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Structure of the Phosphatase Domain of the Cell Fate Determinant SpoIIE from Bacillus subtilis

DOI: 10.1016/j.jmb.2011.11.017 DOI Help

Authors: Vladimir Levdikov (University of York) , Elena Blagova (University of York) , Andrea Rawlings (University of York) , Katie Jameson (University of York) , James Tunaley (University of York) , Darren J. Hart (European Molecular Biology Laboratory Grenoble) , Imrich Barak (Institute of Molecular Biology, Slovak Academy of Sciences) , Anthony Wilkinson (University of York)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Molecular Biology , VOL 415 (2)

State: Published (Approved)
Published: November 2011

Open Access Open Access

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 ?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 ?-sheets are packed against one another and flanked by ?-helices in an ???? 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.

Journal Keywords: Spoiie; Phosphatase; Crystal Structure; Sporulation; Manganese Binding

Subject Areas: Biology and Bio-materials

Instruments: I02-Macromolecular Crystallography