title: Substrate positioning in chitinase A, a processive chito-biohydrolase from Serratia marcescens.
abstract: The contributions of the -3 subsite and a putative +3 subsite to substrate positioning in ChiA from Serratia marcescens have been investigated by comparing how ChiA and its -3 subsite mutant W167A interact with soluble substrates. The data show that Trp - GlcNAc stacking in the -3 subsite rigidifies the protein backbone supporting the formation of the intermolecular interaction network that is necessary for the recognition and positioning of the N-acetyl groups before the -1 subsite. The +3 subsite exhibits considerable substrate affinity that may promote endo-activity in ChiA and/or assist in expelling dimeric products from the +1 and +2 subsites during processive hydrolysis.
authors.affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway.
authors.forename: Anne Line
authors.initials: AL
authors.lastname: Norberg
authors.forename: Anette I
authors.initials: AI
authors.lastname: Dybvik
authors.forename: Henrik
authors.initials: H
authors.lastname: Zakariassen
authors.forename: Michael
authors.initials: M
authors.lastname: Mormann
authors.forename: Jasna
authors.initials: J
authors.lastname: Peter-Katalinić
authors.forename: Vincent G H
authors.initials: VG
authors.lastname: Eijsink
authors.forename: Morten
authors.initials: M
authors.lastname: Sørlie
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D020134:Catalytic Domain; D002417:Cattle; D002686:Chitin / Q000737:chemistry / Q000378:metabolism*; D002688:Chitinases / Q000737:chemistry* / Q000378:metabolism*; D007527:Isoenzymes / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D017434:Protein Structure, Tertiary; D012706:Serratia marcescens / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D007527:Isoenzymes; D002686:Chitin; D002688:Chitinases