Discovery and biosynthesis of persiathiacins: Unusual polyglycosylated thiopeptides active against multi-drug resistant tuberculosis

Abstract

Thiopeptides are ribosomally synthesized and posttranslationally modified peptides (RiPPs) that exhibit a range of useful biological activities. Herein, antimicrobial activity screens with a library of Actinobacteria extracts led to discovery of the novel thiopeptide antibiotics persiathiacins A and B, originating from Actinokineospora sp. UTMC 2475 and Actinokineospora sp. UTMC 2448. Persiathiacin A displayed potent activity against methicillin-resistant Staphylococcus aureus (MRSA) and several Mycobacterium tuberculosis strains, including drug-resistant and multidrug-resistant clinical isolates, but no significant toxicity towards an ovarian cancer cell line. On the basis of in vitro translation assays, the observed antibacterial activity could be attributed to inhibition of ribosomal protein biosynthesis. Philipimycin is the only other polyglycosylated thiopeptide reported and nothing is known about its biosynthesis. We therefore sequenced and analysed the genome of Actinokineospora sp. UTMC 2448 to identify the biosynthetic gene cluster responsible for persiathiacin production. Through in vitro and in vivo experiments, we confirmed the role of this gene cluster in persiathiacin biosynthesis and identified a cytochrome P450 enzyme that introduces a site for deoxysugar attachment via thiazole hydroxylation. On the basis of several promising characteristics, persiathiacins A and B are good candidates from which new therapeutics may be engineered.

Selective biosynthesis of a rhamnosyl nosiheptide by a novel bacterial rhamnosyltransferase

“…AHMU CJ021 (Xie et al., 2020 ), Actinokineospora sp. UTMC 2448 (Dashti et al., 2022 ), Nocardia sp. ATCC 202099 (Ding et al., 2010 ), Nocardia arthritidis (Herisse et al., 2020 ) and Micromonospora sp.…”

Cytochromes P450 Associated with the Biosyntheses of Ribosomally Synthesized and Post-translationally Modified Peptides

“…Other thiostrepton-like thiopeptides such as siomycin (51), 41 thiopeptin (52), 37,38 Sch18640 (53), and saalfelduracin (54) 42 also contain similar quinaldic acid and dihydroxylation at isoleucine (Figure 5C), similar to the previously mentioned thiostrepton (50). In accordance with their structural similarities, homologous proteins of TsrP and TsrR are encoded in their BGCs, ranging from 52% to 74% for TsrP and from 50% to 79% for TsrR in sequence identities.…”

“…Benefiting from the high resemblance of nocathiacin ( 62 ) and persiathiacin ( 63 ) in structures and biosynthetic machinery, these five P450s are assumed to perform analogous functions as their homologues in nocathiacin biosynthesis. The remnant P450 PerX catalyzes thiazole hydroxylation of nosiheptide both in vivo and in vitro (Figure B), although the structure of the product has not been fully characterized . Persiathiacins ( 63 ) by far may represent the highest number of P450s involved in RiPP biosynthesis.…”

“… b Homologous proteins of NosB and NosC are also encoded in the BGCs of nocathiacin ( 62 ) (refs , ) and persiathiacin ( 63 ) (ref ). …”

“… a Homologous proteins of TsrP and TsrR are also encoded in the BGCs of siomycin ( 51 ) (ref ), thiopeptin ( 52 ) (refs , ), Sch18640 ( 53 ) (ref ), and saalfelduracin ( 54 ) (ref ). b Homologous proteins of NosB and NosC are also encoded in the BGCs of nocathiacin ( 62 ) (refs , ) and persiathiacin ( 63 ) (ref ). c Homologous proteins of NocV, NocU and NocT are also encoded in the BGC of persiathiacin ( 63 ) (ref ). d Homologous proteins of McmI are also encoded in the BGCs of YM-216391 ( 121 ) (ref ), aurantizolicin ( 122 ) (ref ), and curacozole ( 123 ) (ref ). …”