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. . Blue represents Domain A, whereas Domain B, C, and N are shown in yellow, red, and green, respectively. Calcium ion is in magenta.
. Lighter colors represent different subunit of dimer.
WcAG formed a , creating the substrate-binding groove. The residues near the dimer interface are shown in dark blue and deep sky blue sticks, while the maltotriose and catalytic residues are represented by yellow and magenta, respectively. 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:
The carbon, nitrogen and oxygen atoms of the bound ligands are displayed in
cyan/yellow, blue and red, respectively. The three catalytic residues are shown in salmon sticks.
(grey) (PDB ID: 7ehi) is clearly observed by superimposition with maltotriose in WcAG structure (cyan) (PDB ID: 7dcg).
References
- ↑ 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
