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Bioinformatic Expansion and Discovery of Thiopeptide Antibiotics
dataset
posted on 2018-07-09, 00:00 authored by Christopher
J. Schwalen, Graham A. Hudson, Bryce Kille, Douglas A. MitchellThiopeptides
are members of the ribosomally synthesized and post-translationally
modified peptide family of natural products. Most characterized thiopeptides
display nanomolar potency toward Gram-positive bacteria by blocking
protein translation with several being produced at the industrial
scale for veterinary and livestock applications. Employing our custom
bioinformatics program, RODEO, we expand the thiopeptide family of
natural products by a factor of four. This effort revealed many new
thiopeptide biosynthetic gene clusters with products predicted to
be distinct from characterized thiopeptides and identified gene clusters
for previously characterized molecules of unknown biosynthetic origin.
To further validate our data set of predicted thiopeptide biosynthetic
gene clusters, we isolated and characterized a structurally unique
thiopeptide featuring a central piperidine and rare thioamide moiety.
Termed saalfelduracin, this thiopeptide displayed potent antibiotic
activity toward several drug-resistant Gram-positive pathogens. A
combination of whole-genome sequencing, comparative genomics, and
heterologous expression experiments confirmed that the thioamide moiety
of saalfelduracin is installed post-translationally by the joint action
of two proteins, TfuA and YcaO. These results reconcile the previously
unknown origin of the thioamide in two long-known thiopeptides, thiopeptin
and Sch 18640. Armed with these new insights into thiopeptide chemical-genomic
space, we provide a roadmap for the discovery of additional members
of this natural product family.