PDBsum entry 1e8r

Hydrolase

PDB id: 1e8r

Contents

Protein chain

50 a.a. *

* Residue conservation analysis

References listed in PDB file

Key reference

• Title: Solution structure of the cbm10 cellulose binding module from pseudomonas xylanase a.
• Authors: S.Raghothama, P.J.Simpson, L.Szabó, T.Nagy, H.J.Gilbert, M.P.Williamson.
• Ref.: Biochemistry, 2000, 39, 978-984. [DOI no: 10.1021/bi992163+]
• PubMed id: 10653641

Abstract

Plant cell wall hydrolases generally have a modular structure consisting of a catalytic domain linked to one or more noncatalytic carbohydrate-binding modules (CBMs), whose common function is to attach the enzyme to the polymeric substrate. Xylanase A from Pseudomonas fluorescens subsp. cellulosa (Pf Xyn10A) consists of a family 10 catalytic domain, an N-terminal family IIa cellulose-binding module, and an internal family 10 cellulose-binding module. The structure of the 45-residue family 10 CBM has been determined in solution using NMR. It consists of two antiparallel beta-sheets, one with two strands and one with three, with a short alpha-helix across one face of the three-stranded sheet. There is a high density of aromatic residues on one side of the protein, including three aromatic residues (Tyr8, Trp22, and Trp24), which are exposed and form a flat surface on one face, in a classical polysaccharide-binding arrangement. The fold is closely similar to that of the oligonucleotide/oligosaccharide-binding (OB) fold, but appears to have arisen by convergent evolution, because there is no sequence similarity, and the presumed binding sites are on different faces.