PDBsum entry: 3ez8

Hydrolase

PDB id: 3ez8

Contents

Protein chain

528 a.a. *

Ligands

MPD ×2

Metals

_CA ×2

_ZN

Waters ×380

* Residue conservation analysis

PDB id:

3ez8

Name:

Hydrolase

Title:

Crystal structure of endoglucanase cel9a from the thermoacidophilic alicyclobacillus acidocaldarius

Structure:

Cellulase. Chain: a. Fragment: ig-like module. Engineered: yes

Source:

Alicyclobacillus acidocaldarius. Bacillus acidocaldarius. Organism_taxid: 1388. Gene: cela. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.30Å R-factor: 0.197 R-free: 0.233

Authors:

J.H.Pereira,R.Sapra,B.Simmons,P.D.Adams

Key ref:

J.H.Pereira et al. (2009). Structure of endoglucanase Cel9A from the thermoacidophilic Alicyclobacillus acidocaldarius. Acta Crystallogr D Biol Crystallogr, 65, 744-750. PubMed id: 19622857 DOI: 10.1107/S0907444909012773

Date:

22-Oct-08 Release date: 04-Aug-09

Protein chain

Q9AJS0  (Q9AJS0_ALIAC) -  Cellulase

Seq: 537 a.a.

Struc: 528 a.a.

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.

 Gene Ontology (GO) functional annotation 

• Biological process: metabolic process (2 terms)
• Biochemical function: catalytic activity (5 terms)

DOI no: 10.1107/S0907444909012773

Acta Crystallogr D Biol Crystallogr 65:744-750 (2009)

PubMed id: 19622857

Structure of endoglucanase Cel9A from the thermoacidophilic Alicyclobacillus acidocaldarius.

J.H.Pereira, R.Sapra, J.V.Volponi, C.L.Kozina, B.Simmons, P.D.Adams.

ABSTRACT

The production of biofuels using biomass is an alternative route to support the growing global demand for energy and to also reduce the environmental problems caused by the burning of fossil fuels. Cellulases are likely to play an important role in the degradation of biomass and the production of sugars for subsequent fermentation to fuel. Here, the crystal structure of an endoglucanase, Cel9A, from Alicyclobacillus acidocaldarius (Aa_Cel9A) is reported which displays a modular architecture composed of an N-terminal Ig-like domain connected to the catalytic domain. This paper describes the overall structure and the detailed contacts between the two modules. Analysis suggests that the interaction involving the residues Gln13 (from the Ig-like module) and Phe439 (from the catalytic module) is important in maintaining the correct conformation of the catalytic module required for protein activity. Moreover, the Aa_Cel9A structure shows three metal-binding sites that are associated with the thermostability and/or substrate affinity of the enzyme.

Selected figure(s)

Figure 1.
Figure 1 Modular architecture of Aa_Cel9A. The N-terminal Ig-like module consists of six -strands, creating a -barrel structure. The catalytic module has an ( / )[6]-barrel motif formed by the inner -helices. The metal ions bound to Aa_Cel9A are shown as large spheres. The zinc ion and the two calcium ions are shown in green and yellow, respectively. N, amino-terminus; C, carboxyl-terminus.

Figure 3.
Figure 3 The coordination spheres of the metal-binding sites in Aa_Cel9A. (a) The zinc-binding site shows a tetrahedral coordination. (b, c) The two calcium-binding sites show polyhedral coordination formed exclusively from O atoms. For a complete discussion, see the main text.

The above figures are reprinted by permission from the IUCr: Acta Crystallogr D Biol Crystallogr (2009, 65, 744-750) copyright 2009.

Figures were selected by an automated process.