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oai:riuma.uma.es:10630/374452026-02-03T10:53:44Zcom_10630_2254col_10630_37953

00925njm 22002777a 4500 dc Daddaoua, Ab author Molina Santiago, Carlos author de la Torre, Jesús author Krell, Tino author Ramos, Juan Luis author 2014-06-11 In the human pathogen Pseudomonas aeruginosa, the GltR regulator is required for glucose transport, whereas GtrS is a sensor kinase that plays a key role in mediating bacteria–host interaction and pathogen dissemination in the host. We show that GtrS and GltR form a two-component system that regulates the expression from the promoters Pedd/gap-1, PoprB and Pglk, which control the expression of genes involved in glucose metabolism and transport. In addition, the GtrS/GltR pair regulates the expression of toxA that encodes exotoxin A, the primary virulence factor. Microcalorimetry-based ligand screening of the recombinant GtrS ligand-binding domain revealed specific binding of 2-ketogluconate (2-KG) (KD = 5 μM) and 6-phosphogluconate (KD = 98 μM). These effectors accelerate GtrS autophosphorylation, with concomitant transphosphorylation of GltR leading to a three-fold increase in transcription. Surprisingly, in vivo a similar increase in expression from the above promoters was observed for the mutant deficient in GltR regardless of the presence of effectors. The GltR operator site was found to contain the consensus sequence 5′-tgGTTTTTc-3′. We propose that 2-KG is a key metabolite in the stringent transcriptional control of genes involved in virulence and glucose metabolism. We show that GltR is a transcriptional repressor that is released from DNA upon phosphorylation. Nucleic Acids Research, 2014, Vol. 42, No. 12 doi: 10.1093/nar/gku49 https://hdl.handle.net/10630/37445 10.1093/nar/gku496 Pseudomonas aeruginosa GtrS and GltR form a two-component system: the central role of 2-ketogluconate in the expression of exotoxin A and glucose catabolic enzymes in Pseudomonas aeruginosa