Identification of ArgP and Lrp as transcriptional regulators of lysP, the gene encoding the specific lysine permease of E. coli

JIMENA RUIZ; HANEBURGER INA; JUNG KIRSTEN

JOURNAL OF BACTERIOLOGY

AMER SOC MICROBIOLOGY

Lugar: Washington DC; Año: 2011 vol. 193 p. 2536 - 2548

0021-9193

Expression of lysP, which encodes the lysine-specific transporter LysP in Escherichia coli, is regulated by the concentration of exogenous available lysine. In this study, the LysR-type transcriptional regulator ArgP was identified as the activator of lysP expression. At lysine concentrations higher than 25 􏰁M, lysP expression was shut off and phenocopied an argP deletion mutant. Purified ArgP-His6 bound to the lysP promoter/control region at a sequence containing a conserved T-N11-A motif. Its affinity increased in the presence of lysine but not in the presence of the other known coeffector, arginine. In vivo data suggest that lysine-loaded ArgP and arginine-loaded ArgP compete at the lysP promoter. We propose that lysine-loaded ArgP prevents lysP tran- scription at the promoter clearance step, as described for the lysine-dependent regulation of argO (R. S. Laishram and J. Gowrishankar, Genes Dev. 21:1258-1272, 2007). The global regulator Lrp also bound to the lysP promoter/control region. An lrp mutant exhibited reduced lysP expression in the absence of external lysine. These results indicate that ArgP is a major regulator of lysP expression but that Lrp modulates lysP tran- scription under lysine-limiting conditions.