CRYSTALLIZATION AND PRELIMINARY-X-RAY DIFFRACTION ANALYSIS OF THE ARSC PROTEIN FROM THE ESCHERICHIA-COLI ARSENICAL RESISTANCE PLASMID, R773

Diffraction data to 3.0 Angstrom resolution were collected on crystals of ArsC protein from the conjugative resistance factor R773 which med iates arsenical resistance in the Gram negative bacterium Escherichia coli. The crystal system is tetragonal, a = 116.2 Angstrom, c = 145.0 Angstrom and the space group is either P4(1)2(1)2 or P4(3)2(1)2. The m ost probable range for the contents of the asymmetric unit is four to eight ArsC molecules (M(r) = 15,811).