title: Recognition and repair of UV lesions in loop structures of duplex DNA by DASH-type cryptochrome.
abstract: DNA photolyases and cryptochromes (cry) form a family of flavoproteins that use light energy in the blue/UV-A region for the repair of UV-induced DNA lesions or for signaling, respectively. Very recently, it was shown that members of the DASH cryptochrome subclade repair specifically cyclobutane pyrimidine dimers (CPDs) in UV-damaged single-stranded DNA. Here, we report the crystal structure of Arabidopsis cryptochrome 3 with an in-situ-repaired CPD substrate in single-stranded DNA. The structure shows a binding mode similar to that of conventional DNA photolyases. Furthermore, CPD lesions in double-stranded DNA are bound and repaired with similar efficiency as in single-stranded DNA if the CPD lesion is present in a loop structure. Together, these data reveal that DASH cryptochromes catalyze light-driven DNA repair like conventional photolyases but lack an efficient flipping mechanism for interaction with CPD lesions within duplex DNA.
authors.affiliation: Department of Biology, Philipps University, Karl-von-Frisch-Strasse 8, D-35032 Marburg, Germany.
authors.forename: Richard
authors.initials: R
authors.lastname: Pokorny
authors.forename: Tobias
authors.initials: T
authors.lastname: Klar
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hennecke
authors.forename: Thomas
authors.initials: T
authors.lastname: Carell
authors.forename: Alfred
authors.initials: A
authors.lastname: Batschauer
authors.forename: Lars-Oliver
authors.initials: LO
authors.lastname: Essen
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D056931:Cryptochromes; D018360:Crystallography, X-Ray; D004249:DNA Damage / Q000502:physiology / Q000528:radiation effects; D004260:DNA Repair / Q000502:physiology* / Q000528:radiation effects; D018744:DNA, Plant / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017433:Protein Structure, Secondary / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D011740:Pyrimidine Dimers / Q000737:chemistry* / Q000378:metabolism; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D029681:Arabidopsis Proteins; D056931:Cryptochromes; D018744:DNA, Plant; D004277:DNA, Single-Stranded; D011740:Pyrimidine Dimers; C515145:Cry3 protein, Arabidopsis; D004255:Deoxyribodipyrimidine Photo-Lyase