PDBsum entry 2wnx

Hydrolase

PDB id: 2wnx

Contents

Protein chain

157 a.a. *

Ligands

SO4 ×3

FMT

Metals

_CA

Waters ×349

* Residue conservation analysis

PDB id:

2wnx

Name:

Hydrolase

Title:

3b' carbohydrate-binding module from the cel9v glycoside hydrolase from clostridium thermocellum

Structure:

Glycoside hydrolase, family 9. Chain: a. Fragment: carbohydrate-binding module3b', residues 731-888. Synonym: cel9v glycoside hydrolase. Engineered: yes

Source:

Clostridium thermocellum. Organism_taxid: 1515. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

1.31Å R-factor: 0.121 R-free: 0.154

Authors:

S.Petkun,S.Jindou,L.J.W.Shimon,E.A.Bayer,R.Lamed,F.Frolow

Key ref:

S.Petkun et al. (2010). Structure of a family 3b' carbohydrate-binding module from the Cel9V glycoside hydrolase from Clostridium thermocellum: structural diversity and implications for carbohydrate binding. Acta Crystallogr D Biol Crystallogr, 66, 33-43. PubMed id: 20057047

Date:

20-Jul-09 Release date: 29-Dec-09

Protein chain

A3DJ30  (A3DJ30_CLOTH) -  cellulase from Acetivibrio thermocellus (strain ATCC 27405 / DSM 1237 / JCM 9322 / NBRC 103400 / NCIMB 10682 / NRRL B-4536 / VPI 7372)

Seq: 961 a.a.

Struc: 157 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.2.1.4 - cellulase.
• Reaction: Endohydrolysis of 1,4-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans.

Acta Crystallogr D Biol Crystallogr 66:33-43 (2010)

PubMed id: 20057047

Structure of a family 3b' carbohydrate-binding module from the Cel9V glycoside hydrolase from Clostridium thermocellum: structural diversity and implications for carbohydrate binding.

S.Petkun, S.Jindou, L.J.Shimon, S.Rosenheck, E.A.Bayer, R.Lamed, F.Frolow.

ABSTRACT

Family 3 carbohydrate-binding modules (CBM3s) are associated with both cellulosomal scaffoldins and family 9 glycoside hydrolases (GH9s), which are multi-modular enzymes that act on cellulosic substrates. CBM3s bind cellulose. X-ray crystal structures of these modules have established an accepted cellulose-binding mechanism based on stacking interactions between the sugar rings of cellulose and a planar array of aromatic residues located on the CBM3 surface. These planar-strip residues are generally highly conserved, although some CBM3 sequences lack one or more of these residues. In particular, CBM3b' from Clostridium thermocellum Cel9V exhibits such sequence changes and fails to bind cellulosic substrates. A crystallographic investigation of CBM3b' has been initiated in order to understand the structural reason(s) for this inability. CBM3b' crystallized in space group C222(1) (diffraction was obtained to 2.0 A resolution in-house) with three independent molecules in the asymmetric unit and in space group P4(1)2(1)2 (diffraction was obtained to 1.79 A resolution in-house and to 1.30 A resolution at a synchrotron) with one molecule in the asymmetric unit. The molecular structure of Cel9V CBM3b' revealed that in addition to the loss of several cellulose-binding residues in the planar strip, changes in the backbone create a surface 'hump' which could interfere with the formation of cellulose-protein surface interactions and thus prevent binding to crystalline cellulose.