Oceanic evolution of the enzyme repairing the UV-induced DNA lesions

Abstract

Solar ultraviolet has a greater impact on marine ecosystem. Bacteria and viruses on ocean surface waters are most exposed to UV radiation on the Earth. In this work, the distribution of the denV gene in samples of marine microbiota was investigated by metagenomic and bioinformatic methods. The bifunctional enzyme encoded by this gene performs excision repair of pyrimidine dimers, the main photoproduct of UVB radiation. 23 homologues of the amino acid sequence of Escherichia virus T4 endonuclease V were found in the Global Ocean Sampling (GOS) database, a metagenome of the microbiota of ocean surface water. Phylogenetic study of these sequences showed that most of them are similar to homologues from cyanobacteria. 3 GOS homologues were found to be more similar to the protein of the marine bacteria Alteromonas sp. Based on the performed phylogenetic analysis it was suggested a horizontal transfer of the denV gene between the Tequatrovirus phages, Enterobacteria, and Bacillus sp. Further research in this direction may shed light on the origin of the DenV protein and its ecological role in marine bacteria and viruses communities.