We describe the production and screening of a genetically encoded library of 106 lanthipeptides in Escherichia coli using the substrate-tolerant lanthipeptide synthetase ProcM. This plasmidencoded library was combined with a bacterial reverse two-hybrid system for the interaction of the HIV p6 protein with the UEV domain of the human TSG101 protein, a critical protein–protein interaction for HIV budding from infected cells. Using this approach, we identified an inhibitor of this interaction from the lanthipeptide library, whose activity was verified in vitro and in cell-based virus-like particle budding assays. Given the variety of lanthipeptide backbone scaffolds that may be produced with ProcM, this method may be used for the generation of genetically encoded libraries of natural product-like lanthipeptides containing substantial structural diversity. Such libraries may be combined with any cell-based assay for the identification of lanthipeptides with new biological activities.
Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a major class of natural products with a high degree of structural diversity and a wide variety of bioactivities. Understanding the biosynthetic machinery of these RiPPs will benefit the discovery and development of new molecules with potential pharmaceutical applications. In this review, we discuss the features of the biosynthetic pathways to different RiPP classes, and propose mechanisms regarding recognition of the precursor peptide by the posttranslational modification enzymes. We propose that the leader peptides function as allosteric regulators that bind the active form of the biosynthetic enzymes in a conformational selection process. We also speculate how enzymes that generate polycyclic products of defined topologies may have been selected for during evolution.
a b s t r a c tPerfluoroalkyl acids (PFAAs) are emerging contaminants that have raised great concern in recent years. While PFAAs manufacturing becomes regulated in developed countries, production has been partly shifted to China. Eight fluoropolymer manufacturing facilities located in the South Bohai coastal region, one of the most populated areas of China, have been used to manufacture PFAA-related substances since 2001. The environmental consequence of the intensive production of PFAAs in this region remains largely unknown. We analyzed 17 PFAAs in twelve coastal rivers of this region, and found staggeringly high concentrations of perfluorooctanoic acid (PFOA) ranging from 0.96 to 4534.41 ng/L. The highest concentration was observed in the Xiaoqing River which received effluents from certain fluoropolymer facilities. Principal component analysis indicated similar sources of several perfluoroalkyl carboxylic acids (PFCAs) in all rivers, which indicated that atmospheric transport, wastewater treatment and surface runoff also acted as important supplements to direct discharge to surface water.
Lanthionine-containing peptides (lanthipeptides)
are a rapidly
growing family of polycyclic peptide natural products belonging to
the large class of ribosomally synthesized and post-translationally
modified peptides (RiPPs). These compounds are widely distributed
in taxonomically distant species, and their biosynthetic systems and
biological activities are diverse. A unique example of lanthipeptide
biosynthesis is the prochlorosin synthetase ProcM from the marine
cyanobacterium Prochlorococcus MIT9313,
which transforms up to 29 different precursor peptides (ProcAs) into
a library of lanthipeptides called prochlorosins (Pcns) with highly
diverse sequences and ring topologies. Here, we show that many ProcM-like
enzymes from a variety of bacteria have the capacity to carry out
post-translational modifications on highly diverse precursor peptides,
providing new examples of natural combinatorial biosynthesis. We also
demonstrate that the leader peptides come from different evolutionary
origins, suggesting that the combinatorial biosynthesis is tied to
the enzyme and not a specific type of leader peptide. For some precursor
peptides encoded in the genomes, the leader peptides apparently have
been truncated at the N-termini, and we show that these N-terminally
truncated peptides are still substrates of the enzymes. Consistent
with this hypothesis, we demonstrate that about two-thirds of the
ProcA N-terminal sequence is not essential for ProcM activity. Our
results also highlight the potential of exploring this class of natural
products by genome mining and bioengineering.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.