First Crystallographic Structure of a Xylanase from Glycoside Hydrolase Family 5: Implications for Catalysis
详细信息 查看全文
- 作者：Steven B. Larson ; John Day ; Ana Paulina Barba de la Rosa ; Noel T. Keen ; and Alexander McPherson
- 刊名：Biochemistry
- 出版年：2003
- 出版时间：July 22, 2003
- 年：2003
- 卷：42
- 期：28
- 页码：8411 - 8422
- 全文大小：520K
- 年卷期：v.42,no.28(July 22, 2003)
- ISSN：1520-4995
文摘
The room-temperature structure of xylanase (EC 3.2.1.8) from the bacterial plant pathogenErwinia chrysanthemi expressed in Escherichia coli, a 45 kDa, 413-amino acid protein belonging toglycoside hydrolase family 5, has been determined by multiple isomorphous replacement and refined toa resolution of 1.42 Å. This represents the first structure of a xylanase not belonging to either glycosidehydrolase family 10 or family 11. The enzyme is composed of two domains similar to most family 10xylanases and the 
-amylases. The catalytic domain (residues 46-315) has a (
/)8-barrel motif with abinding cleft along the C-terminal side of the -barrel. The catalytic residues, Glu165 and Glu253,determined by correspondence to other family 5 and family 10 glycoside hydrolases, lie inside this clefton the C-terminal ends of -strands 4 and 7, respectively, with an O
2···O1 distance of 4.22 Å. Thesmaller domain (residues 31-43 and 323-413) has a 9-barrel motif with five of the strands interfacingwith -helices 7 and 8 of the catalytic domain. The first 13 N-terminal residues form one -strand of thisdomain. Residues 44, 45, and 316-322 form the linkers between this domain and the catalytic domain.
-amylases. The catalytic domain (residues 46-315) has a (/)8-barrel motif with abinding cleft along the C-terminal side of the -barrel. The catalytic residues, Glu165 and Glu253,determined by correspondence to other family 5 and family 10 glycoside hydrolases, lie inside this clefton the C-terminal ends of -strands 4 and 7, respectively, with an O2···O1 distance of 4.22 Å. Thesmaller domain (residues 31-43 and 323-413) has a 9-barrel motif with five of the strands interfacingwith -helices 7 and 8 of the catalytic domain. The first 13 N-terminal residues form one -strand of thisdomain. Residues 44, 45, and 316-322 form the linkers between this domain and the catalytic domain.