Crystallization and preliminary crystallographic studies of Sfp: a phosphopantetheinyl transferase of modular peptide synthetases

The Bacillus subtilis Sfp protein is required for the non-ribosomal biosynthesis of the lipoheptapeptide antibiotic surfactin. It converts seven peptidyl carrier protein (PCP) domains of the surfactin synthetase SfrA-(A-C) to their active hole-forms by 4'-phosphopantetheinylation. The B. subtilis sfp gene was overexpressed in Escherichia coli and its gene product was purified to homogeneity and crystallized. Well diffracting single crystals were obtained from Sfp as well as from a selenomethionyl derivative, using sodium formate as a precipitant. The crystals belong to the tetragonal space group P4(1)2(1)2/P4(3)2(1)2, with unit-cell parameters a = b = 65.3, c = 150.5 Angstrom. They diffract beyond 2.8 Angstrom and contain one molecule in the asymmetric unit.