Substrate induction and glucose repression of maltose utilization by Streptomyces coelicolor A3(2) is controlled by malR, a member of the lacI–galR family of regulatory genes

Abstract

SummarymalR of Streptomyces coelicolor A3(2) encodes a homologue of the LacI/GalR family of repressor proteins, and is divergently transcribed from the malEFG gene cluster, which encodes components of an ATPdependent transport system that is required for maltose utilization. Transcription of malE was induced by maltose and repressed by glucose. Disruption or deletion of malR resulted in constitutive, glucoseinsensitive malE transcription at a level markedly above that observed in the parental malR þ strain, and overproduction of MalR prevented growth on maltose as carbon source. Consequently, MalR plays a crucial role in both substrate induction and glucose repression of maltose utilization. malR is expressed from a single promoter with transcription initiating at the first G of the predicted GTG translation start codon.

How Phosphotransferase System-Related Protein Phosphorylation Regulates Carbohydrate Metabolism in Bacteria

“…Nevertheless, the uptake of fructose will lower the amount of PϳEI and PϳHPr and consequently will also lower the amount of PϳEIIA Glc . Although the main uptake system for glucose in S. coelicolor is GlcP, a non-PTS permease of the major facilitator superfamily (911), CCR by glucose was observed (21,217,530,912). Glucose kinase (443,911) and the accumulation of glycolytic intermediates (694) are implicated in mediating the effect.…”

Carbon source regulation of antibiotic production

“…126 These may include pathway-specific regulators such as MalR and GylR, repressors of the maltose and glycerol operons, respectively, or pleiotropic regulators such as BldB. 131,132 To verify such relationship, MalR, GylR and BldB proteins were heterologously overproduced, purified and assayed for interaction with GlkA. This was approached using several means, including surface plasmon resonance, pull-down assays, a peptide library server, immunoprecipitation and in vivo using two-hybrid technology.…”

Microbial degradation and physico-chemical alteration of polyhydroxyalkanoates by a thermophilic Streptomyces sp.

“…The different effect possessed by glucose and its disaccharide maltose has been reported in gene regulation of maltose utilization pathway in S. coelicolor (van Wezel et al 1997). This suggested that only glucose is the key repressor on PHB depolymerase activity in Streptomyces sp.…”