scholarly journals Catalytic Use of a Leader Peptide in the Biosynthesis of 3-Thiaglutamate

2018 ◽  
Author(s):  
Michael A. Funk ◽  
Chi Ting ◽  
Wilfred A. van der Donk

AbstractSmall molecule natural products are key modulators of many types of intra- and interspecies communication. The availability of genome sequences allows the discovery of pathways to previously unknown natural products. We describe here a pathway in which a ribosomally synthesized small peptide serves as a catalytic scaffold on which a small-molecule anti-metabolite is biosynthesized in Pseudomonas syringae. First, a cysteine residue is transferred from Cys-tRNA to the C-terminus of the peptide, a reaction that replaces ribosomal protein synthesis. Then, a translocation of the cysteine thiol from the β-carbon to the α-carbon is catalyzed by an oxidase that removes the β-carbon as formate. The resulting thiol is carboxymethylated and proteolysis releases 3-thiaglutamate, in the process regenerating the peptide scaffold. This pathway features three previously unknown biochemical processes.


2013 ◽  
Vol 9 ◽  
pp. 1768-1773 ◽  
Author(s):  
Dinesh Simkhada ◽  
Huitu Zhang ◽  
Shogo Mori ◽  
Howard Williams ◽  
Coran M H Watanabe

At least 65% of all small molecule drugs on the market today are natural products, however, re-isolation of previously identified and characterized compounds has become a serious impediment to the discovery of new bioactive natural products. Here, genetic knockout of an unusual non-ribosomal peptide synthetase (NRPS) C-PCP-C module, aziA2, is performed resulting in the accumulation of the secondary metabolite, dimethyl furan-2,4-dicarboxylate. The cryptic metabolite represents the first non-azinomycin related compound to be isolated and characterized from the soil bacterium, S. sahachiroi. The results from this study suggest that abolishing production of otherwise predominant natural products through genetic knockout may constitute a means to “activate” the production of novel secondary metabolites that would otherwise lay dormant within microbial genome sequences.



2021 ◽  
Vol 9 ◽  
Author(s):  
Yunliang Chen ◽  
Jinxiu Wang ◽  
Guoquan Li ◽  
Yunpeng Yang ◽  
Wei Ding

Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a growing class of natural products that benefited from genome sequencing technology in the past two decades. RiPPs are widely distributed in nature and show diverse chemical structures and rich biological activities. Despite the various structural characteristic of RiPPs, they follow a common biosynthetic logic: a precursor peptide containing an N-terminal leader peptide and a C-terminal core peptide; in some cases,a follower peptide is after the core peptide. The precursor peptide undergoes a series of modification, transport, and cleavage steps to form a mature natural product with specific activities. Sactipeptides (Sulfur-to-alpha carbon thioether cross-linked peptides) belong to RiPPs that show various biological activities such as antibacterial, spermicidal and hemolytic properties. Their common hallmark is an intramolecular thioether bond that crosslinks the sulfur atom of a cysteine residue to the α-carbon of an acceptor amino acid, which is catalyzed by a rSAM enzyme. This review summarizes recent achievements concerning the discovery, distribution, structural elucidation, biosynthesis and application prospects of sactipeptides.



Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1110 ◽  
Author(s):  
Przemysław Duda ◽  
Shaw M. Akula ◽  
Stephen L. Abrams ◽  
Linda S. Steelman ◽  
Alberto M. Martelli ◽  
...  

Glycogen synthase kinase 3 (GSK-3) is a serine/threonine (S/T) protein kinase. Although GSK-3 originally was identified to have functions in regulation of glycogen synthase, it was subsequently determined to have roles in multiple normal biochemical processes as well as various disease conditions. GSK-3 is sometimes referred to as a moonlighting protein due to the multiple substrates and processes which it controls. Frequently, when GSK-3 phosphorylates proteins, they are targeted for degradation. GSK-3 is often considered a component of the PI3K/PTEN/AKT/GSK-3/mTORC1 pathway as GSK-3 is frequently phosphorylated by AKT which regulates its inactivation. AKT is often active in human cancer and hence, GSK-3 is often inactivated. Moreover, GSK-3 also interacts with WNT/β-catenin signaling and β-catenin and other proteins in this pathway are targets of GSK-3. GSK-3 can modify NF-κB activity which is often expressed at high levels in cancer cells. Multiple pharmaceutical companies developed small molecule inhibitors to suppress GSK-3 activity. In addition, various natural products will modify GSK-3 activity. This review will focus on the effects of small molecule inhibitors and natural products on GSK-3 activity and provide examples where these compounds were effective in suppressing cancer growth.



