title: Crystal structure of the Bacillus stearothermophilus anti-sigma factor SpoIIAB with the sporulation sigma factor sigmaF.
abstract: Cell type-specific transcription during Bacillus sporulation is established by sigmaF. SpoIIAB is an anti-sigma that binds and negatively regulates sigmaF, as well as a serine kinase that phosphorylates and inactivates the anti-anti-sigma SpoIIAA. The crystal structure of sigmaF bound to the SpoIIAB dimer in the low-affinity, ADP form has been determined at 2.9 A resolution. SpoIIAB adopts the GHKL superfamily fold of ATPases and histidine kinases. A domain of sigmaF contacts both SpoIIAB monomers, while 80% of the sigma factor is disordered. The interaction occludes an RNA polymerase binding surface of sigmaF, explaining the SpoIIAB anti-sigma activity. The structure also explains the specificity of SpoIIAB for its target sigma factors and, in combination with genetic and biochemical data, provides insight into the mechanism of SpoIIAA anti-anti-sigma activity.
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: Shoko
authors.initials: S
authors.lastname: Masuda
authors.forename: Jing L
authors.initials: JL
authors.lastname: Sun
authors.forename: Oriana
authors.initials: O
authors.lastname: Muzzin
authors.forename: C Anders
authors.initials: CA
authors.lastname: Olson
authors.forename: Sheng
authors.initials: S
authors.lastname: Wang
authors.forename: Seth A
authors.initials: SA
authors.lastname: Darst
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D001665:Binding Sites; D020134:Catalytic Domain; D003461:Crystallography; D019281:Dimerization; D001411:Geobacillus stearothermophilus / Q000737:chemistry*; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D012808:Sigma Factor / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism*; D013171:Spores, Bacterial / Q000737:chemistry; D014157:Transcription Factors
chemical_list: D001426:Bacterial Proteins; D012808:Sigma Factor; D014157:Transcription Factors; C092468:spoIIR protein, Bacillus subtilis; C030069:spore-specific proteins, Bacillus; D000255:Adenosine Triphosphate