論文 - 詳細
| RRC ID | 66764 |
|---|---|
| 著者 | Saito K, Viborg AH, Sakamoto S, Arakawa T, Yamada C, Fujita K, Fushinobu S. |
| タイトル | Crystal structure of β-L-arabinobiosidase belonging to glycoside hydrolase family 121. |
| ジャーナル | PLoS One |
| Abstract |
Enzymes acting on α-L-arabinofuranosides have been extensively studied; however, the structures and functions of β-L-arabinofuranosidases are not fully understood. Three enzymes and an ABC transporter in a gene cluster of Bifidobacterium longum JCM 1217 constitute a degradation and import system of β-L-arabinooligosaccharides on plant hydroxyproline-rich glycoproteins. An extracellular β-L-arabinobiosidase (HypBA2) belonging to the glycoside hydrolase (GH) family 121 plays a key role in the degradation pathway by releasing β-1,2-linked arabinofuranose disaccharide (β-Ara2) for the specific sugar importer. Here, we present the crystal structure of the catalytic region of HypBA2 as the first three-dimensional structure of GH121 at 1.85 Å resolution. The HypBA2 structure consists of a central catalytic (α/α)6 barrel domain and two flanking (N- and C-terminal) β-sandwich domains. A pocket in the catalytic domain appears to be suitable for accommodating the β-Ara2 disaccharide. Three acidic residues Glu383, Asp515, and Glu713, located in this pocket, are completely conserved among all members of GH121; site-directed mutagenesis analysis showed that they are essential for catalytic activity. The active site of HypBA2 was compared with those of structural homologs in other GH families: GH63 α-glycosidase, GH94 chitobiose phosphorylase, GH142 β-L-arabinofuranosidase, GH78 α-L-rhamnosidase, and GH37 α,α-trehalase. Based on these analyses, we concluded that the three conserved residues are essential for catalysis and substrate binding. β-L-Arabinobiosidase genes in GH121 are mainly found in the genomes of bifidobacteria and Xanthomonas species, suggesting that the cleavage and specific import system for the β-Ara2 disaccharide on plant hydroxyproline-rich glycoproteins are shared in animal gut symbionts and plant pathogens. |
| 巻・号 | 15(6) |
| ページ | e0231513 |
| 公開日 | 2020-1-1 |
| DOI | 10.1371/journal.pone.0231513 |
| PII | PONE-D-20-08343 |
| PMID | 32479540 |
| PMC | PMC7263609 |
| MeSH | Amino Acid Sequence Bifidobacterium longum / enzymology Catalytic Domain Crystallography, X-Ray Glycoside Hydrolases / chemistry* Glycoside Hydrolases / genetics Models, Molecular Mutagenesis, Site-Directed Sequence Alignment |
| オルトメトリクス指標 |
オルトメトリクス指標項目
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| 最多言及媒体 | X(Twitter) |
| 各媒体での言及数の合計 | 4 |
| 過去6か月間でのオルトメトリクス指標の変動値 | 0.0 |
| リソース情報 | |
| 一般微生物 | JCM1217 |