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Characterization of two novel bacterial type A exo-chitobiose hydrolases having C-terminal 5/12-type carbohydrate-binding modules.
- Source :
-
Applied Microbiology & Biotechnology . Jun2017, Vol. 101 Issue 11, p4533-4546. 14p. - Publication Year :
- 2017
-
Abstract
- Type A chitinases (EC 3.2.1.14), GH family 18, attack chitin ((1 → 4)-2-acetamido-2-deoxy-β- d-glucan) and chito-oligosaccharides from the reducing end to catalyze release of chitobiose ( N, N′-diacetylchitobiose) via hydrolytic cleavage of N-acetyl-β- d-glucosaminide (1 → 4)-β-linkages and are thus ' exo-chitobiose hydrolases.' In this study, the chitinase type A from Serratia marcescens (SmaChiA) was used as a template for identifying two novel exo-chitobiose hydrolase type A enzymes, FbalChi18A and MvarChi18A, originating from the marine organisms Ferrimonas balearica and Microbulbifer variabilis, respectively. Both FbalChi18A and MvarChi18A were recombinantly expressed in Escherichia coli and were confirmed to exert exo-chitobiose hydrolase activity on chito-oligosaccharides, but differed in temperature and pH activity response profiles. Amino acid sequence comparison of the catalytic β/α barrel domain of each of the new enzymes showed individual differences, but ~69% identity of each to that of SmaChiA and highly conserved active site residues. Superposition of a model substrate on 3D structural models of the catalytic domain of the enzymes corroborated exo-chitobiose hydrolase type A activity for FbalChi18A and MvarChi18A, i.e., substrate attack from the reducing end. A main feature of both of the new enzymes was the presence of C-terminal 5/12 type carbohydrate-binding modules (SmaChiA has no C-terminal carbohydrate binding module). These new enzymes may be useful tools for utilization of chitin as an N-acetylglucosamine donor substrate via chitobiose. [ABSTRACT FROM AUTHOR]
- Subjects :
- *CHITIN
*GLYCOSIDASES
*CATALYTIC activity
*CHITINASE genetics
*MARINE organisms
Subjects
Details
- Language :
- English
- ISSN :
- 01757598
- Volume :
- 101
- Issue :
- 11
- Database :
- Academic Search Index
- Journal :
- Applied Microbiology & Biotechnology
- Publication Type :
- Academic Journal
- Accession number :
- 123190967
- Full Text :
- https://doi.org/10.1007/s00253-017-8198-4