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Transcriptional activator proteins that act upon the sigma54-containing form of the bacterial RNA polymerase belong to the extensive AAA+ superfamily of ATPases, members of which are found in all three kingdoms of life and function in diverse cellular processes, often via chaperone-like activities. Formation and collapse of the transition state of ATP for(More)
Escherichia coli can survive extreme acid stress for several hours. The most efficient acid resistance system is based on glutamate decarboxylation by the GadA and GadB decarboxylases and the import of glutamate via the GadC membrane protein. The expression of the corresponding genes is controlled by GadE, the central activator of glutamate-dependent acid(More)
Activators of bacterial sigma54-RNA polymerase holoenzyme are mechanochemical proteins that use adenosine triphosphate (ATP) hydrolysis to activate transcription. We have determined by cryogenic electron microscopy (cryo-EM) a 20 angstrom resolution structure of an activator, phage shock protein F [PspF(1-275)], which is bound to an ATP transition state(More)
A major step in the biogenesis of newly synthesized precursor proteins in bacteria is their targeting to the Sec translocon at the inner membrane. In gram-negative bacteria, the chaperone SecB binds nonnative forms of precursors and specifically transfers them to the SecA motor component of the translocase, thus facilitating their export. The major human(More)
The Escherichia coli phage shock protein system (pspABCDE operon and pspG gene) is induced by numerous stresses related to the membrane integrity state. Transcription of the psp genes requires the RNA polymerase containing the sigma(54) subunit and the AAA transcriptional activator PspF. PspF belongs to an atypical class of sigma(54) AAA activators in that(More)
Members of the protein family called ATPases associated with various cellular activities (AAA(+)) play a crucial role in transforming chemical energy into biological events. AAA(+) proteins are complex molecular machines and typically form ring-shaped oligomeric complexes that are crucial for ATPase activity and mechanism of action. The Escherichia coli(More)
Transcription of the gene osmE of Escherichia coli is inducible by elevated osmotic pressure and during the decelerating phase of growth. osmE expression is directed by a single promoter, osmEp. Decelerating phase induction of osmEp is dependent on the sigmas (RpoS) factor, whereas its osmotic induction is independent of sigmas. Purified Esigmas and(More)
Transcription activation by bacterial sigma(54)-dependent enhancer-binding proteins (EBPs) requires their tri-nucleotide hydrolysis to restructure the sigma(54) RNA polymerase (RNAP). EBPs share sequence similarity with guanine nucleotide binding-proteins and ATPases associated with various cellular activities (AAA) proteins, especially in the(More)