title: The class III cyclobutane pyrimidine dimer photolyase structure reveals a new antenna chromophore binding site and alternative photoreduction pathways.
abstract: Photolyases are proteins with an FAD chromophore that repair UV-induced pyrimidine dimers on the DNA in a light-dependent manner. The cyclobutane pyrimidine dimer class III photolyases are structurally unknown but closely related to plant cryptochromes, which serve as blue-light photoreceptors. Here we present the crystal structure of a class III photolyase termed photolyase-related protein A (PhrA) of Agrobacterium tumefaciens at 1.67-Å resolution. PhrA contains 5,10-methenyltetrahydrofolate (MTHF) as an antenna chromophore with a unique binding site and mode. Two Trp residues play pivotal roles for stabilizing MTHF by a double π-stacking sandwich. Plant cryptochrome I forms a pocket at the same site that could accommodate MTHF or a similar molecule. The PhrA structure and mutant studies showed that electrons flow during FAD photoreduction proceeds via two Trp triads. The structural studies on PhrA give a clearer picture on the evolutionary transition from photolyase to photoreceptor.
authors.affiliation: From the Charité, University Medicine Berlin, Institute of Medical Physics and Biophysics (CC2), AG Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany, patrick.scheerer@charite.de.
authors.forename: Patrick
authors.initials: P
authors.lastname: Scheerer
authors.affiliation: the Karlsruhe Institute of Technology (KIT), Botanical Institute, Kaiserstr. 2, D-76131 Karlsruhe, Germany.
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
authors.affiliation: From the Charité, University Medicine Berlin, Institute of Medical Physics and Biophysics (CC2), AG Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Kalms
authors.affiliation: the Structural Biology Group, European Synchroton Radiation Facility, CS 40220, F-38043 Grenoble Cedex 9, France, and.
authors.forename: David
authors.initials: D
authors.lastname: von Stetten
authors.affiliation: the Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road, London E1 4NS, United Kingdom.
authors.forename: Norbert
authors.initials: N
authors.lastname: Krauß
authors.affiliation: the Karlsruhe Institute of Technology (KIT), Botanical Institute, Kaiserstr. 2, D-76131 Karlsruhe, Germany, oberpichler@gsl.uni-luebeck.de.
authors.forename: Inga
authors.initials: I
authors.lastname: Oberpichler
authors.affiliation: the Karlsruhe Institute of Technology (KIT), Botanical Institute, Kaiserstr. 2, D-76131 Karlsruhe, Germany, tilman.lamparter@kit.edu.
authors.forename: Tilman
authors.initials: T
authors.lastname: Lamparter
mesh_terms: D016960:Agrobacterium tumefaciens / Q000201:enzymology; D001665:Binding Sites; D018360:Crystallography, X-Ray; D003580:Cytochromes / Q000378:metabolism; D004249:DNA Damage; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000737:chemistry / Q000378:metabolism*; D004795:Enzyme Stability; D019143:Evolution, Molecular; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D010084:Oxidation-Reduction / Q000528:radiation effects; D017434:Protein Structure, Tertiary; D011740:Pyrimidine Dimers / Q000737:chemistry / Q000378:metabolism*; D013763:Tetrahydrofolates / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: D003580:Cytochromes; D011740:Pyrimidine Dimers; D013763:Tetrahydrofolates; D005182:Flavin-Adenine Dinucleotide; C018092:5,10-methenyltetrahydrofolate; D004255:Deoxyribodipyrimidine Photo-Lyase
keywords: Cryptochrome; Crystal Structure; DNA Repair; Flavin Adenine Dinucleotide (FAD); Molecular Evolution; Mutagenesis in Vitro; Photobiology; Photoreceptor; Photoreduction; Site-directed Mutagenesis