Crystallization and preliminary X-ray crystallographic analysis of the TM1442 gene product from Thermotoga maritima, a homologue of Bacillus subtilisanti-anti-sigma factors

A 110-residue protein encoded by the TM1442 gene of Thermotoga maritima sho ws amino-acid sequence similarity to Bacillus subtilis anti-anti-sigma fact ors RsbV and SpoIIAA. It has been overexpressed in Escherichia coli and the recombinant protein exists primarily as both a monomer and a dimer in solu tion. The dimeric form has been crystallized using polyethylene glycol (PEG ) 8000 as a precipitant. Native X-ray diffraction data have been collected at 100 K to 2.0 Angstrom resolution. The crystals are monoclinic, belonging to the space group P2(1), with unit-cell parameters a = 31.54 (13), b = 11 6.83 (37), c = 31.39 (7) Angstrom, alpha = 90, beta = 119.84 (9), gamma = 9 0 degrees. The asymmetric unit contains two monomers of the recombinant pol ypeptide, with a corresponding V-M of 2.24 Angstrom (3) Da(-1) and a solven t content of 45.0%.