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The glgB-encoded glycogen branching enzyme is essential for glycogen accumulation in Corynebacterium glutamicum
- Source :
- Microbiology. 157:3243-3251
- Publication Year :
- 2011
- Publisher :
- Microbiology Society, 2011.
-
Abstract
- Corynebacterium glutamicum transiently accumulates glycogen as carbon capacitor during the early exponential growth phase in media containing carbohydrates. In some bacteria glycogen is synthesized by the consecutive action of ADP-glucose pyrophosphorylase (GlgC), glycogen synthase (GlgA) and glycogen branching enzyme (GlgB). GlgC and GlgA of C. glutamicum have been shown to be necessary for glycogen accumulation in this organism. However, although cg1381 has been annotated as the putative C. glutamicum glgB gene, cg1381 and its gene product have not been characterized and their role in transient glycogen accumulation has not yet been investigated. We show here that the cg1381 gene product of C. glutamicum catalyses the formation of α-1,6-glycosidic bonds in polysaccharides and thus represents a glycogen branching enzyme. RT-PCR experiments revealed glgB to be co-transcribed with glgE, probably encoding a maltosyltransferase. Promoter activity assays with the glgE promoter region revealed carbon-source-dependent expression of the glgEB operon. Characterization of the growth and glycogen content of glgB-deficient and glgB-overexpressing strains showed that the glycogen branching enzyme GlgB is essential for glycogen formation in C. glutamicum. Taken together these results suggest that an interplay of the enzymes GlgC, GlgA and GlgB is not essential for growth, but is required for synthesis of the transient carbon capacitor glycogen in C. glutamicum.
- Subjects :
- chemistry.chemical_classification
biology
Glycogen
Operon
Gene Expression Regulation, Bacterial
Polysaccharide
Microbiology
Glycogen debranching enzyme
Corynebacterium glutamicum
Gene product
chemistry.chemical_compound
Glucose
Bacterial Proteins
chemistry
Biochemistry
1,4-alpha-Glucan Branching Enzyme
Glycogen branching enzyme
biology.protein
Promoter Regions, Genetic
Glycogen synthase
Subjects
Details
- ISSN :
- 14652080 and 13500872
- Volume :
- 157
- Database :
- OpenAIRE
- Journal :
- Microbiology
- Accession number :
- edsair.doi.dedup.....4816bf7c3a59191576957ee1448047b1