title: Optical sequence probing with the homologous recombination protein RecA.
abstract: In this study, we used the homologous recombination protein RecA to locate a specific sequence on DNA. Single-stranded (ss) DNA (80-mer, 5'-biotinylated), complementary to the sequence of interest, was labeled with quantum dots (Qdots(®)) via biotin-avidin binding. The DNA was then mixed with RecA to form a fluorescent-labeled ssDNA-RecA complex. λ DNA, which was used as the target DNA, was stretch-and-positioned onto microelectrodes by using the electrostatic method. When the ssDNA-RecA complex was fed to the suspended target DNA, clear fluorescence spots were observed on individual target DNA molecules. The histogram of the probe-binding position along the target DNA was measured, and the peak was found to correspond to the location complementary to the probe ssDNA. This result shows a potential use for recombination proteins in facilitating the optical detection of DNA sequences.
authors.affiliation: Department of Bioengineering, The University of Tokyo, Tokyo, Japan. yuji.kimura@crl.hpk.co.jp
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kimura
authors.forename: Yuya
authors.initials: Y
authors.lastname: Goto
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Oana
authors.forename: Masao
authors.initials: M
authors.lastname: Washizu
mesh_terms: D004277:DNA, Single-Stranded / Q000737:chemistry / Q000378:metabolism; D005456:Fluorescent Dyes / Q000737:chemistry / Q000378:metabolism; D059765:Homologous Recombination; D057054:Molecular Imaging / Q000379:methods; D061848:Optical Imaging / Q000379:methods*; D045663:Quantum Dots; D011938:Rec A Recombinases / Q000737:chemistry / Q000378:metabolism*; D017422:Sequence Analysis, DNA / Q000379:methods*; D055672:Static Electricity
chemical_list: D004277:DNA, Single-Stranded; D005456:Fluorescent Dyes; D011938:Rec A Recombinases