906.xen_HK
dc.identifier.pmid17608716-
dc.identifier.scopuseid_2-s2.0-34447306024en_HK
dc.identifier.hkuros130075en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-34447306024&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume274en_HK
dc.identifier.issue14en_HK
dc.identifier.spage3695en_HK
dc.identifier.epage3703en_HK
dc.identifier.isiWOS:000247904900020-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridUbhayasekera, W=6506474701en_HK
dc.identifier.scopusauthoridTang, CM=16640286200en_HK
dc.identifier.scopusauthoridHo, SWT=9744286500en_HK
dc.identifier.scopusauthoridBerglund, G=7102609780en_HK
dc.identifier.scopusauthoridBergfors, T=6603598085en_HK
dc.identifier.scopusauthoridChye, ML=7003905460en_HK
dc.identifier.scopusauthoridMowbray, SL=7004344618en_HK
dc.identifier.citeulike1454571-

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