title: Functional Conversion of CPD and (6-4) Photolyases by Mutation.
abstract: Ultraviolet (UV) light from the sun damages DNA by forming a cyclobutane pyrimidine dimer (CPD) and pyrimidine(6-4)pyrimidone photoproducts [(6-4) PP]. Photolyase (PHR) enzymes utilize near-UV/blue light for DNA repair, which is initiated by light-induced electron transfer from the fully reduced flavin adenine dinucleotide chromophore. Despite similar structures and repair mechanisms, the functions of PHR are highly selective; CPD PHR repairs CPD, but not (6-4) PP, and vice versa. In this study, we attempted functional conversion between CPD and (6-4) PHRs. We found that a triple mutant of (6-4) PHR is able to repair the CPD photoproduct, though the repair efficiency is 1 order of magnitude lower than that of wild-type CPD PHR. Difference Fourier transform infrared spectra for repair demonstrate the lack of secondary structural alteration in the mutant, suggesting that the triple mutant gains substrate binding ability while it does not gain the optimized conformational changes from light-induced electron transfer to the release of the repaired DNA. Interestingly, the (6-4) photoproduct is not repaired by the reverse mutation of CPD PHR, and eight additional mutations (total of 11 mutations) introduced into CPD PHR are not sufficient. The observed asymmetric functional conversion is interpreted in terms of a more complex repair mechanism for (6-4) repair, which was supported by quantum chemical/molecular mechanical calculation. These results suggest that CPD PHR may represent an evolutionary origin for photolyase family proteins.
authors.affiliation: Department of Frontier Materials, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan.
authors.forename: Daichi
authors.initials: D
authors.lastname: Yamada
authors.affiliation: Institute of Molecular and Cellular Biosciences, The University of Tokyo , 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
authors.forename: Hisham M
authors.initials: HM
authors.lastname: Dokainish
authors.affiliation: Department of Frontier Materials, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan.|OptoBioTechnology Research Center, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Iwata
authors.affiliation: Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka 560-8531, Japan.
authors.forename: Junpei
authors.initials: J
authors.lastname: Yamamoto
authors.affiliation: Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University , Osaka 565-0871, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University , Osaka 565-0871, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Todo
authors.affiliation: Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka 560-8531, Japan.
authors.forename: Shigenori
authors.initials: S
authors.lastname: Iwai
authors.affiliation: Department of Integrative Structural and Computational Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute , La Jolla, California 92037, United States.
authors.forename: Elizabeth D
authors.initials: ED
authors.lastname: Getzoff
authors.affiliation: Institute of Molecular and Cellular Biosciences, The University of Tokyo , 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Kitao
authors.affiliation: Department of Frontier Materials, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan.|OptoBioTechnology Research Center, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Kandori
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D020134:Catalytic Domain / Q000235:genetics; D018360:Crystallography, X-Ray; D004249:DNA Damage; D004260:DNA Repair; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D004579:Electron Transport; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D011740:Pyrimidine Dimers / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared; D014466:Ultraviolet Rays; D014982:Xenopus laevis
chemical_list: D011740:Pyrimidine Dimers; D011994:Recombinant Proteins; C098727:pyrimidine(6-4)pyrimidone photolyase; D004255:Deoxyribodipyrimidine Photo-Lyase