title: Structure of the phosphatase domain of the cell fate determinant SpoIIE from Bacillus subtilis.
abstract: Sporulation in Bacillus subtilis begins with an asymmetric cell division producing two genetically identical cells with different fates. SpoIIE is a membrane protein that localizes to the polar cell division sites where it causes FtsZ to relocate from mid-cell to form polar Z-rings. Following polar septation, SpoIIE establishes compartment-specific gene expression in the smaller forespore cell by dephosphorylating the anti-sigma factor antagonist SpoIIAA, leading to the release of the RNA polymerase sigma factor σ(F) from an inhibitory complex with the anti-sigma factor SpoIIAB. SpoIIE therefore couples morphological development to differential gene expression. Here, we determined the crystal structure of the phosphatase domain of SpoIIE to 2.6 Å spacing, revealing a domain-swapped dimer. SEC-MALLS (size-exclusion chromatography with multi-angle laser light scattering) analysis however suggested a monomer as the principal form in solution. A model for the monomer was derived from the domain-swapped dimer in which 2 five-stranded β-sheets are packed against one another and flanked by α-helices in an αββα arrangement reminiscent of other PP2C-type phosphatases. A flap region that controls access of substrates to the active site in other PP2C phosphatases is diminished in SpoIIE, and this observation correlates with the presence of a single manganese ion in the active site of SpoIIE in contrast to the two or three metal ions present in other PP2C enzymes. Mapping of a catalogue of mutational data onto the structure shows a clustering of sites whose point mutation interferes with the proper coupling of asymmetric septum formation to sigma factor activation and identifies a surface involved in intramolecular signaling.
authors: Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5YW, UK.
authors: Vladimir M
authors: VM
authors: Levdikov
authors: Elena V
authors: EV
authors: Blagova
authors: Andrea E
authors: AE
authors: Rawlings
authors: Katie
authors: K
authors: Jameson
authors: James
authors: J
authors: Tunaley
authors: Darren J
authors: DJ
authors: Hart
authors: Imrich
authors: I
authors: Barak
authors: Anthony J
authors: AJ
authors: Wilkinson
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000737:chemistry* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D002850:Chromatography, Gel; D018360:Crystallography, X-Ray; D008345:Manganese / Q000378:metabolism; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics; D017354:Point Mutation; D011485:Protein Binding; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D050505:Mutant Proteins; C030069:spore-specific proteins, Bacillus; D008345:Manganese