Crystallization and preliminary X-ray crystallographic analysis of NAD(+)-dependent DNA ligase from Thermus filiformis

A highly thermostable DNA ligase from Thermus filiformis has been crystalli zed at room temperature using methoxypolyethylene glycol 5000 as a precipit ant. The crystal belongs to the monoclinic space group P2(1), with unit-cel l parameters a = 90.63, b = 117.80, c = 98.65 Angstrom, beta = 115.56 degre es. Two molecules of DNA ligase are present in the asymmetric unit, giving a crystal volume per protein mass (V-m) of 3.1 Angstrom(3) Da(-1) and a sol vent content of 61%. A native data set extending to 3.0 Angstrom resolution has been collected at 100 K using synchrotron X-rays.