Identification and characterization of extracellular GH3 β-glucosidase from the pink snow mold fungus, Microdochium nivale

Biosci Biotechnol Biochem. 2023 Jun 23;87(7):707-716. doi: 10.1093/bbb/zbad044.

Abstract

Glycoside hydrolase family 3 (GH3) β-glucosidase exists in many filamentous fungi. In phytopathogenic fungi, it is involved in fungal growth and pathogenicity. Microdochium nivale is a severe phytopathogenic fungus of grasses and cereals and is the causal agent of pink snow mold, but its β-glucosidase has not been identified. In this study, a GH3 β-glucosidase of M. nivale (MnBG3A) was identified and characterized. Among various p-nitrophenyl β-glycosides, MnBG3A showed activity on d-glucoside (pNP-Glc) and slight activity on d-xyloside. In the pNP-Glc hydrolysis, substrate inhibition occurred (Kis = 1.6 m m), and d-glucose caused competitive inhibition (Ki = 0.5 m m). MnBG3A acted on β-glucobioses with β1-3, -6, -4, and -2 linkages, in descending order of kcat/Km. In contrast, the regioselectivity for newly formed products was limited to β1-6 linkage. MnBG3A has similar features to those of β-glucosidases from Aspergillus spp., but higher sensitivity to inhibitory effects.

Keywords: Microdochium nivale; glycoside hydrolase family 3; substrate specificity; transglucosylation; β-glucosidase.

MeSH terms

  • Fungi / metabolism
  • Glycoside Hydrolases*
  • Glycosides / chemistry
  • Kinetics
  • Substrate Specificity
  • beta-Glucosidase* / genetics
  • beta-Glucosidase* / metabolism

Substances

  • Glycoside Hydrolases
  • beta-Glucosidase
  • Glycosides

Supplementary concepts

  • Microdochium nivale

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