6EUJ

The GH43, Beta 1,3 Galactosidase, BT0265

6EUJ の概要

• エントリーDOI: 10.2210/pdb6euj/pdb
• 分子名称: Beta-glucanase (1 entity in total)
• 機能のキーワード: arabiogalactan, gh43, beta 1, 3 galactosidase, hydrolase
• 由来する生物種: Bacteroides thetaiotaomicron (strain ATCC 29148 / DSM 2079 / NCTC 10582 / E50 / VPI-5482)
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 218685.53

構造登録者

Cartmell, A.,Gilbert, H.J. (登録日: 2017-10-30, 公開日: 2018-10-17, 最終更新日: 2024-10-23)

主引用文献

Cartmell, A.,Munoz-Munoz, J.,Briggs, J.A.,Ndeh, D.A.,Lowe, E.C.,Basle, A.,Terrapon, N.,Stott, K.,Heunis, T.,Gray, J.,Yu, L.,Dupree, P.,Fernandes, P.Z.,Shah, S.,Williams, S.J.,Labourel, A.,Trost, M.,Henrissat, B.,Gilbert, H.J.
A surface endogalactanase in Bacteroides thetaiotaomicron confers keystone status for arabinogalactan degradation.
Nat Microbiol, 3:1314-1326, 2018

PubMed Abstract: Glycans are major nutrients for the human gut microbiota (HGM). Arabinogalactan proteins (AGPs) comprise a heterogenous group of plant glycans in which a β1,3-galactan backbone and β1,6-galactan side chains are conserved. Diversity is provided by the variable nature of the sugars that decorate the galactans. The mechanisms by which nutritionally relevant AGPs are degraded in the HGM are poorly understood. Here we explore how the HGM organism Bacteroides thetaiotaomicron metabolizes AGPs. We propose a sequential degradative model in which exo-acting glycoside hydrolase (GH) family 43 β1,3-galactanases release the side chains. These oligosaccharide side chains are depolymerized by the synergistic action of exo-acting enzymes in which catalytic interactions are dependent on whether degradation is initiated by a lyase or GH. We identified two GHs that establish two previously undiscovered GH families. The crystal structures of the exo-β1,3-galactanases identified a key specificity determinant and departure from the canonical catalytic apparatus of GH43 enzymes. Growth studies of Bacteroidetes spp. on complex AGP revealed 3 keystone organisms that facilitated utilization of the glycan by 17 recipient bacteria, which included B. thetaiotaomicron. A surface endo-β1,3-galactanase, when engineered into B. thetaiotaomicron, enabled the bacterium to utilize complex AGPs and act as a keystone organism.

PubMed: 30349080
DOI: 10.1038/s41564-018-0258-8

実験手法

X-RAY DIFFRACTION (2.75 Å)