2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Emmanuel Matabaro ◽  
Hannelore Kaspar ◽  
Paul Dahlin ◽  
Daniel L. V. Bader ◽  
Claudia E. Murar ◽  
...  

AbstractBackbone N-methylation and macrocyclization improve the pharmacological properties of peptides by enhancing their proteolytic stability, membrane permeability and target selectivity. Borosins are backbone N-methylated peptide macrocycles derived from a precursor protein which contains a peptide α-N-methyltransferase domain autocatalytically modifying the core peptide located at its C-terminus. Founding members of borosins are the omphalotins from the mushroom Omphalotus olearius (omphalotins A-I) with nine out of 12 L-amino acids being backbone N-methylated. The omphalotin biosynthetic gene cluster codes for the precursor protein OphMA, the protease prolyloligopeptidase OphP and other proteins that are likely to be involved in other post-translational modifications of the peptide. Mining of available fungal genome sequences revealed the existence of highly homologous gene clusters in the basidiomycetes Lentinula edodes and Dendrothele bispora. The respective borosins, referred to as lentinulins and dendrothelins are naturally produced by L. edodes and D. bispora as shown by analysis of respective mycelial extracts. We produced all three homologous peptide natural products by coexpression of OphMA hybrid proteins and OphP in the yeast Pichia pastoris. The recombinant peptides differ in their nematotoxic activity against the plant pathogen Meloidogyne incognita. Our findings pave the way for the production of borosin peptide natural products and their potential application as novel biopharmaceuticals and biopesticides.



2021 ◽  
Vol 21 (17) ◽  
pp. 1517-1518
Author(s):  
Dharmendra Kumar Yadav

The discovery and utilization of novel metabolites from natural sources are gaining momentum in the present era. The drug discovery programs have witnessed a remarkable shift from conventional medicines to exploiting natural products and their “value addition”, for treating lifethreatening diseases. The global outbreak of life-threatening diseases namely Ebola, SARS,including infections of the bloodstream (bacteremia), heart valves (endocarditis), lungs (pneumonia), and brain (meningitis) and AIDS calls for a more targeted approach to effectively combat the emerging diseases. In the present scenario, natural products and their extracts are being explored extensively for the treatment of various life threatening diseases. In this thematic issue, several review articles contributed by the scientist and researchers in the different areas of medicinal chemistry, synthetic chemistry, new emerging multi-drug targets were collected. This issue begins with a review article on the “Chemistry and Pharmacology of Natural Catechins from Camellia sinensis as anti-MRSA agents” by Gaur et al. and focuses on the spread of MRSA strains is of great concern because of limited treatment options for staphylococcal infections, since these strains are resistant to the entire class of β-lactam antibiotics. In addition, MRSA exhibits resistance to other classes of antimicrobial agents such as fluoroquinolones, cephalosporins, aminoglycosides, macrolide and even glycopeptides (vancomycin and teicoplanine), leading to the emergence of resistant strains such as glycopeptide intermediate (GISA) and resistant strain (GRSA) of S. aureus. In this review, chemical constituents responsible for the anti-MRSA activity of tea are explored [1]. The next article of this issue is a review article on the “Recent Advancements in the Synthesis and Chemistry of Benzofused Nitrogen- and Oxygen-based Bioactive Heterocycles” by Sharma et al. which focuses on medicinal importance of these bioactive benzo-fused heterocycles; special attention has been given to their synthesis as well as medicinal/pharmaceutical properties in detail [2]. “Trends in pharmaceutical design of Endophytes as anti-infective,” by Tiwari et al., is the third article in this issue. The review focused on the meta-analysis of bioactive metabolite production from endophytes, extensively discussing the bioprospection of natural products for pharmaceutical applications. In light of the emerging importance of endophytes as antiinfective agents, an exploration of the pharmaceutical design of novel chemical entities and analogues has enabled efficient and cost-effective drug discovery programs. However, bottlenecks in endophytic biology and research requires a better understanding of endophytic dynamics and mechanism of bioactive metabolite production towards a sustainable drug discovery program [3]. The last article of this issue is also research article on “Recent development of tetrahydro-quinoline/isoquinoline based compounds as anticancer agents” by Yadav et al. The article reported the synthesis of potent tetrahydroquinoline/isoquinoline molecules of the last 10 years with their anticancer properties in various cancer cell lines and stated their half-maximal inhibitory concentration (IC50). In addition, we also considered the discussion of molecular docking and structural activity relationship wherever provided to understand the possible mode of activity an target involved and structural features responsible for the better activity, so the reader can directly find detail for designing new anticancer agents. [4]. Finally I would like to thank all authors who contributed to this issue, titled “Recent advances on small molecule medicinal chemistry to treat human diseases”.



