4YHE

NATIVE BACTEROIDETES-AFFILIATED GH5 CELLULASE LINKED WITH A POLYSACCHARIDE UTILIZATION LOCUS

4YHE の概要

• エントリーDOI: 10.2210/pdb4yhe/pdb
• 分子名称: GH5 (2 entities in total)
• 機能のキーワード: beta alpha barrel, glycoside hydrolase, metagenomics, hydrolase
• 由来する生物種: Bacteroidetes bacterium AC2a
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 87363.27

構造登録者

Naas, A.E.,MacKenzie, A.K.,Dalhus, B.,Eijsink, V.G.H.,Pope, P.B. (登録日: 2015-02-27, 公開日: 2015-05-20, 最終更新日: 2024-05-08)

主引用文献

Naas, A.E.,MacKenzie, A.K.,Dalhus, B.,Eijsink, V.G.,Pope, P.B.
Structural Features of a Bacteroidetes-Affiliated Cellulase Linked with a Polysaccharide Utilization Locus.
Sci Rep, 5:11666-11666, 2015

PubMed Abstract: Previous gene-centric analysis of a cow rumen metagenome revealed the first potentially cellulolytic polysaccharide utilization locus, of which the main catalytic enzyme (AC2aCel5A) was identified as a glycoside hydrolase (GH) family 5 endo-cellulase. Here we present the 1.8 Å three-dimensional structure of AC2aCel5A, and characterization of its enzymatic activities. The enzyme possesses the archetypical (β/α)8-barrel found throughout the GH5 family, and contains the two strictly conserved catalytic glutamates located at the C-terminal ends of β-strands 4 and 7. The enzyme is active on insoluble cellulose and acts exclusively on linear β-(1,4)-linked glucans. Co-crystallization of a catalytically inactive mutant with substrate yielded a 2.4 Å structure showing cellotriose bound in the -3 to -1 subsites. Additional electron density was observed between Trp178 and Trp254, two residues that form a hydrophobic "clamp", potentially interacting with sugars at the +1 and +2 subsites. The enzyme's active-site cleft was narrower compared to the closest structural relatives, which in contrast to AC2aCel5A, are also active on xylans, mannans and/or xyloglucans. Interestingly, the structure and function of this enzyme seem adapted to less-substituted substrates such as cellulose, presumably due to the insufficient space to accommodate the side-chains of branched glucans in the active-site cleft.

PubMed: 26133573
DOI: 10.1038/srep11666

実験手法

X-RAY DIFFRACTION (1.85 Å)