1RD6

Crystal Structure of S. Marcescens Chitinase A Mutant W167A

Summary for 1RD6

• Entry DOI: 10.2210/pdb1rd6/pdb
• Descriptor: Chitinase A (2 entities in total)
• Functional Keywords: chitinase a, hydrolase
• Biological source: Serratia marcescens
• Total number of polymer chains: 1
• Total formula weight: 60972.43

Authors

Aronson, N.N.,Halloran, B.A.,Alexyev, M.F.,Zhou, X.E.,Wang, Y.,Meehan, E.J.,Chen, L. (deposition date: 2003-11-05, release date: 2004-12-07, Last modification date: 2024-11-20)

Primary citation

Aronson, N.N.,Halloran, B.A.,Alexeyev, M.F.,Zhou, X.E.,Wang, Y.,Meehan, E.J.,Chen, L.
Mutation of a conserved tryptophan in the chitin-binding cleft of Serratia marcescens chitinase A enhances transglycosylation.
Biosci.Biotechnol.Biochem., 70:243-251, 2006

PubMed Abstract: Family 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.

PubMed: 16428843

Experimental method

X-RAY DIFFRACTION (2.6 Å)