PMC:1140370 / 17434-18423 JSONTXT

Annnotations TAB JSON ListView MergeView

In order to examine more precisely the interaction and helicase actions with forked substrates, Y-fork substrates containing a nascent leading strand (A-fork[3]), nascent lagging strand (A-fork[5]), or both of them (A-fork[3,5]), as well as 5-extension or 3-extension structures were constructed. Mcm4/6/7 bound to A-fork[3] or A-fork[5] with affinity similar to that of a simple Y-fork (Figure 4A and data not shown). In contrast, PriA helicase, used as a control, bound to A-fork[3] more efficiently than to A-fork[5], as reported previously (23,25). Mcm4/6/7 bound also to 5-extension and 3-extension, albeit with slightly reduced affinity compared to A-fork[3] and A-fork[5] (Figure 4A). Mcm4/6/7 bound to A-fork[3,5] with much lower affinity, and the complex gave rise to a single band. These findings indicate that the Mcm4/6/7 complex is loaded onto DNA preferentially and efficiently through single-stranded region, regardless of the presence of 3- or 5-terminus.