title: Crystal Structures of Bacterial (6-4) Photolyase Mutants with Impaired DNA Repair Activity.
abstract: PhrB from Agrobacterium fabrum is the first prokaryotic photolyase which repairs (6-4) UV DNA photoproducts. The protein harbors three cofactors: the enzymatically active FAD chromophore, a second chromophore, 6,7-dimethyl-8-ribityllumazine (DMRL) and a cubane-type Fe-S cluster. Tyr424 of PhrB is part of the DNA-binding site and could provide an electron link to the Fe-S cluster. The PhrBY424Fmutant showed reduced binding of lesion DNA and loss of DNA repair. The mutant PhrBI51Wis characterized by the loss of the DMRL chromophore, reduced photoreduction and reduced DNA repair capacity. We have determined the crystal structures of both mutants and found that both mutations only affect local protein environments, whereas the overall fold remained unchanged. The crystal structure of PhrBY424Frevealed a water network extending to His366, which are part of the lesion-binding site. The crystal structure of PhrBI51Wshows how the bulky Trp leads to structural rearrangements in the DMRL chromophore pocket. Spectral characterizations of PhrBI51Wsuggest that DMRL serves as an antenna chromophore for photoreduction and DNA repair in the wild type. The energy transfer from DMRL to FAD could represent a phylogenetically ancient process.
authors.affiliation: Karlsruhe Institute of Technology, Botanical Institute, Karlsruhe, Germany.|Institute of Materials, China Academy of Engineering Physics, Mianyang, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Karlsruhe Institute of Technology, Botanical Institute, Karlsruhe, Germany.
authors.forename: Hongju
authors.initials: H
authors.lastname: Ma
authors.affiliation: Department of Chemistry, University of Illinois at Chicago, Chicago, IL.
authors.forename: Kalinga
authors.initials: K
authors.lastname: Bowatte
authors.affiliation: Charité - Universitätsmedizin Berlin, Institute of Medical Physics and Biophysics (CC2), Group Protein X-ray Crystallography and Signal Transduction, Berlin, Germany.
authors.forename: Dennis
authors.initials: D
authors.lastname: Kwiatkowski
authors.affiliation: Karlsruhe Institute of Technology, Botanical Institute, Karlsruhe, Germany.
authors.forename: Esther
authors.identifier: 0000-0001-5642-1232
authors.initials: E
authors.lastname: Mittmann
authors.affiliation: Karlsruhe Institute of Technology, Botanical Institute, Karlsruhe, Germany.
authors.forename: Heba
authors.initials: H
authors.lastname: Qasem
authors.affiliation: Karlsruhe Institute of Technology, Botanical Institute, Karlsruhe, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Krauß
authors.affiliation: Department of Chemistry, University of Illinois at Chicago, Chicago, IL.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Zeng
authors.affiliation: Department of Chemistry, University of Illinois at Chicago, Chicago, IL.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Ren
authors.affiliation: Charité - Universitätsmedizin Berlin, Institute of Medical Physics and Biophysics (CC2), Group Protein X-ray Crystallography and Signal Transduction, Berlin, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Scheerer
authors.affiliation: Department of Chemistry, University of Illinois at Chicago, Chicago, IL.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Yang
authors.affiliation: Karlsruhe Institute of Technology, Botanical Institute, Karlsruhe, Germany.
authors.forename: Tilman
authors.initials: T
authors.lastname: Lamparter
mesh_terms: D060054:Agrobacterium / Q000201:enzymology; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D018360:Crystallography, X-Ray; D004260:DNA Repair; D004269:DNA, Bacterial / Q000378:metabolism; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D004735:Energy Transfer; D009154:Mutation; D011487:Protein Conformation
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; C098727:pyrimidine(6-4)pyrimidone photolyase; D004255:Deoxyribodipyrimidine Photo-Lyase