The N-terminal family 22 carbohydrate-binding module of xylanase 10B of Clostridium themocellum is not a thermostabilizing domain

FEMS Microbiol Lett. 2004 Sep 1;238(1):71-8. doi: 10.1016/j.femsle.2004.07.019.

Abstract

Xylanase Xyn10B from Clostridium thermocellum is a modular enzyme that contains two family 22 carbohydrate binding modules N- (CBM22-1) and C- (CBM22-2) terminal of the family 10 glycoside hydrolase catalytic domain (GH10). In a previous study, we showed that removal of CBM22-1 reduces the resistance to thermoinactivation of the enzyme suggesting that this module is a thermostabilizing domain. Here, we show that it is the module border on the N-terminal side of GH10 that confers resistance to thermoinactivation and to proteolysis. Therefore, CBM22-1 does not function as a thermostabilizing domain and the role for this apparently non-functional CBM remains elusive.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Catalytic Domain
  • Clostridium / enzymology*
  • Endo-1,4-beta Xylanases / chemistry*
  • Endo-1,4-beta Xylanases / genetics
  • Endo-1,4-beta Xylanases / isolation & purification
  • Endo-1,4-beta Xylanases / metabolism*
  • Enzyme Stability
  • Hot Temperature
  • Kinetics
  • Mutagenesis, Site-Directed
  • Mutation
  • Peptide Hydrolases / metabolism
  • Polysaccharides / metabolism
  • Protein Structure, Tertiary*
  • Sequence Deletion
  • Solubility
  • Xylans / metabolism

Substances

  • Polysaccharides
  • Xylans
  • Endo-1,4-beta Xylanases
  • Peptide Hydrolases