PDBsum entry 4fmv

Hydrolase

PDB id: 4fmv

Contents

Protein chain

386 a.a.

Waters ×212

PDB id:

4fmv

Name:

Hydrolase

Title:

Crystal structure analysis of a gh30 endoxylanase from clostridium papyrosolvens c71

Structure:

Glucuronoarabinoxylan endo-1,4-beta-xylanase. Chain: a. Engineered: yes

Source:

Clostridium papyrosolvens. Organism_taxid: 588581. Strain: dsm2782. Gene: cpap_2855. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.01Å R-factor: 0.166 R-free: 0.200

Authors:

E.B.Bales,J.K.Smith,F.J.St John,J.C.Hurlbert

Key ref:

F.J.St John et al. (2014). A novel member of glycoside hydrolase family 30 subfamily 8 with altered substrate specificity. Acta Crystallogr D Biol Crystallogr, 70, 2950-2958. PubMed id: 25372685 DOI: 10.1107/S1399004714019531

Date:

18-Jun-12 Release date: 19-Jun-13

Protein chain

F1TBY8  (F1TBY8_9FIRM) -  cellulase from Ruminiclostridium papyrosolvens DSM 2782

Seq: 628 a.a.

Struc: 386 a.a.*

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

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.

DOI no: 10.1107/S1399004714019531

Acta Crystallogr D Biol Crystallogr 70:2950-2958 (2014)

PubMed id: 25372685

A novel member of glycoside hydrolase family 30 subfamily 8 with altered substrate specificity.

F.J.St John, D.Dietrich, C.Crooks, E.Pozharski, J.M.González, E.Bales, K.Smith, J.C.Hurlbert.

ABSTRACT

Endoxylanases classified into glycoside hydrolase family 30 subfamily 8 (GH30-8) are known to hydrolyze the hemicellulosic polysaccharide glucuronoxylan (GX) but not arabinoxylan or neutral xylooligosaccharides. This is owing to the specificity of these enzymes for the α-1,2-linked glucuronate (GA) appendage of GX. Limit hydrolysis of this substrate produces a series of aldouronates each containing a single GA substituted on the xylose penultimate to the reducing terminus. In this work, the structural and biochemical characterization of xylanase 30A from Clostridium papyrosolvens (CpXyn30A) is presented. This xylanase possesses a high degree of amino-acid identity to the canonical GH30-8 enzymes, but lacks the hallmark β8-α8 loop region which in part defines the function of this GH30 subfamily and its role in GA recognition. CpXyn30A is shown to have a similarly low activity on all xylan substrates, while hydrolysis of xylohexaose revealed a competing transglycosylation reaction. These findings are directly compared with the model GH30-8 enzyme from Bacillus subtilis, XynC. Despite its high sequence identity to the GH30-8 enzymes, CpXyn30A does not have any apparent specificity for the GA appendage. These findings confirm that the typically conserved β8-α8 loop region of these enzymes influences xylan substrate specificity but not necessarily β-1,4-xylanase function.