1h4x
From Proteopedia
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STRUCTURE OF THE BACILLUS CELL FATE DETERMINANT SPOIIAA IN THE PHOSPHORYLATED FORM
Overview
BACKGROUND: The asymmetric cell division during sporulation in Bacillus, subtilis gives rise to two compartments: the mother cell and the, forespore. Each follow different programs of gene expression coordinated, by a succession of alternate RNA polymerase sigma factors. The activity of, the first of these sigma factors, sigmaF, is restricted to the forespore, although sigmaF is present in the predivisional cell and partitions into, both compartments following the asymmetric septation. For sigmaF to become, active, it must escape from a complex with its cognate anti-sigma factor, SpoIIAB. This relief from SpoIIAB inhibition requires the, dephosphorylation of the anti-sigma factor antagonist, SpoIIAA. The, phosphorylation state of SpoIIAA is thus a key determinant of sigmaF, activity and cell fate. RESULTS: We have solved the crystal structures of, SpoIIAA from Bacillus sphaericus in its phosphorylated and, unphosphorylated forms. The overall structure consists of a central, beta-pleated sheet, one face of which is buried by a pair of alpha, helices, while the other is largely exposed to solvent. The site of, phosphorylation, Ser57, is located at the N terminus of helix alpha2. The, phosphoserine is exceptionally well defined in the 1.2 A electron density, maps, revealing that the structural changes accompanying phosphorylation, are slight. CONCLUSIONS: Comparison of unphosphorylated and phosphorylated, SpoIIAA shows that covalent modification has no significant effect on the, global structure of the protein. The phosphoryl group has a passive role, as a negatively charged flag rather than the active role it plays as a, nucleus of structural reorganization in many eukaryotic signaling systems.
About this Structure
1H4X is a Single protein structure of sequence from Lysinibacillus sphaericus with TRS as ligand. Structure known Active Sites: AC1 and AC2. Full crystallographic information is available from OCA.
Reference
Structure of the Bacillus cell fate determinant SpoIIAA in phosphorylated and unphosphorylated forms., Seavers PR, Lewis RJ, Brannigan JA, Verschueren KH, Murshudov GN, Wilkinson AJ, Structure. 2001 Jul 3;9(7):605-14. PMID:11470435
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