3KMV

Crystal structure of CBM42A from Clostridium thermocellum

3KMV の概要

• エントリーDOI: 10.2210/pdb3kmv/pdb
• 分子名称: Alpha-L-arabinofuranosidase B, GLYCEROL, FORMIC ACID, ... (6 entities in total)
• 機能のキーワード: protein:carboydrate interactions, carbohydrate-binding module, beta-trefoil fold, cbm42, sugar binding protein
• 由来する生物種: Clostridium thermocellum
• タンパク質・核酸の鎖数: 8
• 化学式量合計: 147807.20

構造登録者

Santos-Silva, T.,Alves, V.D.,Prates, J.A.M.,Fontes, C.M.G.A.,Romao, M.J. (登録日: 2009-11-11, 公開日: 2010-08-04, 最終更新日: 2023-09-06)

主引用文献

Ribeiro, T.,Santos-Silva, T.,Alves, V.D.,Dias, F.M.,Luis, A.S.,Prates, J.A.,Ferreira, L.M.,Romao, M.J.,Fontes, C.M.
Family 42 carbohydrate-binding modules display multiple arabinoxylan-binding interfaces presenting different ligand affinities.
Biochim.Biophys.Acta, 1804:2054-2062, 2010

PubMed Abstract: Enzymes that degrade plant cell wall polysaccharides display a modular architecture comprising a catalytic domain bound to one or more non-catalytic carbohydrate-binding modules (CBMs). CBMs display considerable variation in primary structure and are grouped into 59 sequence-based families organized in the Carbohydrate-Active enZYme (CAZy) database. Here we report the crystal structure of CtCBM42A together with the biochemical characterization of two other members of family 42 CBMs from Clostridium thermocellum. CtCBM42A, CtCBM42B and CtCBM42C bind specifically to the arabinose side-chains of arabinoxylans and arabinan, suggesting that various cellulosomal components are targeted to these regions of the plant cell wall. The structure of CtCBM42A displays a beta-trefoil fold, which comprises 3 sub-domains designated as alpha, beta and gamma. Each one of the three sub-domains presents a putative carbohydrate-binding pocket where an aspartate residue located in a central position dominates ligand recognition. Intriguingly, the gamma sub-domain of CtCBM42A is pivotal for arabinoxylan binding, while the concerted action of beta and gamma sub-domains of CtCBM42B and CtCBM42C is apparently required for ligand sequestration. Thus, this work reveals that the binding mechanism of CBM42 members is in contrast with that of homologous CBM13s where recognition of complex polysaccharides results from the cooperative action of three protein sub-domains presenting similar affinities.

PubMed: 20637315
DOI: 10.1016/j.bbapap.2010.07.006

実験手法

X-RAY DIFFRACTION (1.8 Å)