Characterization of a novel type of glycogen-degrading amylopullulanase from Lactobacillus crispatus.
Appl Microbiol Biotechnol
; 106(11): 4053-4064, 2022 Jun.
Article
en En
| MEDLINE
| ID: mdl-35612627
ABSTRACT
Glycogen is one of the major carbohydrates utilized by the human vaginal microbiota, which is commonly dominated by Lactobacillus, especially L. crispatus. An in silico analysis predicted that a type I pullulanase was involved in glycogen degradation in L. crispatus. The biochemical and genetic properties of the pullulanase still need to be determined. Here, we de novo identified the glycogen (Glg)-utilization enzyme (named GlgU) from L. crispatus through a biochemical assay. GlgU was optimally active at acidic pH, approximately 4.0 ~ 4.5, and was able to hydrolyze glycogen into low-molecular-weight malto-oligosaccharides. Actually, GlgU was a type II pullulanase (amylopullulanase) with just one catalytic domain that possessed substrate specificity toward both α-1,4 and α-1,6-glucosidic bonds. Phylogenetically, GlgU was obviously divergent from the known amylases and pullulanases (including amylopullulanases) in lactobacilli. In addition, we confirmed the catalytic activity of glgU in a nonglycogen-utilizing lactobacilli strain, demonstrating the essential role of glgU in glycogen metabolism. Overall, this study characterized a novel type of amylopullulanases, contributing to the knowledge of the glycogen utilization mechanism of the dominant species of human vaginal microbiota. KEY POINTS ⢠GlgU was a type II pullulanase, not a type I pullulanase predicted before. ⢠GlgU was able to completely hydrolyze glycogen into malto-oligosaccharides. ⢠GlgU played a key role in the metabolism of extracellular glycogen.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Lactobacillus crispatus
Límite:
Female
/
Humans
Idioma:
En
Revista:
Appl Microbiol Biotechnol
Año:
2022
Tipo del documento:
Article
País de afiliación:
China