Control of gene expression is key to development and adaptation. Using purified transcription components from bacteria, we employ structural and functional studies in an integrative manner to elaborate a detailed description of an obligatory step, the accessing of the DNA template, in gene expression. Our work focuses on a specialized molecular machinery that utilizes ATP hydrolysis to initiate DNA opening and permits a description of how the events triggered by ATP hydrolysis within a transcriptional activator can lead to DNA opening and transcription. The bacterial EBPs (enhancer binding proteins) that belong to the AAA+ (ATPases associated with various cellular activities) protein family remodel the RNAP (RNA polymerase) holoenzyme containing the σ54 factor and convert the initial, transcriptionally silent promoter complex into a transcriptionally proficient open complex using transactions that reflect the use of ATP hydrolysis to establish different functional states of the EBP. A molecular switch within the model EBP we study [called PspF (phage shock protein F)] is evident, and functions to control the exposure of a solvent-accessible flexible loop that engages directly with the initial RNAP promoter complex. The σ54 factor then controls the conformational changes in the RNAP required to form the open promoter complex.
A second paradigm for gene activation in bacteria
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M. Buck, D. Bose, P. Burrows, W. Cannon, N. Joly, T. Pape, M. Rappas, J. Schumacher, S. Wigneshweraraj, X. Zhang; A second paradigm for gene activation in bacteria. Biochem Soc Trans 1 December 2006; 34 (6): 1067–1071. doi: https://doi.org/10.1042/BST0341067
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