Homologous pairing can occur before DNA strand separation in general genetic recombination.
In the presence of ATP and Mg2+, purified Escherichia coli recA protein promotes the formation of joint molecules between closed circular duplex DNA and homologous circular single-stranded DNA carrying a short annealed fragment. The presence of this fragment is essential for pairing between molecules. In similar conditions recA protein is unable to act as a helicase and does not cause strand separation of the fragment from the single-stranded circle. Thus, homologous pairing between DNA molecules can take place without prior unwinding of a free end.
D001426:Bacterial Proteins / Q000378:metabolism*; D010584:Bacteriophage phi X 174 / Q000235:genetics; D004270:DNA, Circular / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D008957:Models, Genetic; D011938:Rec A Recombinases; D011995:Recombination, Genetic
D001426:Bacterial Proteins; D004270:DNA, Circular; D004277:DNA, Single-Stranded; D004279:DNA, Viral; D011938:Rec A Recombinases