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Georgellis, D; Liu, XQ; Sandoval, GRP; Wanner, BL; Jung, WS; Kwon, O (2009)

EVIDENCE AGAINST THE PHYSIOLOGICAL ROLE OF ACETYL PHOSPHATE IN THE PHOSPHORYLATION OF THE ARCA RESPONSE REGULATOR IN ESCHERICHIA COLI

J MICROBIOL 47(5):657-662
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The Arc two-component signal transduction system of Escherichia coli comprises the ArcB sensor kinase and the ArcA response regulator. Under anoxic growth conditions, ArcB autophosphorylates and transphos-phorylates ArcA, which, in turn, represses or activates its target operons. ArcA has been shown to be able to autophosphorylate in vitro at the expense of acetyl-P. Here, the in vivo effect of acetyl phosphate on the redox signal transduction by the Arc system was assessed. Our results indicate that acetyl phosphate can modulate the expression of ArcA-P target genes only in the absence of ArcB. Therefore, the acetyl phosphate dependent ArcA phosphorylation route does not seem to play a significant role under physiological conditions.