The N-terminal domain of HsRad52 promotes strand exchange. WT HsRad52 and truncated derivatives: Rad52 (1-237), Rad52 (1–184), Rad52 (234–418), or Rad52 (260–340), all at 0.4 μM, were incubated with 6 μM oligonucleotide G16(-), followed by addition of duplex oligonucleotide as described in Materials and Methods.