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 crystallized at room temperature using methoxypolyethylene glycol 5000 as a precipitant. The crystal belongs to the monoclinic space group P2₁, with unit-cell parameters a = 90.63, b = 117.80, c = 98.65 Å, β = 115.56°. Two molecules of DNA ligase are present in the asymmetric unit, giving a crystal volume per protein mass (V(m)) of 3.1 Å₃Da^-1 and a solvent content of 61%. A native data set extending to 3.0 Å resolution has been collected at 100 K using synchrotron X-rays.