scholarly journals Biosynthesis-Guided Discovery of Enteropeptins, Unusual Sactipeptides Containing an N-Methylornithine

Author(s):  
Kenzie A. Clark ◽  
Brett C. Covington ◽  
Mohammad R. Seyedsayamdost

The combination of next-generation DNA sequencing technologies and bioinformatics have revitalized natural product discovery. Using a new bioinformatic search strategy, we recently identified ~600 gene clusters in animal microbiomes that code for ribosomal peptide natural products synthesized by radical S-adenosylmethionine enzymes. These grouped into 16 subfamilies and pointed to an unexplored microbiome biosynthetic landscape. Herein, we report the structure, biosynthesis, and function of one of these natural product groups, that we term enteropeptins, from the gut microbe Enterococcus cecorum. We elucidate three novel reactions, each catalyzed by a different family of metalloenzymes, in the biosynthesis of enteropeptins. Among these, we characterize the founding member of a widespread superfamily of Fe-S-containing methyltransferases, which, together with a di-Mn-dependent arginase, installs an N-methylornithine in the peptide sequence. Biological assays with the mature product revealed bacteriostatic activity only against the producing strain, extending an emerging theme of fratricidal or self-inhibitory metabolites in microbiome firmicutes.

2016 ◽  
Vol 69 (2) ◽  
pp. 129 ◽  
Author(s):  
John A. Kalaitzis ◽  
Shane D. Ingrey ◽  
Rocky Chau ◽  
Yvette Simon ◽  
Brett A. Neilan

Historically microbial natural product biosynthesis pathways were elucidated mainly by isotope labelled precursor directed feeding studies. Now the genetics underpinning the assembly of microbial natural products biosynthesis is so well understood that some pathways and their products can be predicted from DNA sequences alone. The association between microbial natural products and their biosynthesis gene clusters is now driving the field of ‘genetics guided natural product discovery’. This account overviews our research into cyanotoxin biosynthesis before the genome sequencing era through to some recent discoveries resulting from the mining of Australian biota for natural product biosynthesis pathways.


Author(s):  
M. Boublik ◽  
R.M. Wydro ◽  
W. Hellmann ◽  
F. Jenkins

Ribosomes are ribonucleoprotein particles necessary for processing the genetic information of mRNA into proteins. Analogy in composition and function of ribosomes from diverse species, established by biochemical and biological assays, implies their structural similarity. Direct evidence obtained by electron microscopy seems to be of increasing relevance in understanding the structure of ribosomes and the mechanism of their role in protein synthesis.The extent of the structural homology between prokaryotic and eukaryotic ribosomes has been studied on ribosomes of Escherichia coli (E.c.) and Artemia salina (A.s.). Despite the established differences in size and in the amount and proportion of ribosomal proteins and RNAs both types of ribosomes show an overall similarity. The monosomes (stained with 0.5% aqueous uranyl acetate and deposited on a fine carbon support) appear in the electron micrographs as round particles with a diameter of approximately 225Å for the 70S E.c. (Fig. 1) and 260Å for the 80S A.s. monosome (Fig. 2).


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chong Chu ◽  
Rebeca Borges-Monroy ◽  
Vinayak V. Viswanadham ◽  
Soohyun Lee ◽  
Heng Li ◽  
...  

AbstractTransposable elements (TEs) help shape the structure and function of the human genome. When inserted into some locations, TEs may disrupt gene regulation and cause diseases. Here, we present xTea (x-Transposable element analyzer), a tool for identifying TE insertions in whole-genome sequencing data. Whereas existing methods are mostly designed for short-read data, xTea can be applied to both short-read and long-read data. Our analysis shows that xTea outperforms other short read-based methods for both germline and somatic TE insertion discovery. With long-read data, we created a catalogue of polymorphic insertions with full assembly and annotation of insertional sequences for various types of retroelements, including pseudogenes and endogenous retroviruses. Notably, we find that individual genomes have an average of nine groups of full-length L1s in centromeres, suggesting that centromeres and other highly repetitive regions such as telomeres are a significant yet unexplored source of active L1s. xTea is available at https://github.com/parklab/xTea.


mSystems ◽  
2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Daniela B. B. Trivella ◽  
Rafael de Felicio

ABSTRACT Natural products are the richest source of chemical compounds for drug discovery. Particularly, bacterial secondary metabolites are in the spotlight due to advances in genome sequencing and mining, as well as for the potential of biosynthetic pathway manipulation to awake silent (cryptic) gene clusters under laboratory cultivation. Further progress in compound detection, such as the development of the tandem mass spectrometry (MS/MS) molecular networking approach, has contributed to the discovery of novel bacterial natural products. The latter can be applied directly to bacterial crude extracts for identifying and dereplicating known compounds, therefore assisting the prioritization of extracts containing novel natural products, for example. In our opinion, these three approaches—genome mining, silent pathway induction, and MS-based molecular networking—compose the tripod for modern bacterial natural product discovery and will be discussed in this perspective.


