Structure, function and interaction studies of the cell differentiation protein SpoIIE from bacillus subtilis. (360G-Wellcome-082829_Z_07_Z)

SpoIIE plays a key morphogenetic role in spore formation by Bacillus subtilis. In this work we propose to determine the three dimensional structure of fragments of SpoIIE which constitute its functional domains. The purpose is to define SpoIIE s interactions with (i) FtsZ which helps to define the asymmetric cell division septum that forms during sporulation and (ii) the anti-sigma factor antagonist, SpoIIAA~P whose dephosphorylation and activation by SpoIIE leads to the establishment of differe ntial gene expression in the sister cells following septation. We have crystals of the phosphatase domain of SpoIIE that are suitable for structure solution and we have strategies for probing the interactions of this domain with SpoIIAA by biophysical, NMR and/or crystallographic techniques. We plan to use a recently devised exhaustive truncation mutagenesis screen for stable and soluble SpoIIE fragments encompassing the FtsZ-binding domain. These fragments will be overproduced and purified for detailed biochemical and biophysical characterisation and structural studies with the ultimate aim of defining the interactions of SpoIIE with FtsZ.