The ADP-glucose pyrophosphorylase from Streptococcus mutans provides evidence for the regulation of polysaccharide biosynthesis in Firmicutes

Autor: Asención Diez, Matías Damián, Demonte, Ana María Magdalena, Guerrero, Sergio Adrian, Ballicora, Miguel A., Iglesias, Alberto Alvaro
Jazyk: angličtina
Rok vydání: 2013
Předmět:
Zdroj: CONICET Digital (CONICET)
Consejo Nacional de Investigaciones Científicas y Técnicas
instacron:CONICET
DOI: 10.1111/mmi.12413/abstract
Popis: Streptococcus mutans is the leading cause of dental caries worldwide. The bacterium accumulates a glycogen-like internal polysaccharide, which mainly contributes to its carionegic capacity. S. mutans has two genes (glgC and glgD) respectively encoding putative ADP-glucose pyrophosphorylases (ADP-Glc PPase), a key enzyme for glycogen synthesis in most bacteria. Herein, we report the molecular cloning and recombinant expression of both genes (separately or together) followed by the characterization of the respective enzymes. When expressed individually GlgC had ADP-Glc PPase activity, whereas GlgD was inactive. Interestingly, the coexpressed GlgC/GlgD protein was one order of magnitude more active than GlgC alone. Kinetic characterization of GlgC and GlgC/GlgD pointed out remarkable differences between them. Fructose-1,6-bis-phosphate activated GlgC by twofold, but had no effect on GlgC/GlgD. Conversely, phospho-enol-pyruvate and inorganic salts inhibited GlgC/GlgD without affecting GlgC. However, in the presence of fructose-1,6-bis-phosphate GlgC acquired a GlgC/GlgD-like behaviour, becoming sensitive to the stated inhibitors. Results indicate that S. mutans ADP-Glc PPase is an allosteric regulatory enzyme exhibiting sensitivity to modulation by key intermediates of carbohydrates metabolism in the cell. The particular regulatory properties of the S. mutans enzyme agree with phylogenetic analysis, where GlgC and GlgD proteins found in other Firmicutes arrange in distinctive clusters. Fil: Asención Diez, Matías Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentina. Loyola University Chicago. Department of Chemistry and Biochemistry; Estados Unidos Fil: Demonte, Ana María Magdalena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentina Fil: Guerrero, Sergio Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentina Fil: Ballicora, Miguel A.. Loyola University Chicago. Department of Chemistry and Biochemistry; Estados Unidos Fil: Iglesias, Alberto Alvaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentina
Databáze: OpenAIRE
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