PDBsum entry: 2ebs

Hydrolase

PDB id: 2ebs

Contents

Protein chains

770 a.a. *

Ligands

BGC-XYS-BGC-XYS-BGC-XYS-BGC ×2

Waters ×1078

* Residue conservation analysis

PDB id:

2ebs

Name:

Hydrolase

Title:

Crystal structure anaalysis of oligoxyloglucan reducing-end- specific cellobiohydrolase (oxg-rcbh) d465n mutant complexed with a xyloglucan heptasaccharide

Structure:

Oligoxyloglucan reducing end-specific cellobiohydrolase. Chain: a, b. Fragment: residues 1-789. Synonym: oxg-rcbh. Engineered: yes. Mutation: yes

Source:

Geotrichum sp. M128. Organism_taxid: 203496. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.40Å R-factor: 0.162 R-free: 0.219

Authors:

K.Yaoi,H.Kondo,A.Hiyoshi,N.Noro,H.Sugimoto,K.Miyazaki,Riken Structural Genomics/proteomics Initiative (Rsgi)

Key ref:

K.Yaoi et al. (2007). The Structural Basis for the Exo-mode of Action in GH74 Oligoxyloglucan Reducing End-specific Cellobiohydrolase. J Mol Biol, 370, 53-62. PubMed id: 17498741 DOI: 10.1016/j.jmb.2007.04.035

Date:

09-Feb-07 Release date: 26-Jun-07

Protein chains

Q8J0D2  (CBHRE_GEOS1) -  Oligoxyloglucan reducing end-specific cellobiohydrolase

Seq: 812 a.a.

Struc: 770 a.a.*

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

Enzyme reactions

• Enzyme class: E.C.3.2.1.150 - Oligoxyloglucan reducing-end-specific cellobiohydrolase.

 Gene Ontology (GO) functional annotation 

• Biological process: metabolic process (4 terms)
• Biochemical function: hydrolase activity (3 terms)

DOI no: 10.1016/j.jmb.2007.04.035

J Mol Biol 370:53-62 (2007)

PubMed id: 17498741

The Structural Basis for the Exo-mode of Action in GH74 Oligoxyloglucan Reducing End-specific Cellobiohydrolase.

K.Yaoi, H.Kondo, A.Hiyoshi, N.Noro, H.Sugimoto, S.Tsuda, Y.Mitsuishi, K.Miyazaki.

ABSTRACT

Oligoxyloglucan reducing end-specific cellobiohydrolase (OXG-RCBH) is a unique exo-beta-1,4-glucanase that belongs to glycoside hydrolase family 74. The enzyme recognizes the reducing end of xyloglucan oligosaccharides and releases two glucosyl residue segments from the reducing end of the main chain. Previously, we reported that OXG-RCBH consists of two seven-bladed beta-propeller domains. There is a large cleft between the two domains, and a unique loop encloses one side of the active site cleft. Here, we report the X-ray crystal structure of the OXG-RCBH-substrate complex determined to a resolution of 2.4 A. The substrate bound to the cleft, and its reducing end was arranged near the loop region that is believed to impart OXG-RCBH with its activity. We constructed a deletion mutant of the loop region and conducted a detailed analysis. A deletion mutant of the loop region showed endo-activity with altered substrate recognition. More specifically, cleavage occurred randomly instead of at specific sites, most likely due to the misalignment of the substrate within the subsite. We believe that the loop imparts unique substrate specificity with exo-mode hydrolysis in OXG-RCBH.

Selected figure(s)

Figure 1.

Figure 2.
Figure 2. The stereo view of the active site around −2 to +2. (a) OXG-RCBH with the substrate, XXXG. (b) Clostridium thermocellum Xgh74A with the substrate LGXX (PDB code: 2CN3). The substrates are colored yellow.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2007, 370, 53-62) copyright 2007.

Figures were selected by the author.