Lanthipeptide Synthetases Participate the Biosynthesis of 2-Aminovinyl-Cysteine Motifs in Thioamitides

Abstract

Thioamitides are a group of ribosomally synthesized and post-translational modified peptides with potent antiproliferative and proapoptotic activities. Their biosynthesis remains largely unknown, especially for the characteristic C-terminal 2-aminovinyl-Cysteine (AviCys) motifs. Herein, we report the discovery that homologs of class III lanthipeptide synthetases (LanKCts)encoded outside putative thioamitide biosynthetic gene clusters (BGCs) fully dehydrate the precursor peptides. Remarkably, LanKCt enzymes bind tightly to cysteine decarboxylases encoded inside thioamitide BGCs, and the resulting complex complete the macrocyclization of AviCys rings. Furthermore, LanKCt enzymes are present in the genomes of many thioamitide-producing strains and are functional when in complex with cysteine decarboxylases to produce AviCys macrocycles. Thus, our study reveals the participation of lanthipeptide synthetases as a general strategy for dehydration and AviCys formation during thioamitides biosynthesis and thus paves the way for the bioengineering of this class of bioactive natural products.

Aminovinyl Cysteine Containing Peptides: A Unique Motif That Imparts Key Biological Activity

“…These enzymes dehydrate the precursor peptide and form a complex with the cysteine decarboxylase to produce the Avi(Me)Cys macrocycle. 46 …”

“…This natural product displayed potent cytotoxic properties against rat fibroblasts transformed with adenovirus oncogenes with an IC 50 = 3.9 ng/mL . Since then, nine other Avi­(Me)­Cys-containing thioamitides have been discovered, with all of them displaying anticancer activity across multiple cell lines. ,,,, Thioviridamide acts as an apoptosis inducer by targeting the F 1 F 0 -ATP synthase and inducing the integrated stress response, a cellular process that downregulates protein synthesis in response to internal or environmental stresses such as amino acid deprivation or endoplasmic reticulum stress . Thioholgamide A, which was discovered in 2020 by Kiemer et al, also targets the ATP synthase which causes antiproliferative and cytotoxic effects on cancer cells .…”

“…Apart from that, little is known about the biosynthetic pathway, although it has been postulated that enzymes similar to those found in the class III lanthipeptides (LanKC t ) are responsible for forming the Avi­(Me)­Cys structure. These enzymes dehydrate the precursor peptide and form a complex with the cysteine decarboxylase to produce the Avi­(Me)­Cys macrocycle …”

“…NRRL S-87 cytotoxic (anticancer) thioholgamides A and B 44 Streptomyces malayseiense antiproliferative and cytotoxic (anticancer) thiostreptamide S4 45 Streptomyces sp. NRRL S-4 anticancer (specific activity yet to be reported) thiosparsoamide 46 Streptomyces sparsogenes thioalbamide 47 Amycolatopsis alba JBIR-140 48 Streptomyces avermitilis TVA-YJ-1 49 Streptomyces laurentii lipolanthine microvionin 50 Microbacterium arborescens MRSA (G+), Streptococcus pneumoniae (G+) nocavionin 50 Nocardia terpenica not reported goadvionins 51 Streptomyces sp. TP-A0584 Staphylococcus aureus (G+), Bacillus subtilis (G+), Micrococcus luteus (G+) lanthidin cacaoidin 52 Streptomyces cacaoi MRSA (G+), Clostridium difficile (G+), Staphylococcus simulans (G+) containing microbisporicin sequester lipid II by forming lanthipeptide−lipid II complexes.…”

“… Chemical structures of Avi(Me)Cys-containing peptides of the thioamitide family; thioholgamide A ( 19 ), 44 thioviridamide ( 20 ), 5 thiostreptamide S4 ( 21 ), 45 thioholgamide B ( 22 ), 44 thiosparsoamide ( 23 ), 46 JBIR-140 ( 24 ), 48 TVA-YJ-4 and 5 (epimers at α-hydroxyamide) ( 25 ), 43 thioalbamide ( 26 ), 47 TVA-YJ-6 ( 27 ), 43 and TVA-YJ-1 ( 28 ). 43 Pink = Avi(Me)Cys.…”