Crystallization and preliminary X-ray diffraction studies of the N-terminal domain of the phosphorylating subunit of mannose permease from Escherichia coli

Mannose permease is a constitutive component of the phosphotransferase system in Escherichia coli. This complex consists of two transmembrane subunits (II-PMan, Mr = 28,000 and II-MMan, Mr = 31,000) and a hydrophilic subunit (IIIMan). IIIMan functions as a phosphorylating enzyme and exists as a soluble homo-dimer of Mr = 70,000 in the cytosol. The N-terminal domain (P13) of IIIMan contains a phosphorylation site and the interface for dimerization. P13 has been crystallized in two different forms: type I, orthorhombic, space group C222 with a = 98.7 A, b = 106.5 A and c = 57.4 A, and type II, monoclinic, space group P2(1), with a = 54.4 A, b = 100.5 A, c = 58.1 A and beta = 90.5 degrees. Both types of crystal are suitable for X-ray diffraction studies.