PDBsum entry 4n4b

Hydrolase

PDB id: 4n4b

Contents

Protein chain

319 a.a.

Ligands

EPE

TRS

1PE

Metals

_CA

Waters ×415

PDB id:

4n4b

Name:

Hydrolase

Title:

Crystal structure of the alpha-l-arabinofuranosidase paabf62a from podospora anserina

Structure:

Gh62 arabinofuranosidase. Chain: a. Synonym: alpha-l-arabinofuranosidase paabf62a. Engineered: yes

Source:

Podospora anserina. Organism_taxid: 5145. Strain: s mat+. Expressed in: pichia pastoris. Expression_system_taxid: 4922

Resolution:

1.44Å R-factor: 0.129 R-free: 0.152

Authors:

B.Siguier,C.Dumon,L.Mourey,S.Tranier

Key ref:

B.Siguier et al. (2014). First structural insights into α-L-arabinofuranosidases from the two GH62 glycoside hydrolase subfamilies. J Biol Chem, 289, 5261-5273. PubMed id: 24394409 DOI: 10.1074/jbc.M113.528133

Date:

08-Oct-13 Release date: 15-Jan-14

Protein chain

E2GHW5  (E2GHW5_PODAS) -  Alpha-L-arabinofuranosidase (Fragment) from Podospora anserina

Seq: 337 a.a.

Struc: 319 a.a.

Enzyme reactions

• Enzyme class: E.C.3.2.1.55 - non-reducing end alpha-L-arabinofuranosidase.
• Reaction: Hydrolysis of terminal non-reducing alpha-L-arabinofuranoside residues in alpha-L-arabinosides.

DOI no: 10.1074/jbc.M113.528133

J Biol Chem 289:5261-5273 (2014)

PubMed id: 24394409

First structural insights into α-L-arabinofuranosidases from the two GH62 glycoside hydrolase subfamilies.

B.Siguier, M.Haon, V.Nahoum, M.Marcellin, O.Burlet-Schiltz, P.M.Coutinho, B.Henrissat, L.Mourey, M.J.O'Donohue, J.G.Berrin, S.Tranier, C.Dumon.

ABSTRACT

α-l-Arabinofuranosidases are glycoside hydrolases that specifically hydrolyze non-reducing residues from arabinose-containing polysaccharides. In the case of arabinoxylans, which are the main components of hemicellulose, they are part of microbial xylanolytic systems and are necessary for complete breakdown of arabinoxylans. Glycoside hydrolase family 62 (GH62) is currently a small family of α-l-arabinofuranosidases that contains only bacterial and fungal members. Little is known about the GH62 mechanism of action, because only a few members have been biochemically characterized and no three-dimensional structure is available. Here, we present the first crystal structures of two fungal GH62 α-l-arabinofuranosidases from the basidiomycete Ustilago maydis (UmAbf62A) and ascomycete Podospora anserina (PaAbf62A). Both enzymes are able to efficiently remove the α-l-arabinosyl substituents from arabinoxylan. The overall three-dimensional structure of UmAbf62A and PaAbf62A reveals a five-bladed β-propeller fold that confirms their predicted classification into clan GH-F together with GH43 α-l-arabinofuranosidases. Crystallographic structures of the complexes with arabinose and cellotriose reveal the important role of subsites +1 and +2 for sugar binding. Intriguingly, we observed that PaAbf62A was inhibited by cello-oligosaccharides and displayed binding affinity to cellulose although no activity was observed on a range of cellulosic substrates. Bioinformatic analyses showed that UmAbf62A and PaAbf62A belong to two distinct subfamilies within the GH62 family. The results presented here provide a framework to better investigate the structure-function relationships within the GH62 family.