Overexpression, crystallization and preliminary X-ray crystallographic analysis of dihydrofolate reductase from bacteriophage T4

Dihydrofolate reductase (DHFR) from bacteriophage T4 is a homodimer consist ing of 193-residue subunits. It has been crystallized in the presence of th e cofactor (NADPH) and an inhibitor (aminopterin) at 296 K using sodium chl oride as precipitant. The crystals are tetragonal, belonging to the space g roup P4(1)22 (or P4(3)22), with unit-cell parameters a = b = 61.14, c = 123 .23 Angstrom under cryogenic conditions. The asymmetric unit contains a sin gle subunit, with a corresponding V-m of 2.65 Angstrom(3) Da(-1) and a solv ent content of 53.6%. Native data have been collected from a crystal to 1.9 Angstrom resolution using synchrotron X-rays.