Identification, Cloning and Heterologous Expression of the Gene Cluster Directing RES-701-3, -4 Lasso Peptides Biosynthesis from a Marine Streptomyces Strain.

Daniel Oves-Costales,Olga Genilloud,Marina Sánchez-Hidalgo,Jesús Martín

doi:10.3390/md18050238

Abstract

RES-701-3 and RES-701-4 are two class II lasso peptides originally identified in the fermentation broth of Streptomyces sp. RE-896, which have been described as selective endothelin type B receptor antagonists. These two lasso peptides only differ in the identity of the C-terminal residue (tryptophan in RES-701-3, 7-hydroxy-tryptophan in RES-701-4), thus raising an intriguing question about the mechanism behind the modification of the tryptophan residue. In this study, we describe the identification of their biosynthetic gene cluster through the genome mining of the marine actinomycete Streptomyces caniferus CA-271066, its cloning and heterologous expression, and show that the seven open reading frames (ORFs) encoded within the gene cluster are sufficient for the biosynthesis of both lasso peptides. We propose that ResE, a protein lacking known putatively conserved domains, is likely to play a key role in the post-translational modification of the C-terminal tryptophan of RES-701-3 that affords RES-701-4. A BLASTP search with the ResE amino acid sequence shows the presence of homologues of this protein in the genomes of eight other Streptomyces strains, which also harbour the genes encoding the RES-701-3, -4 precursor peptide, split-B proteins and ATP-dependent lactam synthetase required for the biosynthesis of these compounds.

Highlights

Lasso peptides are a class of ribosomally synthesised and post-translationally modified peptides (RiPPs) natural products produced by the bacterial domain [1,2]
Careful examination of one of the RiPP gene clusters strongly suggested that it directed the biosynthesis of at least RES-701-3, based on the amino acid sequence predicted to be encoded by the precursor peptide gene resA (Figure 2)
Post-translational modifications are unusual in lasso peptides, a few examples have been reported recently, including the C-terminal phosphorylation in paeninodin [27], citrullination in citrulassin A [14], acetylation in albusnodin [28], C-terminal methylation of lassomycin and lassomycin-like lasso peptides [29,30], and the epimerization of the α-carbon from the C-terminal amino acid residue in MS-271 [31]

Summary

Introduction

Lasso peptides are a class of ribosomally synthesised and post-translationally modified peptides (RiPPs) natural products produced by the bacterial domain [1,2]. They have been shown to possess a wide range of biological properties, including antimicrobial activity against Gram-negative pathogens in the case of capistruin [3] and microcin J25 [4], antimicrobial activity against Gram-positive pathogens such as that exerted by siamycin-I [5] and the inhibition of HIV replication displayed in cell cultures by RP71955 [6]. A striking feature of lasso peptides, which sets them apart from other RiPPs, is their unusual topology.

Methods

Results

Conclusion