2021 ◽  
Vol 10 (17) ◽  
Author(s):  
Takashi Fujikawa ◽  
Yuichi Takikawa ◽  
Yasuhiro Inoue

ABSTRACT Pseudomonas cannabina pv. alisalensis and Pseudomonas syringae pv. maculicola cause bacterial leaf blight and bacterial leaf spot of crucifers (Brassicaceae). Both pathogens are threats to the cultivation of cruciferous crops. Here, we sequenced two strains of each pathogen, which will contribute to the development of countermeasures for the above diseases.



MedChemComm ◽  
2017 ◽  
Vol 8 (6) ◽  
pp. 1220-1224 ◽  
Author(s):  
Hamid R. Nasiri ◽  
Philipp Mracek ◽  
Steffen K. Grimm ◽  
Janine Gastaldello ◽  
Adrian Kolodzik ◽  
...  

A miniaturized assay was set up to test a set of natural products against protein tyrosine phosphatase 1B (PTP1B). By using several read-out and counter assays, berberine and palmatine were identified as PAINS (pan-assay interference compounds) and α-TOS as a novel inhibitor of PTP1B.



2021 ◽  
Vol 18 ◽  
Author(s):  
Sarah Kappler ◽  
Andreas Siebert ◽  
Uli Kazmaier

Introduction: Miuraenamides belong to marine natural compounds with interesting biological properties. Materials and Methods: They initiate polymerization of monomeric actin and therefore show high cytotoxicity by influencing the cytoskeleton. New derivatives of the miuraenamides have been synthesized containing a N-methylated amide bond instead of the more easily hydrolysable ester in the natural products. Results: Incorporation of an aromatic side chain onto the C-terminal amino acid of the tripeptide fragment also led to highly active new miuraenamides. Conclusion: We could show that the ester bond of the natural product miuraenamide can be replaced by an N-methyl amide. The yields in the cyclization step are high and generally much better that with the corresponding esters. On the other hand, the biological activity of the new amide analogs are lower compared to the natural products, but the activity can significantly be increased by incorporation of a p-nitrophenyl group at the C-terminus of the peptide fragment.



1990 ◽  
Vol 10 (10) ◽  
pp. 5071-5076
Author(s):  
C A Hrycyna ◽  
S Clarke

Membrane extracts of sterile Saccharomyces cerevisiae strains containing the a-specific ste14 mutation lack a farnesyl cysteine C-terminal carboxyl methyltransferase activity that is present in wild-type a and alpha cells. Other a-specific sterile strains with ste6 and ste16 mutations also have wild-type levels of the farnesyl cysteine carboxyl methyltransferase activity. This enzyme activity, detected by using a synthetic peptide sequence based on the C-terminus of a ras protein, may be responsible not only for the essential methylation of the farnesyl cysteine residue of a mating factor, but also for the methylation of yeast RAS1 and RAS2 proteins and possibly other polypeptides with similar C-terminal structures. We demonstrate that the farnesylation of the cysteine residue in the peptide is required for the methyltransferase activity, suggesting that methyl esterification follows the lipidation reaction in the cell. To show that the loss of methyltransferase activity is a direct result of the ste14 mutation, we transformed ste14 mutant cells with a plasmid complementing the mating defect of this strain and found that active enzyme was produced. Finally, we demonstrated that a similar transformation of cells possessing the wild-type STE14 gene resulted in sixfold overproduction of the enzyme. Although more complicated possibilities cannot be ruled out, these results suggest that STE14 is a candidate for the structural gene for a methyltransferase involved in the formation of isoprenylated cysteine alpha-methyl ester C-terminal structures.





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