The results of FPLC and ATPase analysis. A) FPLC analysis of the mutations by gel filtration chromatography on a Superose-6 column. Molecular marker positions, Ferritin (440 kD) and aldolase (158 kD), are indicated by arrows. B) SDS-PAGE gel analysis of the purified mutant proteins. C) ATPase activity curves for WT, M3 and M8 in the presence and absence of Y-shaped DNA. Error bars representing standard error of the mean are present, but in most cases are too small to see. D) Summary of ATPase data in the presence (black bar) and absence (white bar) of Y-shaped DNA. Error bars are standard error from curve fitting.