BACKGROUND: Chitinases cleave the beta-1-4-glycosidic bond between the N-acetyl-D-glucosamine units of which chitin is comprised. Chitinases are present in plants, bacteria and fungi, but whereas structures are available for two prototypic plant enzymes, no structure is available for a bacterial or fungal chitinase. RESULTS: To redress this imbalance, the structure of native chitinase A from Serratia marcescens has been solved by multiple isomorphous replacement and refined at 2.3 A resolution, resulting in a crystallographic R-factor of 16.2%. The enzyme comprises three domains: an all beta-strand amino-terminal domain, a catalytic alpha/beta-barrel domain, and a small alpha+beta-fold domain. There are several residues with unusual geometries in the structure. Structure determination of chitinase A in complex with N,N',N",N"'-tetra-acetylo-chitotetraose, together with biochemical and sequence analysis data, enabled the positions of the active-site and catalytic residues to be proposed. CONCLUSIONS: The reaction mechanism seems to be similar to that of lysozyme and most other glycosylhydrolases, i.e. general acid-base catalysis. The role of the amino-terminal domain could not be identified, but it has similarities to the fibronectin III domain. This domain may possibly facilitate the interaction of chitinase A with chitin.
BACKGROUND: Chitinases cleave the beta-1-4-glycosidic bond between the N-acetyl-D-glucosamine units of which chitin is comprised. Chitinases are present in plants, bacteria and fungi, but whereas structures are available for two prototypic plant enzymes, no structure is available for a bacterial or fungal chitinase. RESULTS: To redress this imbalance, the structure of native chitinase A from Serratia marcescens has been solved by multiple isomorphous replacement and refined at 2.3 A resolution, resulting in a crystallographic R-factor of 16.2%. The enzyme comprises three domains: an all beta-strand amino-terminal domain, a catalytic alpha/beta-barrel domain, and a small alpha+beta-fold domain. There are several residues with unusual geometries in the structure. Structure determination of chitinase A in complex with N,N',N",N"'-tetra-acetylo-chitotetraose, together with biochemical and sequence analysis data, enabled the positions of the active-site and catalytic residues to be proposed. CONCLUSIONS: The reaction mechanism seems to be similar to that of lysozyme and most other glycosylhydrolases, i.e. general acid-base catalysis. The role of the amino-terminal domain could not be identified, but it has similarities to the fibronectin III domain. This domain may possibly facilitate the interaction of chitinase A with chitin.
Authors: D M van Aalten; B Synstad; M B Brurberg; E Hough; B W Riise; V G Eijsink; R K Wierenga Journal: Proc Natl Acad Sci U S A Date: 2000-05-23 Impact factor: 11.205
Authors: D M van Aalten; D Komander; B Synstad; S Gåseidnes; M G Peter; V G Eijsink Journal: Proc Natl Acad Sci U S A Date: 2001-07-31 Impact factor: 11.205
Authors: Aizi Nor Mazila Ramli; Nor Muhammad Mahadi; Mohd Shahir Shamsir; Amir Rabu; Kwee Hong Joyce-Tan; Abdul Munir Abdul Murad; Rosli Md Illias Journal: J Comput Aided Mol Des Date: 2012-06-19 Impact factor: 3.686
Authors: Manju B Joshi; Matthew E Rogers; Alison M Shakarian; Mat Yamage; Saeed A Al-Harthi; Paul A Bates; Dennis M Dwyer Journal: J Biol Chem Date: 2004-11-22 Impact factor: 5.157