title: DNA photolyases and SP lyase: structure and mechanism of light-dependent and independent DNA lyases.
abstract: Light is essential for many critical biological processes including vision, circadian rhythms, photosynthesis and DNA repair. DNA photolyases use light energy and a fully reduced flavin cofactor to repair the major UV-induced DNA damages, the cis-syn cyclobutane pyrimidine dimers (CPDs) and the pyrimidine-pyrimidone (6-4) photoproducts. Catalysis involves two photoreactions, the photoactivation which leads to the conversion of the flavin cofactor to its catalytic active form and the photorepair whose efficiency depends on a light-harvesting antenna chromophore. Very interestingly, an alternative and light-independent direct reversal mechanism to repair a distinct photolesion is found in bacterial spores, catalyzed by spore photoproduct lyase. This radical SAM enzyme uses an iron-sulfur cluster and S-adenosyl-l-methionine (SAM) to split a specific photoproduct, the so-called spore photoproduct (SP), back to two thymidine residues. The recently solved crystal structure of SP lyase provides new insights into this unique DNA repair mechanism and allows a detailed comparison with DNA photolyases. Similarities as well as divergences between DNA photolyases and SP lyase are highlighted in this review.
authors.affiliation: Department of Biomolecular Mechanisms, Max-Planck Institute for Medical Research, Jahnstrasse 29, Heidelberg, Germany. Alhosna.Benjdia@mpimf-heidelberg.mpg.de
authors.forename: Alhosna
authors.initials: A
authors.lastname: Benjdia
mesh_terms: D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004255:Deoxyribodipyrimidine Photo-Lyase / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D008027:Light; D055668:Photochemical Processes; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*; D012436:S-Adenosylmethionine / Q000737:chemistry / Q000378:metabolism
chemical_list: D011506:Proteins; D012436:S-Adenosylmethionine; D004247:DNA; C088014:spore photoproduct lyase; D004255:Deoxyribodipyrimidine Photo-Lyase