Heterologous expression of a cryptic gene cluster from a marine proteobacterium Thalassomonas actiniarum affords new lanthipeptides thalassomonasins A and B

Abstract

Aims The aim of this study was to utilize a cryptic biosynthetic gene cluster (BGC) of a marine proteobacterium Thalassomonas actiniarum for production of new lanthipeptides by heterologous expression system. Methods and Results Based on genome mining, a new BGC of class I lanthipeptide was found in the genome sequence of a marine proteobacterium T. actiniarum. Molecular cloning was performed to construct an expression vector derived from commercially available plasmid pET‐41a(+). Heterologous production of new lanthipeptides named thalassomonasins A and B was performed using the host Escherichia coli BL21(DE3) harbouring the expression vector. The structure of thalassomonasin A was determined by the interpretation of NMR and MS data. As a result, thalassomonasin A was determined to be a lanthipeptide with three units of lanthionine. The bridging pattern of the lanthionine rings in thalassomonasin A was determined by interpretation of NOESY data. The structure of thalassomonasin B was proposed by MS/MS experiment. Conclusions We succeeded in heterologous production of new class I lanthipeptides using a BGC of a marine proteobacterium T. actiniarum. Significance and Impact of the Study To the best of our knowledge, this is the first report of heterologous production of lanthipeptides derived from proteobacterial origin. There are many cryptic biosynthetic gene clusters (BCGs) of this class of lanthipeptides in proteobacterial genomes. This study may lead to the production of new lanthipeptides by utilizing the BCGs.

Marine Sponge and Octocoral-Associated Bacteria Show Versatile Secondary Metabolite Biosynthesis Potential and Antimicrobial Activities against Human Pathogens

“…RhCl1, notable for their many NRPS and RiPP clusters, are still vastly underexplored and literature reports on the topic are scarce. Nevertheless, one Thalassomonas -derived RiPP cluster was recently characterized and its corresponding lanthipeptides, thalassomonasin A and B, were produced by heterologous expression in Escherichia coli [ 79 ].…”

MGCEP 1.0: A Genetic-Engineered Marine-Derived Chassis Cell for a Scaled Heterologous Expression Platform of Microbial Bioactive Metabolites

“…Likewise, many marine-derived microorganisms are more insubordinate in genetic manipulation, which has caused great obstacles to the characterization of the biosynthesis mechanism of their secondary metabolites. One of the most useful strategies for advancing the research of marine cryptic microbial secondary metabolites is the heterologous expression of BGCs in tractable host organisms. , Through genetic engineering, the selected BGCs could be transferred to different host strains for heterologous expression, which can not only activate the “silent” BGCs and improve the compound yields but also produce unique “unnatural” microbial metabolites. − …”

Unusual Class I Lanthipeptides from the Marine Bacteria Thalassomonas viridans

“…However, the unambiguous ring topologies in VdsA1, between Dha-11 and Dha-15 with Cys-16 and Cys-18, cannot be assigned with mass spectrometry alone. The formation of lanthionine rings between neighboring Dha/Dhb residues and a cognate cysteine residue has been reported in mersacidin, and therefore, a lanthionine bond between Dha15 and C16 in VdsA1 cannot be ruled out. , The most likely topology has been depicted based on the thallasomonasin A structure elucidated recently via NMR spectroscopy . VdsA1 must undergo peak splitting caused by some changes to its tertiary structure, as samples P1A and P1B have identical fragmentation spectra.…”

“…These lanthipeptides have not been isolated from the native producers T. viridans XOM25T and T. actiniatium A5K-106(T) or from P. lusitanus NL19. 13,14 These findings have led to a case study demonstrating that genomes from Gram-negative bacteria are a rich source of novel but seemingly cryptic lanthipeptides with largely uncharacterized but clearly important biological roles. 15 Phylogenetically, the VdsC and VdsB proteins are classified as class I lanthipeptides due to their independent nature and homology (Figures 1a and 2).…”

“…actiniatium A5K-106­(T) or from P. lusitanus NL19. , These findings have led to a case study demonstrating that genomes from Gram-negative bacteria are a rich source of novel but seemingly cryptic lanthipeptides with largely uncharacterized but clearly important biological roles …”