Figure 4.

Novel ATP-binding domain of the RECQ4 N terminus. (A) Spin-column analysis of the binding of α³²P-ATP by the indicated protein. Following centrifugation, the α³²P-ATP present in the flow through or void volume indicates the amount bound by the indicated protein. (B) Spin-column analysis of the binding of α³²P-ATP by the indicated amounts of RECQ4^1–492 in the presence (open circle) or absence (close circle) of MgCl₂. (C) Visualization of RECQ4^1–492 fragment binding to α³²P-8-azido-ATP after UV crosslinking by autoradiography following SDS–PAGE. (D) Trypsin proteolysis mapping of RECQ4^1–492 in the presence or absence of ATP. Protein fragments were separated on SDS–PAGE followed by western blot analysis using anti-FLAG antibody. (E) DNA strand annealing activities of the RECQ4 full length (FL) and fragments (5 nM each). DNA annealing of ³²P-labelled S1 and unlabelled complementary S2 oligos were carried out using the indicated proteins without ATP (upper panel) or in the presence of ATP (lower panel).