Cloning and characterization of a beta-1,4-mannanase 5C possessing a family 27 carbohydrate-binding module from a marine bacterium, Vibrio sp. strain MA-138.
The beta-1,4-mannanase 5C gene (man5C) of Vibrio sp. strain MA-138 was cloned and expressed in Escherichia coli. The man5C gene consisted of 2,010 bp nucleotides encoding a protein of 669 amino acids with a predicted molecular weight of 76,309. beta-1,4-Mannanase (Man5C) is a modular enzyme composed of a catalytic module belonging to glycoside hydrolase family 5, a linker region, and a putative carbohydrate-binding module (CBM) belonging to family 27. Recombinant Man5C exhibited maximal activity at 50 degrees C at pH 7.0, and it had a K(m) of 0.6 mg ml(-1) and a V(max) of 556.2 micromol min(-1) mumol(-1) for glucomannan. Binding studies revealed that the C-terminal putative CBM27 had the ability to bind soluble beta-mannans and contributed to increasing the rate of depolymerization by binding to the polymeric substrate. Man5C of Vibrio sp. MA-138 is the first non-extremophile enzyme to be identified as a beta-mannanase possessing CBM27.
Tanaka
Megumi
M
Graduate School of Bioresources, Mie University.
Umemoto
Yoshiaki
Y
Okamura
Hidenori
H
Nakano
Daiichirou
D
Tamaru
Yutaka
Y
Araki
Toshiyoshi
T
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D007700:Kinetics; D008351:Mannans / Q000378:metabolism; D008970:Molecular Weight; D011485:Protein Binding; D014733:Vibrio / Q000201:enzymology*; D044902:beta-Mannosidase / Q000235:genetics / Q000378:metabolism*
D008351:Mannans; D044902:beta-Mannosidase