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540 a.a.
Key reference
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.
Literature references that cite this PDB file's key reference
PubMed id Reference
19244232 H.Zakariassen, B.B.Aam, S.J.Horn, K.M.Vårum, M.Sørlie, and V.G.Eijsink (2009).
Aromatic Residues in the Catalytic Center of Chitinase A from Serratia marcescens Affect Processivity, Enzyme Activity, and Biomass Converting Efficiency.J Biol Chem, 284, 10610-10617.
19696236 T.Taira, H.Hayashi, Y.Tajiri, S.Onaga, G.Uechi, H.Iwasaki, T.Ohnuma, and T.Fukamizo (2009).
A plant class V chitinase from a cycad (Cycas revoluta): biochemical characterization, cDNA isolation, and posttranslational modification.Glycobiology, 19, 1452-1461.
16794344 N.N.Aronson, and B.A.Halloran (2006).
Optimum substrate size and specific anomer requirements for the reducing-end glycoside hydrolase di-N-acetylchitobiase.Biosci Biotechnol Biochem, 70, 1537-1541. The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time.