2021 ◽  
Author(s):  
Rong Huang Huang ◽  
Tingting Li Li ◽  
Xi Yong Yong ◽  
Huling Wen Wen ◽  
Xing Zhou Zhou ◽  
...  

Abstract 15-Lipoxygenase-2(15-LOX-2) is thought to regulate inflammation and immunological function however, its mechanisms of action are still unclear. Furthermore, it has been reported that salidroside has anti inflammatory properties , but its role in macrophage function has not been understood yet In this study, we aimed to determine how 15-LOX-2 expression level s affect the function of macrophages and the effect of salidroside on 15-LOX-2 deficient macrophages We used multiple functional genetic strategies to determine 15-LOX-2 function in macrophages. 15-LOX-2 deficiency promotes phagocytosis and proliferation of macrophages and impairs their apoptosis Mechanistically, t he expression levels of cyclophilinB (CypB) were upregulated in 15-LOX-2 deficient Ana 1 macrophages, whereas those of caspase 3 were down regulated. Furthermore, RNA-seq analysis showed that inflammation, complement, and TNF-α signaling pathway s were all activated in 15-LOX-2 deficient Ana 1 macrophages. Treatment of 15-LOX-2 deficient macrophages with salidroside, a natural product derived from Rhodiola species, effectively reversed the effects of 15-LOX-2 deficiency on caspase 3 and CypB levels, as well as on apoptosis and proliferation. In conclusion, our study shows that there is a newly identified link between 15-LOX-2 deficiency and salidroside in regulating macrophage survival, proliferation, and function. Salidroside may be a promising therapeutic strategy for treating inflammation related diseases resulting from 15-LOX-2 deficiency.


1999 ◽  
Vol 63 (2) ◽  
pp. 266-292 ◽  
Author(s):  
Carol L. Bender ◽  
Francisco Alarcón-Chaidez ◽  
Dennis C. Gross

SUMMARY Coronatine, syringomycin, syringopeptin, tabtoxin, and phaseolotoxin are the most intensively studied phytotoxins of Pseudomonas syringae, and each contributes significantly to bacterial virulence in plants. Coronatine functions partly as a mimic of methyl jasmonate, a hormone synthesized by plants undergoing biological stress. Syringomycin and syringopeptin form pores in plasma membranes, a process that leads to electrolyte leakage. Tabtoxin and phaseolotoxin are strongly antimicrobial and function by inhibiting glutamine synthetase and ornithine carbamoyltransferase, respectively. Genetic analysis has revealed the mechanisms responsible for toxin biosynthesis. Coronatine biosynthesis requires the cooperation of polyketide and peptide synthetases for the assembly of the coronafacic and coronamic acid moieties, respectively. Tabtoxin is derived from the lysine biosynthetic pathway, whereas syringomycin, syringopeptin, and phaseolotoxin biosynthesis requires peptide synthetases. Activation of phytotoxin synthesis is controlled by diverse environmental factors including plant signal molecules and temperature. Genes involved in the regulation of phytotoxin synthesis have been located within the coronatine and syringomycin gene clusters; however, additional regulatory genes are required for the synthesis of these and other phytotoxins. Global regulatory genes such as gacS modulate phytotoxin production in certain pathovars, indicating the complexity of the regulatory circuits controlling phytotoxin synthesis. The coronatine and syringomycin gene clusters have been intensively characterized and show potential for constructing modified polyketides and peptides. Genetic reprogramming of peptide and polyketide synthetases has been successful, and portions of the coronatine and syringomycin gene clusters could be valuable resources in developing new antimicrobial agents.


Author(s):  
Nadège Guiglielmoni ◽  
Ramón Rivera-Vicéns ◽  
Romain Koszul ◽  
Jean-François Flot

Non-vertebrate species represent about ~95% of known metazoan (animal) diversity. They remain to this day relatively unexplored genetically, but understanding their genome structure and function is pivotal for expanding our current knowledge of evolution, ecology and biodiversity. Following the continuous improvements and decreasing costs of sequencing technologies, many genome assembly tools have been released, leading to a significant amount of genome projects being completed in recent years. In this review, we examine the current state of genome projects of non-vertebrate animal species. We present an overview of available sequencing technologies, assembly approaches, as well as pre and post-processing steps, genome assembly evaluation methods, and their application to non-vertebrate animal genomes.


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