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Crystal Structure of S. Marcescens Chitinase A Mutant W167ACrystal Structure of S. Marcescens Chitinase A Mutant W167A
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedFamily 18 chitinases have the signature peptide DGXDXDXE forming the fourth beta-strand in the (beta/alpha)8-barrel of their catalytic domain. The carboxyl-end glutamic acid, E315 in Serratia marcescens chitinase A, serves as the acid/base during chitin hydrolysis, and the side-chain of the preceding aspartic acid, D313, helps to position correctly the N-acetyl moiety of the glycosyl sugar undergoing hydrolysis. Chitin substrates are bound within a long cleft across the top of the barrel, whose floor consists of aromatic residues that hydrophobically stack with every other GlcNAc. Alanine substitution of the conserved Trp167 at the -3 subsite in Serratia marcescens chitinase A enhanced transglycosylation. Higher oligosaccharides were formed from both chitin tetra- and pentasaccharide, and the only hydrolytic product from chitin trisaccharide was the disaccharide. Greater retention of the glycosyl fragment at the active site of the -3 mutant of Serratia marcescens chitinase A might favor transglycosylation due to a stabilized conformation of its D313. Mutation of a conserved tryptophan in the chitin-binding cleft of Serratia marcescens chitinase A enhances transglycosylation.,Aronson NN Jr, Halloran BA, Alexeyev MF, Zhou XE, Wang Y, Meehan EJ, Chen L Biosci Biotechnol Biochem. 2006 Jan;70(1):243-51. PMID:16428843[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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