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. 2004 Jan 12;32(1):316–327. doi: 10.1093/nar/gkh170

Figure 4.

Figure 4

Figure 4

Strand separation activity of YB-1 on duplex structures containing mismatches or cisplatin cross-links. (AC) The indicated amounts (in ng) of purified human YB-1 proteins were incubated with the indicated radioactive DNA substrates under standard conditions for helicase activity (see Materials and Methods) for 30 min at 37°C. Forty nanograms of GST were used as a negative control. The panels in (A) represent strand separation reactions performed with a 36 bp duplex. The panel on the right contains a reaction performed with a 36mer duplex treated with cisplatin. In (B), reactions were performed with a 36mer duplex containing one base mismatch. In (C), reactions were performed with a 22mer duplex structure containing two nucleotide mismatches. (D) Histogram representation of the YB-1 strand separation reactions performed in (A). The strand displacement data were obtained from experiments done in duplicate with 40 ng of the indicated purified proteins. The percentage strand displacement is calculated by using the formula: c.p.m. of displaced strand/(c.p.m. of displaced strand + c.p.m. of double-stranded DNA) × 100. The c.p.m. was calculated for each band of the gel as indicated in Materials and Methods.