title: Dynamics and stoichiometry of a regulated enhancer-binding protein in live Escherichia coli cells.
abstract: Bacterial enhancer-dependent transcription systems support major adaptive responses and offer a singular paradigm in gene control analogous to complex eukaryotic systems. Here we report new mechanistic insights into the control of one-membrane stress-responsive bacterial enhancer-dependent system. Using millisecond single-molecule fluorescence microscopy of live cells we determine the localizations, two-dimensional diffusion dynamics and stoichiometries of complexes of the bacterial enhancer-binding ATPase PspF during its action at promoters as regulated by inner membrane interacting negative controller PspA. We establish that a stable repressive PspF-PspA complex is located in the nucleoid, transiently communicating with the inner membrane via PspA. The PspF as a hexamer stably binds only one of the two psp promoters at a time, suggesting that psp promoters will fire asynchronously and cooperative interactions of PspF with the basal transcription complex influence dynamics of the PspF hexamer-DNA complex and regulation of the psp promoters.
authors.affiliation: Department of Life Sciences, Imperial College London, London SW7 2AZ, UK.
authors.forename: Parul
authors.initials: P
authors.lastname: Mehta
authors.forename: Goran
authors.initials: G
authors.lastname: Jovanovic
authors.forename: Tchern
authors.initials: T
authors.lastname: Lenn
authors.forename: Andreas
authors.initials: A
authors.lastname: Bruckbauer
authors.forename: Christoph
authors.initials: C
authors.lastname: Engl
authors.forename: Liming
authors.initials: L
authors.lastname: Ying
authors.forename: Martin
authors.initials: M
authors.lastname: Buck
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D004926:Escherichia coli / Q000166:cytology* / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000378:metabolism; D050296:Microbial Viability; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D051877:RNA Polymerase Sigma 54 / Q000378:metabolism; D013312:Stress, Physiological; D015534:Trans-Activators / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; C098954:PspF protein, E coli; D015534:Trans-Activators; C069816:phage shock protein, Bacteria; D051877:RNA Polymerase Sigma 54