Journal:Acta Cryst D:S205979832100677X

A GH13 α-glucosidase from Weissella cibaria uncommonly acts on short-chain maltooligosaccharides

Karan Wangpaiboon, Pasunee Laohawuttichai, Sun-Yong Kim, Tomoyuki Mori, Santhana Nakapong, Rath Pichyangkura, Piamsook Pongsawasdi, Toshio Hakoshima and Kuakarun Krusong ^[1]

Molecular Tour
α-Glucosidase (E.C.3.2.1.20) is a carbohydrate-hydrolyzing enzyme, which generally cleaves α-1,4 glycosidic bonds of oligosaccharides and starch from the non-reducing ends. However, α-glucosidase from Weissella cibaria BBK-1 (WcAG) exhibited distinct hydrolysis activity against α-1,4 linkages of short chain oligosaccharides from the reducing end. It prefers to hydrolyse and , while it cannot hydrolyse cyclic oligosaccharides and polysaccharides. WcAG formed a homodimer, of which the N-terminal domain of one monomer orientated in proximity to the catalytic domain of another, creating the substrate-binding groove. The active site of WcAG was naturally designed to fit perfectly with maltotriose. The Arg-Glu salt bridge gate (R176-E296) in front of the active site modulates the substrate specificity of WcAG.

Ligand binding sites:

• , PDB ID: 7d9b.
• , PDB ID: 7d9c.
• , PDB ID: 7dcg.
• , PDB ID: 7dch.
• , PDB ID: 7ehh.
• , PDB ID: 7ehi.

(grey) (PDB ID: 7ehi) is clearly observed by superimposition with maltotriose in WcAG structure (cyan) (PDB ID: 7dcg).

References

1. ↑ Wangpaiboon K, Laohawuttichai P, Kim SY, Mori T, Nakapong S, Pichyangkura R, Pongsawasdi P, Hakoshima T, Krusong K. A GH13 alpha-glucosidase from Weissella cibaria uncommonly acts on short-chain maltooligosaccharides. Acta Crystallogr D Struct Biol. 2021 Aug 1;77(Pt 8):1064-1076. doi:, 10.1107/S205979832100677X. Epub 2021 Jul 29. PMID:34342279 doi:http://dx.doi.org/10.1107/S205979832100677X