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ATP ground- and transition states of bac ... h their target protein, sigma54
ATP ground- and transition states of bacterial enhancer binding AAA ATPases support complex formation with their target protein, sigma54
7335
Transcription initiation by the sigma54 form of bacterial RNA polymerase requires hydrolysis of ATP by an enhancer binding protein (EBP). We present SAS-based solution structures of the ATPase domain of the EBP NtrC1 from Aquifex aeolicus in different nucleotide states. Structures of apo protein and that bound to AMPPNP or ADP-BeF(x) (ground-state mimics), ADP-AlF(x) (a transition-state mimic), or ADP (product) show substantial changes in the position of the GAFTGA loops that contact polymerase, particularly upon conversion from the apo state to the ADP-BeF(x) state, and from the ADP-AlF(x) state to the ADP state. Binding of the ATP analogs stabilizes the oligomeric form of the ATPase and its binding to sigma54, with ADP-AlF(x) having the largest effect. These data indicate that ATP binding promotes a conformational change that stabilizes complexes between EBPs and sigma54, while subsequent hydrolysis and phosphate release drive the conformational change needed to open the polymerase/promoter complex.
Chen B, Doucleff M, Wemmer DE, De Carlo S, Huang HH, Nogales E, Hoover TR, Kondrashkina E, Guo L, Nixon BT
Structure (London, England : 1993)
2007-04-01 00:00
15
4
429-40
Integrative Biosciences Graduate Degree Program, Chemical Biology, The Pennsylvania State University, University Park, PA 16802, USA.
Structure
0969-2126
10.1016/j.str.2007.02.007
S0969-2126(07)00106-2
0
False
17437715
