Mechanistic insight into the substrate specificity of 1,2-β-oligoglucan phosphorylase from Lachnoclostridium phytofermentans
説明
<jats:title>Abstract</jats:title><jats:p>Glycoside phosphorylases catalyze the phosphorolysis of oligosaccharides into sugar phosphates. Recently, we found a novel phosphorylase acting on β-1,2-glucooligosaccharides with degrees of polymerization of 3 or more (1,2-β-oligoglucan phosphorylase, SOGP) in glycoside hydrolase family (GH) 94. Here, we characterized SOGP from <jats:italic>Lachnoclostridium phytofermentans</jats:italic> (LpSOGP) and determined its crystal structure. LpSOGP is a monomeric enzyme that contains a unique β-sandwich domain (Ndom1) at its N-terminus. Unlike the dimeric GH94 enzymes possessing catalytic pockets at their dimer interface, LpSOGP has a catalytic pocket between Ndom1 and the catalytic domain. In the complex structure of LpSOGP with sophorose, sophorose binds at subsites +1 to +2. Notably, the Glc moiety at subsite +1 is flipped compared with the corresponding ligands in other GH94 enzymes. This inversion suggests the great distortion of the glycosidic bond between subsites −1 and +1, which is likely unfavorable for substrate binding. Compensation for this disadvantage at subsite +2 can be accounted for by the small distortion of the glycosidic bond in the sophorose molecule. Therefore, the binding mode at subsites +1 and +2 defines the substrate specificity of LpSOGP, which provides mechanistic insights into the substrate specificity of a phosphorylase acting on β-1,2-glucooligosaccharides.</jats:p>
収録刊行物
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- Scientific Reports
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Scientific Reports 7 (1), 42671-, 2017-02-15
Springer Science and Business Media LLC
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キーワード
- Clostridium
- Models, Molecular
- Binding Sites
- Glycoside Hydrolases
- Biochemical Phenomena
- Protein Conformation
- Hydrogen Bonding
- Ligands
- Article
- Substrate Specificity
- Kinetics
- Structure-Activity Relationship
- Protein Domains
- Catalytic Domain
- Protein Interaction Domains and Motifs
- Amino Acid Sequence
- Mechanical Phenomena
- Protein Binding