PDBsum entry: 1rd6

Hydrolase

PDB id: 1rd6

Contents

Protein chain

540 a.a. *

Waters ×285

* Residue conservation analysis

PDB id:

1rd6

Name:

Hydrolase

Title:

Crystal structure of s. Marcescens chitinase a mutant w167a

Structure:

Chitinase a. Chain: a. Engineered: yes. Mutation: yes

Source:

Serratia marcescens. Organism_taxid: 615. Gene: chia. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

Resolution:

2.60Å R-factor: 0.195 R-free: 0.235

Authors:

N.N.Aronson,B.A.Halloran,M.F.Alexyev,X.E.Zhou,Y.Wang, E.J.Meehan,L.Chen

Key ref:

N.N.Aronson et al. (2006). Mutation of a conserved tryptophan in the chitin-binding cleft of Serratia marcescens chitinase A enhances transglycosylation. Biosci Biotechnol Biochem, 70, 243-251. PubMed id: 16428843 DOI: 10.1271/bbb.70.243

Date:

05-Nov-03 Release date: 07-Dec-04

Protein chain

P07254  (CHIA_SERMA) -  Chitinase A

Seq: 563 a.a.

Struc: 540 a.a.*

* PDB and UniProt seqs differ at 8 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.2.1.14 - Chitinase.
• Reaction: Hydrolysis of the 1,4-beta-linkages of N-acetyl-D-glucosamine polymers of chitin.

 Gene Ontology (GO) functional annotation 

• Biological process: carbohydrate metabolic process (2 terms)
• Biochemical function: catalytic activity (4 terms)

DOI no: 10.1271/bbb.70.243

Biosci Biotechnol Biochem 70:243-251 (2006)

PubMed id: 16428843

Mutation of a conserved tryptophan in the chitin-binding cleft of Serratia marcescens chitinase A enhances transglycosylation.

N.N.Aronson, B.A.Halloran, M.F.Alexeyev, X.E.Zhou, Y.Wang, E.J.Meehan, L.Chen.

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.