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Specific defects in double‐stranded DNA unwinding and homologous pairing of a mutant RecA protein
Author(s) -
Kurumizaka Hitoshi,
Aihara Hideki,
Ikawa Shukuko,
Shibata Takehiko
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01781-6
Subject(s) - homologous chromosome , dna , homologous recombination , pairing , mutant , homology (biology) , biology , microbiology and biotechnology , chemistry , genetics , gene , physics , superconductivity , quantum mechanics
The DNA molecules bound to RecA filaments are extended 1.5‐fold relative to B‐form DNA. This extended DNA structure may be important in the recognition of homology between single‐stranded DNA (ssDNA) and double‐stranded DNA (dsDNA). In this study, we show that the K286N mutation specifically impaired the dsDNA unwinding and homologous pairing activities of RecA, without an apparent effect on dsDNA binding itself. In contrast, the R243Q mutation caused defective dsDNA unwinding, due to the defective dsDNA binding of the C‐terminal domain of RecA. These results provide new evidence that dsDNA unwinding is essential to homology recognition between ssDNA and dsDNA during homologous pairing.