Biosynthesis and Heterologous Production of Mycosporine-Like Amino Acid Palythines

Abstract

Mycosporine-like amino acids (MAAs) are a family of natural products that are produced by a variety of organisms for protection from ultraviolet damage. In this work, we combined different bioinformatic approaches to assess the distribution of the MAA biosynthesis and identified a putative gene cluster from Nostoc linckia NIES-25 that encodes a short-chain dehydrogenase/ reductase and a nonheme iron(II)-and 2-oxoglutarate-dependent oxygenase (MysH) as potential new biosynthetic enzymes. Heterologous expression of refactored gene clusters in E. coli produced two known biosynthetic intermediates, 4-deoxygadusol and mycosporine-glycine, and three disubstituted MAA analogues, porphyra-334, shinorine, and mycosporine-glycine-alanine. Importantly, the disubstituted MAAs were converted into palythines by MysH. Furthermore, biochemical characterization revealed the substrate preference of recombinant MysD, a D-Ala-D-Ala ligase-like enzyme for the formation of disubstituted MAAs. Our study advances the biosynthetic understanding of an important family of natural UV photoprotectants and opens new opportunities to the development of next-generation sunscreens.

Metabolites Facilitating Adaptation of Desert Cyanobacteria to Extremely Arid Environments

“…In total, the MAAs biosynthesis pathway represents a very adaptive mechanism to produce a diverse set of UV-protecting pigments in different organisms (such as cyanobacteria, corals, and red algae). Recently, an additional enzyme named mysH was identified in Nostoc lincki that is responsible for further shinorine and porphyra-334 conversion to palythines [ 42 ], suggesting high potential for the development of novel sunscreens with required properties.…”

Genome Mining as an Alternative Way for Screening the Marine Organisms for Their Potential to Produce UV-Absorbing Mycosporine-like Amino Acid

“…The application of heterologous expression systems in recombinant biotechnology is performed via the introduction of foreign biosynthetic gene clusters into the host genome of E. coli , yeast, or other suitable organisms [ 82 , 83 ]. Recombinant proteins are synthesised in different organisms, including bacteria, yeast, and other heterologous expression systems [ 50 , 82 , 83 , 84 ]. In E. coli , human genes were successfully expressed and even manipulated via DNA family shuffling methodology (i.e., molecular evolution in vitro) and analysed for the presence of improved catalytic properties in new mutant genes created [ 58 , 78 , 79 ], and evaluated in the screening process ( Figure 3 d).…”

“…MAAs were also heterologously expressed in E. coli using a 5-gene cluster ( mylA–E ) isolated from cyanobacterium Cylindrospermum stagnale and resulted in the synthesis of mycosporine-lysine and the new MAA mycosporine-ornithine [ 50 ]. An MAA gene cluster isolated from Nostoc linckia resulted in the production of MAA precursor 4-deoxygadusol, then four MAAs (i.e., mycosporine-glycine, porphyra-334, shinorine, mycosporine-glycine-alanine, and palythine) [ 84 ].…”

“…Cyanobacterial MAAs were heterologously expressed as a result of five gene cluster ( mylA to mylE) in E. coli, resulting in the production of mycosporine-lysine and mycosporine-ornithine [ 50 ]. Using a bioinformatic approach, the MAA BCG was identified in Nostoc and expressed in E. coli , producing direct MAA precursor 4-deoxygadusol and five MAAs (mycosporine-glycine, porphyra-334, shinorine, mycosporine-glycine-alanine and palythine [ 84 ]). The MAAs BGC from two Actinomycetales species were found to be homologous to cyanobacterial BGC and, when heterologously expressed in the host Streptomyces, new mycosporine-glycine-alanine was produced [ 47 ].…”

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“…Heterologous expression of refactored mycosporine-like amino acid (MAA) biosynthetic gene clusters in E. coli has led to the production of various biosynthetic intermediates and disubstituted MAA analogues, such as porphyra-334 32 . 25 This work has allowed further characterisation of the MAA enzymes, such as the substrate specificity of MysD, a d -Ala- d -Ala ligase-like enzyme. Modules from pikromycin synthase have been recombined into engineered synthases that can produce predicted enantiomeric triketide lactones ( e.g.…”