5FU3

The complexity of the Ruminococcus flavefaciens cellulosome reflects an expansion in glycan recognition

5FU3 の概要

• エントリーDOI: 10.2210/pdb5fu3/pdb
• 関連するPDBエントリー: 5FU2 5FU4 5FU5
• 関連するBIRD辞書のPRD_ID: PRD_900021
• 分子名称: CBM74-RFGH5, beta-D-glucopyranose-(1-4)-beta-D-glucopyranose-(1-4)-beta-D-glucopyranose, SODIUM ION, ... (4 entities in total)
• 機能のキーワード: cellulosome, carbohydrate binding module, ruminoccocus flavefaciens, endoglucanase cel5a, sugar binding protein
• 由来する生物種: RUMINOCOCCUS FLAVEFACIENS
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 24701.67

構造登録者

Basle, A.,Luis, A.S.,Venditto, I.,Gilbert, H.J. (登録日: 2016-01-20, 公開日: 2016-06-22, 最終更新日: 2024-01-10)

主引用文献

Venditto, I.,Luis, A.S.,Rydahl, M.,Schuckel, J.,Fernandes, V.O.,Vidal-Melgosa, S.,Bule, P.,Goyal, A.,Pires, V.M.R.,Dourado, C.G.,Ferreira, L.M.A.,Coutinho, P.M.,Henrissat, B.,Knox, J.P.,Basle, A.,Najmudin, S.,Gilbert, H.J.,Willats, W.G.T.,Fontes, C.M.G.A.
Complexity of the Ruminococcus Flavefaciens Cellulosome Reflects an Expansion in Glycan Recognition.
Proc.Natl.Acad.Sci.USA, 113:7136-, 2016

PubMed Abstract: The breakdown of plant cell wall (PCW) glycans is an important biological and industrial process. Noncatalytic carbohydrate binding modules (CBMs) fulfill a critical targeting function in PCW depolymerization. Defining the portfolio of CBMs, the CBMome, of a PCW degrading system is central to understanding the mechanisms by which microbes depolymerize their target substrates. Ruminococcus flavefaciens, a major PCW degrading bacterium, assembles its catalytic apparatus into a large multienzyme complex, the cellulosome. Significantly, bioinformatic analyses of the R. flavefaciens cellulosome failed to identify a CBM predicted to bind to crystalline cellulose, a key feature of the CBMome of other PCW degrading systems. Here, high throughput screening of 177 protein modules of unknown function was used to determine the complete CBMome of R. flavefaciens The data identified six previously unidentified CBM families that targeted β-glucans, β-mannans, and the pectic polysaccharide homogalacturonan. The crystal structures of four CBMs, in conjunction with site-directed mutagenesis, provide insight into the mechanism of ligand recognition. In the CBMs that recognize β-glucans and β-mannans, differences in the conformation of conserved aromatic residues had a significant impact on the topology of the ligand binding cleft and thus ligand specificity. A cluster of basic residues in CBM77 confers calcium-independent recognition of homogalacturonan, indicating that the carboxylates of galacturonic acid are key specificity determinants. This report shows that the extended repertoire of proteins in the cellulosome of R. flavefaciens contributes to an extended CBMome that supports efficient PCW degradation in the absence of CBMs that specifically target crystalline cellulose.

PubMed: 27298375
DOI: 10.1073/PNAS.1601558113

実験手法

X-RAY DIFFRACTION (1.61 Å)