title: Structural basis for the sequestration of the anti-σ(70) factor Rsd from σ(70) by the histidine-containing phosphocarrier protein HPr.
abstract: Histidine-containing phosphocarrier protein (HPr) is a general component of the bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) involved in the phosphorylation-coupled transport of numerous sugars called PTS sugars. HPr mainly exists in a dephosphorylated form in the presence of PTS sugars in the medium, while its phosphorylation increases in the absence of PTS sugars. A recent study revealed that the dephosphorylated form of HPr binds and antagonizes the function of the antisigma factor Rsd. This anti-sigma factor sequesters the housekeeping sigma factor σ(70) to facilitate switching of the sigma subunit on RNA polymerase from σ(70) to the stress-responsive sigma factor σ(S) in stationary-phase cells. In this study, the structure of the complex of Rsd and HPr was determined at 2.1 Å resolution and revealed that the binding site for HPr on the surface of Rsd partly overlaps with that for σ(70). The localization of the phosphorylation site on HPr at the binding interface for Rsd explains why phosphorylation of HPr abolishes its binding to Rsd. The mutation of crucial residues involved in the HPr-Rsd interaction significantly influenced the competition between HPr and σ(70) for binding to Rsd both in vitro and in vivo. The results provide a structural basis for the linkage of global gene regulation to nutrient availability in the external environment.
authors.affiliation: Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 151-742, Republic of Korea.
authors.forename: Young Ha
authors.initials: YH
authors.lastname: Park
authors.affiliation: Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul 151-921, Republic of Korea.
authors.forename: Si Hyeon
authors.initials: SH
authors.lastname: Um
authors.affiliation: Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul 151-921, Republic of Korea.
authors.forename: Saemee
authors.initials: S
authors.lastname: Song
authors.affiliation: Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 151-742, Republic of Korea.
authors.forename: Yeong Jae
authors.initials: YJ
authors.lastname: Seok
authors.affiliation: Department of Agricultural Biotechnology, Center for Food Safety and Toxicology, Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul 151-921, Republic of Korea.
authors.forename: Nam Chul
authors.initials: NC
authors.lastname: Ha
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D018360:Crystallography, X-Ray; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry* / Q000378:metabolism; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D012097:Repressor Proteins / Q000737:chemistry* / Q000378:metabolism; D012808:Sigma Factor / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; C112239:Rsd protein, E coli; D012808:Sigma Factor; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C030182:phosphocarrier protein HPr; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases
keywords: HPr; PTS; Rsd; stationary phase; σ70