title: Cyclobutylpyrimidine dimer base flipping by DNA photolyase.
abstract: DNA Photolyase is a flavoprotein that uses light to repair cyclobutylpyrimidine dimers in DNA. From considerations of the crystal structure of the protein, it has been hypothesized that the dimer lesion is flipped out of the DNA double helix into the substrate binding pocket. We have used a fluorescent adenine analog, 2-aminopurine (2-Ap), as a probe of local double helical structure upon binding of the substrate to the protein. Our results show that the local structure around the thymidine lesion changes dramatically upon binding to Photolyase. This is consistent with base flipping of the lesion into the protein binding cavity with concomitant destacking of the opposing complementary 2-Ap nucleotide.
authors.affiliation: Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, USA.
authors.forename: Kathleen S
authors.initials: KS
authors.lastname: Christine
authors.forename: Alexander W
authors.initials: AW
authors.lastname: MacFarlane
authors.forename: Kongsheng
authors.initials: K
authors.lastname: Yang
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Stanley
mesh_terms: D020029:Base Pairing; D004260:DNA Repair; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D009841:Oligonucleotides / Q000378:metabolism / Q000528:radiation effects; D011740:Pyrimidine Dimers / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013696:Temperature; D014466:Ultraviolet Rays
chemical_list: D009841:Oligonucleotides; D011740:Pyrimidine Dimers; D005182:Flavin-Adenine Dinucleotide; D004255:Deoxyribodipyrimidine Photo-Lyase