PDBsum entry 3ez8

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protein ligands metals links
Hydrolase PDB id
Protein chain
528 a.a. *
MPD ×2
_CA ×2
Waters ×380
* Residue conservation analysis
PDB id:
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.
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
22-Oct-08     Release date:   04-Aug-09    
Go to PROCHECK summary

Protein chain
Pfam   ArchSchema ?
Q9AJS0  (Q9AJS0_ALIAC) -  Cellulase
537 a.a.
528 a.a.
Key:    PfamA domain  Secondary structure  CATH domain

 Enzyme reactions 
   Enzyme class: E.C.  - Cellulase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: Endohydrolysis of 1,4-beta-D-glucosidic linkages in cellulose, lichenin and cereal beta-D-glucans.
 Gene Ontology (GO) functional annotation 
  GO annot!
  Biological process     metabolic process   2 terms 
  Biochemical function     catalytic activity     6 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.
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.  

Literature references that cite this PDB file's key reference

  PubMed id Reference
21098515 Y.Honda, N.Shimaya, K.Ishisaki, M.Ebihara, and H.Taniguchi (2011).
Elucidation of exo-{beta}-D-glucosaminidase activity of a family 9 glycoside hydrolase (PBPRA0520) from Photobacterium profundum SS9.
  Glycobiology, 21, 503-511.  
20169343 Y.Bai, J.Wang, Z.Zhang, P.Shi, H.Luo, H.Huang, C.Luo, and B.Yao (2010).
A novel family 9 beta-1,3(4)-glucanase from thermoacidophilic Alicyclobacillus sp. A4 with potential applications in the brewing industry.
  Appl Microbiol Biotechnol, 87, 251-259.  
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