Fig. 9.
The AauSR TCS in the utilization of L-glutamate and L-glutamine in P. aeruginosa PAO1. Extracellular L-glutamate is sensed by the histidine kinase AauS, which subsequently phosphorylates its cognate partner EBP AauR. Phosphorylated AauR (shown as a hexamer [6]) interacts with the RpoN-RNA polymerase complex and mediates the transcriptional activation of the aatJ-aatQMP genes from the − 12/− 24 promoter (PRpoN). The ansB and ggt genes are potentially transcribed with aatJ-aatQMP, but experimental verification is needed. The periplasmic glutaminase-asparaginase AnsB catalyzes the deamidation of L-glutamine to yield L-glutamate whereas the metabolic role of Ggt is unknown but might involve the liberation of L-glutamate from the hydrolysis of γ-glutamyl compounds such as glutathione