Utilization of L-glutamate as a preferred or sole nutrient in

摘要

Genetic organization of the aatJ-aatQMP genes of P. aeruginosa PAO1. a The uptake of acidic amino acids is believed to mediated through an ABC transporter complex encoded by the aatJ-aatQMP cluster. Positioned 131–144 bp upstream of the aatJ ORF is a putative −12/−24 promoter (PRpoN), which is the promoter specifically recognized by the sigma factor RpoN. Located upstream of the − 12/− 24 promoter are two sequences or motifs resembling the consensus DNA-binding site for the EBP AauR of P. putida KT2440. The presence of these predicted sites is a strong indicator that both AauR and RpoN are involved in the regulation of aatJ-aatQMP genes, and therefore, the transport of acidic amino acids. To investigate this regulation, two β-galactosidase (LacZ) reporters were constructed and are illustrated: aatJ-lacZ and aatQ-lacZ. Although not the subject of the current study, the ansB and ggt genes potentially form an operon with aatJ-aatQMP, and collectively, are coordinately regulated in response to acidic amino acids and their amide derivatives in P. aeruginosa PAO1. b Close-up view of the putative − 12/− 24 promoter (PRpoN) and AauR-binding site (motifs 1 and 2) located upstream of the aatJ ORF in P. aeruginosa PAO1