Determination of the dissociation constant, K_d, of complexes of WRN protein with a 20/46 partial DNA duplex.

<p>Decreasing amounts of 5′-³²P labeled 20/46 partial DNA duplex were incubated under binding conditions with 12 fmol of WRN protein per assay mixture and formed protein-DNA complexes were resolved from free DNA by non-denaturing electrophoresis through 4% polyacrylamide gels in 0.5 X Tris-glycine buffer. Upper panel; Phosphor image of gel-resolved protein-DNA complexes and free DNA. Lower panel; Scatchard plots of the quantified results. A K_d value was inferred from the negative reciprocal of the slope of the shown plot.