PDBsum entry: 1q9h

Hydrolase

PDB id: 1q9h

Contents

Protein chain

430 a.a. *

Ligands

NAG-NAG

NAG

Waters ×254

* Residue conservation analysis

PDB id:

1q9h

Name:

Hydrolase

Title:

3-dimensional structure of native cel7a from talaromyces eme

Structure:

Cellobiohydrolase i catalytic domain. Chain: a. Fragment: n-acetylglucosamine. Ec: 3.2.1.91

Source:

Talaromyces emersonii. Organism_taxid: 68825. Strain: cbs814.70. Other_details: thermophilic fungus

Resolution:

2.35Å R-factor: 0.165 R-free: 0.229

Authors:

A.Grassick,R.Thompson,P.G.Murray,C.M.Collins,L.Byrnes,M.G.Tu G.Birrane,T.M.Higgins

Key ref:

A.Grassick et al. (2004). Three-dimensional structure of a thermostable native cellobiohydrolase, CBH IB, and molecular characterization of the cel7 gene from the filamentous fungus, Talaromyces emersonii. Eur J Biochem, 271, 4495-4506. PubMed id: 15560790 DOI: 10.1111/j.1432-1033.2004.04409.x

Date:

25-Aug-03 Release date: 09-Nov-04

Protein chain

Q8TFL9  (Q8TFL9_TALEM) -  Cellobiohydrolase 1 catalytic domain

Seq: 455 a.a.

Struc: 430 a.a.*

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

Enzyme reactions

• Enzyme class: E.C.3.2.1.91 - Cellulose 1,4-beta-cellobiosidase (non-reducing end).
• Reaction: Hydrolysis of 1,4-beta-D-glucosidic linkages in cellulose and cellotetraose, releasing cellobiose from the non-reducing ends of the chains.

 Gene Ontology (GO) functional annotation 

• Biological process: metabolic process (2 terms)
• Biochemical function: hydrolase activity (4 terms)

DOI no: 10.1111/j.1432-1033.2004.04409.x

Eur J Biochem 271:4495-4506 (2004)

PubMed id: 15560790

Three-dimensional structure of a thermostable native cellobiohydrolase, CBH IB, and molecular characterization of the cel7 gene from the filamentous fungus, Talaromyces emersonii.

A.Grassick, P.G.Murray, R.Thompson, C.M.Collins, L.Byrnes, G.Birrane, T.M.Higgins, M.G.Tuohy.

ABSTRACT

The X-ray structure of native cellobiohydrolase IB (CBH IB) from the filamentous fungus Talaromyces emersonii, PDB 1Q9H, was solved to 2.4 A by molecular replacement. 1Q9H is a glycoprotein that consists of a large, single domain with dimensions of approximately 60 A x 40 A x 50 A and an overall beta-sandwich structure, the characteristic fold of Family 7 glycosyl hydrolases (GH7). It is the first structure of a native glycoprotein and cellulase from this thermophilic eukaryote. The long cellulose-binding tunnel seen in GH7 Cel7A from Trichoderma reesei is conserved in 1Q9H, as are the catalytic residues. As a result of deletions and other changes in loop regions, the binding and catalytic properties of T. emersonii 1Q9H are different. The gene (cel7) encoding CBH IB was isolated from T. emersonii and expressed heterologously with an N-terminal polyHis-tag, in Escherichia coli. The deduced amino acid sequence of cel7 is homologous to fungal cellobiohydrolases in GH7. The recombinant cellobiohydrolase was virtually inactive against methylumberiferyl-cellobioside and chloronitrophenyl-lactoside, but partial activity could be restored after refolding of the urea-denatured enzyme. Profiles of cel7 expression in T. emersonii, investigated by Northern blot analysis, revealed that expression is regulated at the transcriptional level. Putative regulatory element consensus sequences for cellulase transcription factors have been identified in the upstream region of the cel7 genomic sequence.

Selected figure(s)

Figure 3.
Fig. 3. Electron maps at the two N-glycosylation sites. (A) Asn267 with two GlcNAc (2-amino-2-N-acetylamino-D-glucose) residues. (B) Asn431 with one GlcNAc residue.

Figure 7.
Fig. 7. C-alpha trace of 1Q9H(yellow) superimposed on the C-alpha trace of 5 Cel(white), illustrating the more open active site of 1Q9H. The sugar residues are superimposed in blue. The catalytic residues are shown in red. The figure was drawn by using TURBO.

The above figures are reprinted by permission from the Federation of European Biochemical Societies: Eur J Biochem (2004, 271, 4495-4506) copyright 2004.

Figures were selected by an automated process.