Cloning and Characterization of an Exo-Xylogucanase from Rumenal Microbial Metagenome

Title: Cloning and Characterization of an Exo-Xylogucanase from Rumenal Microbial Metagenome

Volume: 17 Issue: 6

Author(s): Dominic D.W.S. Wong, Victor J. Chan, Amanda A. McCormack and Sarah B. Batt

Affiliation:

Keywords: Xyloglucanase, exo-xyloglucanase, xyloglucan-specific exo-glucanase, tamarind xyloglucan, xyloglucan oligosaccharide, metagenome

Abstract: A novel exo-glucanase gene (xeg5B) was isolated from a rumenal microbial metagenome, cloned, and expressed in E. coli. The 1548 bp gene coded for a protein of 516 amino acids, which assumed an (α/β)8 fold typical of glycoside hydrolase (GH) family 5. The protein molecule consisted of a loop segment blocking one end of the active site, which potentially provided the enzyme with exo-acting property. The recombinant enzyme showed exclusive specificity towards xyloglucan and oligoxyloglucan substrates with no detectable activity on unsubstituted linear glucans, CMC, laminarin, and lichenan. The major end products of exhaustive hydrolysis were XX (tetrasaccharide) and XG (trisaccharide). The hydrolysis of tamarind xyloglucan followed the Michaelis-Menten kinetics, yielding Km and Vmax of 2.12±0.13 mg/ml and 0.17±0.01 mg/ml/min (37°C, pH 6.0), respectively.

Cite this article as:

D.W.S. Wong Dominic, J. Chan Victor, A. McCormack Amanda and B. Batt Sarah, Cloning and Characterization of an Exo-Xylogucanase from Rumenal Microbial Metagenome, Protein & Peptide Letters 2010; 17 (6) . https://dx.doi.org/10.2174/092986610791190381