In silico analysis of enzymes involved in mycosporine-like amino acids biosynthesis in Euhalothece sp.: Structural and functional characterization

Mycosporine-like amino acids (MAAs) are ultraviolet-absorbing compounds synthesized by photoautotrophic microorganisms such as cyanobacteria. They have applications as UV protectants and antioxidants in the cosmetic and pharmaceutical sectors. To date, >30 different types of MAAs have been identified, having an absorption range between 310 and 365 nm that covers most of the UVR spectrum (similar to 295-400 nm). In the study, MAAs were extracted and partially purified from a euryhaline Euhalothece sp. Thereafter, in silico analysis of the MAAs biosynthetic genes was conducted to determine the physicochemical characteristics, structural properties, functional analysis and homology model. High salinity stress (120 g L-1) significantly enhanced the production of MAAs (similar to 56 %) in Euhalothece sp. Bioinformatics analysis of the genome of Euhalothece sp. revealed a distinctive mys gene cluster that contained six genes (mysA to mysE), compared to four genes commonly found in MAA-producing cyanobacteria. Interestingly, both EEVS and DHQ synthase were present, indicating the potential to synthesize MAAs via both the shikimate and sedoheptulose 7-phosphate pathways. Secondary structure analysis confirmed that in all the biosynthetic enzymes, the major components were the alpha-helices with random coils. This study emphasized the unique genes for MAAs in Euhalothece sp. as well as highlighted the potential metabolite pathways for commercial production. Elucidation of the protein structure, physicochemical properties, and interactions provides scientific insight into the biosynthesis of MAAs from hypersaline cyanobacteria. Additionally, it is essential for determining the applications of these novel photoprotective compounds.