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Georgellis, D; Kwon, O; Lynch, AS; Boyd, D; Lin, ECC (2000)

THE ARCB SENSOR KINASE OF ESCHERICHIA COLI: GENETIC EXPLORATION OF THE TRANSMEMBRANE REGION

J BACTERIOL 182(10):2960-2966
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The Arc two-component signal transduction system of Escherichia coli regulates the expression of numerous operons in response to respiratory growth conditions. Cellular redox state or proton motive force (Delta<(mu)over bar>(H+)) has been proposed to be the signal for the membrane-associated ArcB sensor kinase. This study provided evidence for a short ArcB periplasmic bridge that contains a His47. The dispensability of this amino acid, the only amino acid with a pK in the physiological range, renders the Delta<(mu)over bar>(H+) model unlikely. Furthermore, results from substituting membrane segments of ArcB with counterparts of MalF indicate that the region does not play a stereospecific role in signal reception.