title: Crystal structure of SpoVT, the final modulator of gene expression during spore development in Bacillus subtilis.
abstract: Endospore formation in Bacillus subtilis is orchestrated by five developmental sigma factors and further modulated by several auxiliary transcription factors. One of these, SpoVT, regulates forespore-specific sigma(G)-dependent genes and plays a key role in the final stages of spore formation. We have determined the crystal structure of the isolated C-terminal domain of SpoVT at 1.5 A by experimental phasing techniques and used this model to solve the structure of the full-length SpoVT at 2.6 A by molecular replacement. SpoVT is a tetramer that shows an overall significant distortion mediated by electrostatic interactions. Two monomers dimerize via the highly charged N-terminal domains to form swapped-hairpin beta-barrels. These asymmetric dimers further tetramerize through the formation of mixed helix bundles between their C-terminal domains, which themselves fold as GAF (cGMP-specific and cGMP-stimulated phosphodiesterases, Anabaena adenylate cyclases, and Escherichia coli FhlA) domains. The combination of a swapped-hairpin beta-barrel with a GAF domain represents a novel domain architecture in transcription factors. The occurrence of SpoVT homologs throughout Bacilli and Clostridia demonstrates the ancestral origin of this factor in sporulation.
authors.affiliation: Department of Membrane Biochemistry, Max Planck Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
authors.forename: Iris
authors.initials: I
authors.lastname: Asen
authors.forename: Sergej
authors.initials: S
authors.lastname: Djuranovic
authors.forename: Andrei N
authors.initials: AN
authors.lastname: Lupas
authors.forename: Kornelius
authors.initials: K
authors.lastname: Zeth
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics*; D001426:Bacterial Proteins / Q000737:chemistry*; D002850:Chromatography, Gel; D018360:Crystallography, X-Ray; D015964:Gene Expression Regulation, Bacterial; D008958:Models, Molecular; D008969:Molecular Sequence Data; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D013171:Spores, Bacterial / Q000235:genetics*; D014157:Transcription Factors / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D014157:Transcription Factors