Kistamicin biosynthesis reveals the biosynthetic requirements for production of highly crosslinked glycopeptide antibiotics

Abstract

Kistamicin is a divergent member of the glycopeptide antibiotics, a structurally complex class of important, clinically relevant antibiotics often used as the last resort against resistant bacteria. The extensively crosslinked structure of these antibiotics that is essential for their activity makes their chemical synthesis highly challenging and limits their production to bacterial fermentation. Kistamicin contains three crosslinks, including an unusual 15-membered A- O -B ring, despite the presence of only two Cytochrome P450 Oxy enzymes thought to catalyse formation of such crosslinks within the biosynthetic gene cluster. In this study, we characterise the kistamicin cyclisation pathway, showing that the two Oxy enzymes are responsible for these crosslinks within kistamicin and that they function through interactions with the X-domain, unique to glycopeptide antibiotic biosynthesis. We also show that the kistamicin OxyC enzyme is a promiscuous biocatalyst, able to install multiple crosslinks into peptides containing phenolic amino acids.

A cyclopeptide and three oligomycin-class polyketides produced by an underexplored actinomycete of the genus Pseudosporangium

“…The bioactivities of compounds 1-4 were examined in antimicrobial and cytotoxicity assays ( [29,30] and TMC95A-D from an ascomycetous fungus Apiospora montagnei [31]; the (E)-2,3-dehydroadipyl appendage in compound 2 is unprecedented in natural products, only to see its (Z)-isomer in a siderophore of Mycobacterium avium [32]; the side chain on the spiroacetal rings in compounds 2-4 lack hydroxylation at C-31, which is the common modification shared with all oligomycin class antibiotics (oligomycin [33], dunaimycins [34], rutamycins [35], ossamycin [36], neomaclafungins [37], and IB-96212 [38]) and related polyketides with ring-truncation (ushikulides [39], yokonolides [40,41], A59770A [42], dunaimycins [34]) or expansion (neaumycins [43]) ( Figure 8). All these compounds, except for maclafungin [44], the producer of which was not identified, are metabolites of Streptomyces [33][34][35][36] or conventional rare actinomycetes [37,38].…”

New Molecular Tools for Regulation and Improvement of A40926 Glycopeptide Antibiotic Production in Nonomuraea gerenzanensis ATCC 39727

“…Apart from some reports on cultivating and manipulating the industrially valuable A40926 producer N. gerenzanensis (Stinchi et al, 2003(Stinchi et al, , 2006Marcone et al, 2010a,b,c;Alt et al, 2019) and the kistamicin producer Nonomuraea sp. ATCC 55076 (Greule et al, 2019), we are not aware of any other attempt to develop genetic tools for manipulating Nonomuraea spp. However, some other glycopeptide producers, like A. teichomyceticus, already possess well-developed toolkits for genetic manipulation which has greatly simplified investigations in these strains (Horbal et al, 2013;Yushchuk et al, 2016).…”

Understanding the early stages of peptide formation during the biosynthesis of teicoplanin and related glycopeptide antibiotics

“…Whilst the presence of atypical epimerase domains within NRPS has been reported [41,42], the mechanism behind this epimerisation in GPA biosynthesis is not yet fully clarified. A further example of an atypical dual C/E‐domain that also does not cluster with traditional dual C/E‐domains [40] has also been postulated in M4 in the NRPS producing kistamicin, a type V GPA that has diverged significantly from teicoplanin and the majority of other GPAs [43]. Whilst Hpg is the substrate that is epimerised for both Tcp/Dbv M1 and kistamicin M4, and the relative ease of racemisation of such residues allows uncommon NRPS domain activity to occur (e.g.…”

“…Hence, whilst our results now strongly support epimerisation of the first amino acid via the actions of the initial C‐domain in GPA biosynthesis, the mechanism by which this is accomplished remains unclear and likely will require structural characterisation. This also adds to the rapidly growing range of roles in NRPS biosynthesis that C‐domains can play in peptide assembly beyond simple peptide bond formation [4,8,43,45–50.…”