title: Interaction of G-quadruplex with RecA protein studied in bulk phase and at the single-molecule level.
abstract: As in the human genome there are numerous repeat DNA sequences to adopt into non-B DNA structures such as hairpin, triplex, Z-DNA, G-quadruplex, and so on, an understanding of the interaction between DNA repair proteins and a non-B DNA forming sequence is very important. In this regard, the interaction between RecA protein and human telomeric 5'-TAGGG-(TTAGGG)3-TT-3' sequence and the G-quadruplex formed from this sequence has been investigated in bulk phase and at the single-molecule level. The RecA@ssDNA filament, which is formed by the interaction between RecA protein and a G-rich sequence, was dissociated by the addition of K(+) ions, and the dissociated G-rich sequence was quickly folded to a G-quadruplex structure, indicating that the G-quadruplex structure is more favorable than the RecA@ssDNA filament in the presence of K(+) ions. In addition, we demonstrate that the conformation of the G-quadruplex, which is heterogeneous in the absence of RecA, converged to the specific G-quadruplex with one double-chain-reversal loop upon association of RecA protein.
authors.affiliation: The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tanaka
authors.forename: Jungkweon
authors.initials: J
authors.lastname: Choi
authors.forename: Seog K
authors.initials: SK
authors.lastname: Kim
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Majima
mesh_terms: D002232:Carbocyanines / Q000737:chemistry; D002942:Circular Dichroism; D031541:Fluorescence Resonance Energy Transfer; D054856:G-Quadruplexes; D007477:Ions / Q000737:chemistry; D011188:Potassium / Q000737:chemistry; D011485:Protein Binding; D011938:Rec A Recombinases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D002232:Carbocyanines; D007477:Ions; D011938:Rec A Recombinases; D011188:Potassium