title: A conserved structural module regulates transcriptional responses to diverse stress signals in bacteria.
abstract: A transcriptional response to singlet oxygen in Rhodobacter sphaeroides is controlled by the group IV sigma factor sigma(E) and its cognate anti-sigma ChrR. Crystal structures of the sigma(E)/ChrR complex reveal a modular, two-domain architecture for ChrR. The ChrR N-terminal anti-sigma domain (ASD) binds a Zn(2+) ion, contacts sigma(E), and is sufficient to inhibit sigma(E)-dependent transcription. The ChrR C-terminal domain adopts a cupin fold, can coordinate an additional Zn(2+), and is required for the transcriptional response to singlet oxygen. Structure-based sequence analyses predict that the ASD defines a common structural fold among predicted group IV anti-sigmas. These ASDs are fused to diverse C-terminal domains that are likely involved in responding to specific environmental signals that control the activity of their cognate sigma factor.
authors.affiliation: The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Campbell
authors.forename: Roger
authors.initials: R
authors.lastname: Greenwell
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: Anthony
authors.forename: Sheng
authors.initials: S
authors.lastname: Wang
authors.forename: Lionel
authors.initials: L
authors.lastname: Lim
authors.forename: Kalyan
authors.initials: K
authors.lastname: Das
authors.forename: Heidi J
authors.initials: HJ
authors.lastname: Sofia
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Donohue
authors.forename: Seth A
authors.initials: SA
authors.lastname: Darst
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology; D001665:Binding Sites; D018360:Crystallography, X-Ray; D015964:Gene Expression Regulation, Bacterial; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010100:Oxygen / Q000378:metabolism; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D012242:Rhodobacter sphaeroides / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D012808:Sigma Factor / Q000737:chemistry* / Q000502:physiology; D014157:Transcription Factors / Q000737:chemistry* / Q000502:physiology; D014158:Transcription, Genetic / Q000502:physiology*; D015032:Zinc / Q000378:metabolism