LAUSR

Light is crucial for most of the organisms to perform many biological activities including vision, resetting of circadian rhythm, photosynthesis, and DNA repair. The Cryptochrome/Photolyase Family (CPF) represents an ancient group of UV-A/blue-light sensitive proteins performing different functions such as DNA repair, circadian photoreception, and transcriptional regulation. The CPF is widely distributed throughout all organisms including marine (aquatic) prokaryotes. Bacterium Vibrio cholerae was previously shown to have a CPD photolyase repairing UV-induced thymine dimers; and two CRY-DASHs that repair UV-induced single-stranded DNA damages. Here we characterized a hypothetical gene Vca0809 encoding a new member of photolyase family in this organism. The spectroscopic analysis of the purified protein indicated that this enzyme possessed catalytic cofactor, FAD, and photoantenna chromophore 6,7-dimethyl 8-ribityl-lumazin. With a slot blot-based DNA repair assay, we showed that it possessed (6-4) photolyase activity. Further phylogenetic and computational analyses enabled us to classify this gene as a member of iron-sulfur bacterial cryptochromes and photolyases (FeS-BCP). Therefore, we named this gene as Vc(6-4) FeS-BCP.