Global control of sugar metabolism: a gram-positive solution.

摘要: Bacteria utilise carbon sources in a strictly controlled hierarchical manner for which they have developed global control mechanisms that govern and coordinate source-specific regulation. This is achieved via catabolite repression (CCR), the result of transcriptional inducer exclusion. A common mechanism has evolved within group low-GC Gram-positive bacteria, including lactic acid bacteria. The seryl-phosphorylated form phosphotransferase HPr (HPr-ser-P) mediates CCR concert with pleiotropic regulator CcpA (catabolite protein) by repressing or activating catabolite-controlled genes. HPr-ser-P can concomitantly trigger exclusion inhibition carbohydrate-specific permeases. Histidyl-phosphorylated (HPr-his P) required transport many system (PTS). In addition, HPr-his P controls regulators catabolic enzymes phosphorylation. Thus, ratio P/HPr-ser-P determines utilisation particular source. mainly adjusted bifunctional kinase/phosphatase (HPrK/P), itself metabolic state cell. As result, information about cell combined signals scoring availability to fine-tune expression genes goal optimise growth rate any given mixture nutrients. review summarises current understanding regulation bacteria special emphasis on