FIG. 4.

ATPase activity of purified MalK variants. Assays were performed as described previously (10). Rates of hydrolysis are compared to those recorded with wild-type (WT) proteins that were prepared by the same protocol. WT proteins were purified from the soluble fraction of strain BL21(DE3)(pLysS, pES67) (16) (a), from the insoluble fraction of the same strain by a denaturation-renaturation protocol (19) (b), and from the soluble fraction of strain BL21(DE3)(pGS91-1, pOFX-T7-SL1) by nickel-nitrilotriacetic acid-agarose chromatography (c). The data are the averages of at least two independent assays.