Tryptophan 272:: an essential determinant of crystalline cellulose degradation by Trichoderma reesei cellobiohydrolase Cel6A

被引：99

作者：

Koivula, A

Kinnari, T

Harjunpää, V

Ruohonen, L

Teleman, A

Drakenberg, T

Rouvinen, J

Jones, TA

Teeri, TT

机构：

[1] VTT Biotechnol & Food Res, FIN-02044 Espoo, Finland

[2] VTT Chem Technol, FIN-02044 Espoo, Finland

[3] BMC, Dept Biol Mol, S-75124 Uppsala, Sweden

来源：

FEBS LETTERS | 1998年 / 429卷 / 03期

关键词：

cellulase; crystalline cellulose; mutagenesis; oligosaccharide; sugar binding site;

D O I：

10.1016/S0014-5793(98)00596-1

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Trichoderma reesei cellobiohydrolase Cel6A (formerly CBHII) has a tunnel shaped active site with four internal subsites for the glucose units. We have predicted an additional ring stacking interaction for a sixth glucose moiety with a tryptophan residue (W272) found on the domain surface. Mutagenesis of this residue selectively impairs the enzyme function on crystalline cellulose but not on soluble or amorphous substrates. Our data shows that W272 forms an additional subsite at the entrance of the active site tunnel and suggests it has a specialised role in crystalline cellulose degradation, possibly in guiding a glucan chain into the tunnel. (C) 1998 Federation of European Biochemical Societies.

引用

页码：341 / 346

页数：6

共 34 条

[1] Identification of two functionally different classes of exocellulases [J].