FIG. 2.

ATP binding activity of the wild type and some mutant helicase proteins. One microgram of the wild-type or mutant helicase proteins was incubated with [α-³²P]ATP in the presence of poly(U) and was UV cross-linked [WT(-UV)] as described in Materials and Methods. Samples were separated by SDS–12.5% PAGE. Following electrophoresis, the gels were stained with Coomassie brilliant blue, dried, and processed for autoradiography. WT, wild-type helicase protein; BSA, bovine serum albumin.