title: Interaction surface of the Spo0A response regulator with the Spo0E phosphatase.
abstract: Spo0A~P is the essential response regulator and transcription factor for sporulation initiation in Bacillus subtilis. The phosphorylation level of Spo0A in the cell is determined by the sensor kinase activity of the phosphorelay, donating phosphoryl groups, and the antagonistic effects of dephosphorylation mediated by the Rap and Spo0E families of phosphatases. In this study, spo0A mutations were generated that encoded proteins less sensitive to the activity of Spo0E than the wild-type protein. The Spo0A substitutions N12K, P60S, L62P and F88L are surface exposed and localize to the same face of the molecule as the active site and in its close proximity on the beta1-alpha1, beta3-alpha3 and beta4-alpha4 loops. The corresponding surface in the Spo0F response regulator was shown previously to be involved in the interaction with the RapB phosphatase, as well as the KinA histidine kinase and the Spo0B phosphotransferase. Thus, residues occupying the same position (N12:Q12, F88:Y84) and the same loops in Spo0A or Spo0F are involved in the interaction with the structurally unrelated Spo0E and RapB phosphatases, respectively, in addition to kinases and phosphotransferase. The specificity in phosphatase target recognition must be the result of side-chain variability within the response regulators and the interactions they promote. The residues involved in Spo0E interaction are identical in all Spo0A orthologues from spore-forming Bacilli encoding Spo0E phosphatases.
authors.affiliation: Division of Cellular Biology, Department of Molecular and Experimental Medicine, MEM-116, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
authors.forename: Sophie J
authors.initials: SJ
authors.lastname: Stephenson
authors.forename: Marta
authors.initials: M
authors.lastname: Perego
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D001412:Bacillus subtilis / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid; D012808:Sigma Factor; D015398:Signal Transduction / Q000502:physiology*; D013171:Spores, Bacterial / Q000201:enzymology / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D012808:Sigma Factor; C080950:Spo0A protein, Bacillus subtilis; C080951:Spo0F protein, Bacillus subtilis; D014157:Transcription Factors; C075521:kinA protein, Bacillus subtilis; C092468:spoIIR protein, Bacillus subtilis; C030069:spore-specific proteins, Bacillus; D011494:Protein Kinases; C091155:rapB protein, Bacillus subtilis; D010749:Phosphoprotein Phosphatases