Towards the Understanding of the Function of Lanthipeptide and TOMM-Related Genes in Haloferax mediterranei .

Research on secondary metabolites produced by Archaea such as ribosomally synthesized and post-translationally modified peptides (RiPPs) is limited. The genome of ATCC 33500 encodes lanthipeptide synthetases (M1, M2, and M3) and a thiazole-forming cyclodehydratase (), possibly involved in the biosynthesis of lanthipeptides and the TOMMs haloazolisins, respectively. Lanthipeptides and TOMMs often have antimicrobial activity, and has antagonistic activity towards haloarchaea shown to be independent of M genes. This study investigated (i) the transcription of and M genes, (ii) the involvement of YcaO in bioactivity, and (iii) the impact of YcaO and MedM-encoding genes' absence in the biomolecular profile of . The assays were performed with biomass grown in agar and included RT-qPCR, the generation of knockout mutants, bioassays, and FTIR analysis. Results suggest that and M genes are transcriptionally active, with the highest number of transcripts observed for M2. The deletion of gene had no effect on antihaloarchaea activity. FTIR analysis of M and knockout mutants suggest that MedMs and YcaO activity might be directly or indirectly related t lipids, a novel perspective that deserves further investigation.