PDBsum entry: 2rfw

Hydrolase

PDB-id: 2rfw

Main view

Contents

Description

Header details

Header records

References

PROCHECK

Protein chains

430 a.a. *

Waters ×689

* Residue conservation analysis

Tools

Clefts Calculation

Bottom view	Right view

PDB id:

2rfw

Name:

Hydrolase

Title:

Crystal structure of cellobiohydrolase from melanocarpus albomyces

Structure:

Cellulose 1,4-beta-cellobiosidase. Chain: a, b, c, d. Mutation: yes

Source:

Melanocarpus albomyces. Organism_taxid: 204285

UniProt:

Chains A, B, C, D: Q8J0K6 (Q8J0K6_MELAO)

Seq:

Struc:

Seq:

452 a.a.

Struc:

430 a.a.*

Key:	PfamA domain
Secondary structure	CATH domain

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme class:

E.C.3.2.1.91   [IntEnz]   [ExPASy]   [KEGG]   [BRENDA]

Reaction:

Hydrolysis of 1,4-beta-D-glucosidic linkages in cellulose and cellotetraose, releasing cellobiose from the non-reducing ends of the chains.

Resolution:

1.60Å

R-factor:

0.199

R-free:

0.243

Authors:

T.Parkkinen,A.Koivula,J.Vehmaanper,J.Rouvinen

Key ref:

T.Parkkinen et al. (2008). Crystal structures of Melanocarpus albomyces cellobiohydrolase Cel7B in complex with cello-oligomers show high flexibility in the substrate binding.. Protein Sci, 17, 1383-1394. [PubMed id: 18499583] [DOI: 10.1110/ps.034488.108]

Date:

02-Oct-07

Release date:

16-Sep-08

Related entries:

2rfy
2rfz
2rg0

Quick_links

Procheck

Surface

Key reference

DOI no: 10.1110/ps.034488.108

Protein Sci 17:1383-1394 (2008)

PubMed id: 18499583

Crystal structures of Melanocarpus albomyces cellobiohydrolase Cel7B in complex with cello-oligomers show high flexibility in the substrate binding.

T.Parkkinen, A.Koivula, J.Vehmaanperä, J.Rouvinen.

ABSTRACT

Cellobiohydrolase from Melanocarpus albomyces (Cel7B) is a thermostable, single-module, cellulose-degrading enzyme. It has relatively low catalytic activity under normal temperatures, which allows structural studies of the binding of unmodified substrates to the native enzyme. In this study, we have determined the crystal structure of native Ma Cel7B free and in complex with three different cello-oligomers: cellobiose (Glc(2)), cellotriose (Glc(3)), and cellotetraose (Glc(4)), at high resolution (1.6-2.1 A). In each case, four molecules were found in the asymmetric unit, which provided 12 different complex structures. The overall fold of the enzyme is characteristic of a glycoside hydrolase family 7 cellobiohydrolase, where the loops extending from the core beta-sandwich structure form a long tunnel composed of multiple subsites for the binding of the glycosyl units of a cellulose chain. The catalytic residues at the reducing end of the tunnel are conserved, and the mechanism is expected to be retaining similarly to the other family 7 members. The oligosaccharides in different complex structures occupied different subsite sets, which partly overlapped and ranged from -5 to +2. In four cellotriose and one cellotetraose complex structures, the cello-oligosaccharide also spanned over the cleavage site (-1/+1). There were surprisingly large variations in the amino acid side chain conformations and in the positions of glycosyl units in the different cello-oligomer complexes, particularly at subsites near the catalytic site. However, in each complex structure, all glycosyl residues were in the chair (4C(1)) conformation. Implications in relation to the complex structures with respect to the reaction mechanism are discussed.