Design of a pH‐dependent cellulose‐binding domain

FEBS Letters

Teeri, Tuula T.¹  Nevanen, Tarja²  Linder, Markus² 

[1] Royal Institute of Technology, Department of Biotechnology, SE-10044 Stockholm, Sweden;VTT Biotechnology and Food Research, P.O. Box 1500, FIN-02044 VTT, Finland

关键词: Cellulose-binding domain;    Histidine titration;    Protein-carbohydrate interaction;    Protein engineering;    Cellulase;    Trichoderma reesei;    CBD;    cellulose-binding domain;   

DOI  :  10.1016/S0014-5793(99)00253-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Protein-carbohydrate interactions typically rely on aromatic stacking interactions of tyrosine, phenylalanine and tryptophan side chains with the sugar rings whereas histidine residues are rarely involved. The small cellulose-binding domain of the Cel7A cellobiohydrolase (formerly CBHI) from Trichoderma reesei binds to crystalline cellulose primarily using a planar strip of three tyrosine side chains. Binding of the wild-type Cel7A CBD is practically insensitive to pH. Here we have investigated how histidine residues mediate the binding interaction and whether the protonation of a histidine side chain makes the binding sensitive to pH. Protein engineering of the Cel7A CBD was thus used to replace the tyrosine residues in two different positions with histidine residues. All of the mutants exhibited a clear pH-dependency of the binding, in clear contrast to the wild-type. Although the binding of the mutants at optimal pH was less than for the wild-type, in one case, Y31H, this binding almost reached the wild-type level.

【 授权许可】

Unknown