Rapid exchange of A:T base pairs is essential for recognition of DNA homology by human Rad51 recombination protein.
Human Rad51 belongs to a ubiquitous family of proteins that enable a single strand to recognize homology in duplex DNA, and thereby to initiate genetic exchanges and DNA repair, but the mechanism of recognition remains unknown. Kinetic analysis by fluorescence resonance energy transfer combined with the study of base substitutions and base mismatches reveals that recognition of homology, helix destabilization, exchange of base pairs, and initiation of strand exchange are integral parts of a rapid, concerted mechanism in which A:T base pairs play a critical role. Exchange of base pairs is essential for recognition of homology, and physical evidence indicates that such an exchange occurs early enough to mediate recognition.
Gupta
R C
RC
Department of Genetics, Yale University, New Haven, Connecticut 06510, USA.
Folta-Stogniew
E
E
O'Malley
S
S
Takahashi
M
M
Radding
C M
CM
D000225:Adenine / Q000378:metabolism*; D020137:Base Pair Mismatch / Q000235:genetics; D020029:Base Pairing / Q000235:genetics*; D001483:Base Sequence; D003434:Crossing Over, Genetic / Q000235:genetics*; D003596:Cytosine / Q000378:metabolism; D004247:DNA / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004260:DNA Repair / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005453:Fluorescence; D006147:Guanine / Q000378:metabolism; D006801:Humans; D007288:Inosine / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D009154:Mutation / Q000235:genetics; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D051135:Rad51 Recombinase; D012689:Sequence Homology, Nucleic Acid; D013941:Thymine / Q000378:metabolism*
D004268:DNA-Binding Proteins; D009838:Oligodeoxyribonucleotides; D007288:Inosine; D006147:Guanine; D003596:Cytosine; D004247:DNA; C495153:RAD51 protein, human; D051135:Rad51 Recombinase; D000225:Adenine; D013941:Thymine