Figure 2.

Strand exchange mediated by HsRad51. Strand exchange reactions were done with single-stranded 83-mer A16(−) and duplex 83-mer 5′-³²P-A16(−)/A16(+) as described in the text. (A) All lanes contained reaction mixtures with the following omissions or substitutions: lane 1, no protein; lane 2, HsRad51 but no ssDNA; lane 3, HsRad51 complete reaction in presence of ATP; lane 4, HsRad51 with X16 substituted for A16(−) as a heterologous control; lane 5, HsRad51 without ATP; lane 6, HsRad51 without Mg²⁺; lane 7, RecA substituted for HsRad51 in a complete reaction; lane 8, HsRad51 with ATP[γS] in place of ATP. (B) Lack of strand exchange mediated by HsRad51 in presence of ATP[γS]. Lanes 1, 2, 3, and 4, complete HsRad51 reaction at 5, 15, 30, and 45 min, respectively; lanes 5, 6, 7, and 8, complete RecA reaction at 5, 10, 15, and 30 min, respectively.