scholarly journals Total synthesis and biological characterization of SR-A3, a ternatin-related eEF1A inhibitor with enhanced cellular residence time

2020 ◽  
Author(s):  
Hao-Yuan Wang ◽  
Keely Oltion ◽  
Amjad Ayad Qatran Al-Khdhairawi ◽  
Jean-Frédéric F. Weber ◽  
Jack Taunton
Keyword(s):  
Residence Time ◽  
Cyclic Peptides ◽  
Viral Infections ◽  
Cyclic Peptide ◽  
Elongation Factor ◽  
Cancer Cell Proliferation ◽  
Duration Of Action ◽  
Eukaryotic Elongation Factor ◽  
Elongation Phase

AbstractTernatin and related cyclic peptides inhibit the elongation phase of protein synthesis by targeting the eukaryotic elongation factor-1α (eEF1A), a potential therapeutic vulnerability in cancer and viral infections. The cyclic peptide natural product “A3” appears to be related to ternatin, but its complete structure is unknown and only 4 of its 11 stereocenters have been assigned. Hence, A3 could be any one of 128 possible stereoisomers. Guided by the stereochemistry of ternatin and more potent structural variants, we synthesized two A3 epimers, “SR-A3” and “SS-A3”. We found that synthetic SR-A3 is indistinguishable from naturally derived A3 and potently inhibits cancer cell proliferation. Relative to SS-A3 and previously characterized ternatin variants, SR-A3 exhibits a dramatically enhanced duration of action. This increase in cellular residence time is conferred, stereospecifically, by a single β-hydroxy group attached to N-methyl leucine. SR-A3 thus exemplifies a mechanism for enhancing the pharmacological potency of cyclic peptide natural products via side-chain hydroxylation.

scholarly journals Ternatin and improved synthetic variants kill cancer cells by targeting the elongation factor-1A ternary complex

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Jordan D Carelli ◽  
Steven G Sethofer ◽  
Geoffrey A Smith ◽  
Howard R Miller ◽  
Jillian L Simard ◽  
...  
Keyword(s):  
Natural Products ◽  
Cancer Cells ◽  
Cyclic Peptides ◽  
Ternary Complex ◽  
Cyclic Peptide ◽  
Hot Spot ◽  
Elongation Factor ◽  
Hydrophobic Surface ◽  
Eukaryotic Elongation Factor ◽  
Domain Iii

Cyclic peptide natural products have evolved to exploit diverse protein targets, many of which control essential cellular processes. Inspired by a series of cyclic peptides with partially elucidated structures, we designed synthetic variants of ternatin, a cytotoxic and anti-adipogenic natural product whose molecular mode of action was unknown. The new ternatin variants are cytotoxic toward cancer cells, with up to 500-fold greater potency than ternatin itself. Using a ternatin photo-affinity probe, we identify the translation elongation factor-1A ternary complex (eEF1A·GTP·aminoacyl-tRNA) as a specific target and demonstrate competitive binding by the unrelated natural products, didemnin and cytotrienin. Mutations in domain III of eEF1A prevent ternatin binding and confer resistance to its cytotoxic effects, implicating the adjacent hydrophobic surface as a functional hot spot for eEF1A modulation. We conclude that the eukaryotic elongation factor-1A and its ternary complex with GTP and aminoacyl-tRNA are common targets for the evolution of cytotoxic natural products.

A Target-Based Method for Designing Heterochiral Cyclic Peptide Binders: De Novo Inhibitors of the PD-1/PD-L1 Interaction

2020 ◽  
Author(s):  
Salvador Guardiola ◽  
Monica Varese ◽  
Xavier Roig ◽  
Jesús Garcia ◽  
Ernest Giralt
Keyword(s):  
Protein Interactions ◽  
Cyclic Peptides ◽  
General Framework ◽  
Large Scale ◽  
Cyclic Peptide ◽  
De Novo ◽  
Inhibitory Effect ◽  
Original Text ◽  
Retraction Notice ◽  
Pharmaceutical Properties

<p>NOTE: This preprint has been retracted by consensus from all authors. See the retraction notice in place above; the original text can be found under "Version 1", accessible from the version selector above.</p><p><br></p><p>------------------------------------------------------------------------</p><p><br></p><p>Peptides, together with antibodies, are among the most potent biochemical tools to modulate challenging protein-protein interactions. However, current structure-based methods are largely limited to natural peptides and are not suitable for designing target-specific binders with improved pharmaceutical properties, such as macrocyclic peptides. Here we report a general framework that leverages the computational power of Rosetta for large-scale backbone sampling and energy scoring, followed by side-chain composition, to design heterochiral cyclic peptides that bind to a protein surface of interest. To showcase the applicability of our approach, we identified two peptides (PD-<i>i</i>3 and PD-<i>i</i>6) that target PD-1, a key immune checkpoint, and work as protein ligand decoys. A comprehensive biophysical evaluation confirmed their binding mechanism to PD-1 and their inhibitory effect on the PD-1/PD-L1 interaction. Finally, elucidation of their solution structures by NMR served as validation of our <i>de novo </i>design approach. We anticipate that our results will provide a general framework for designing target-specific drug-like peptides.<i></i></p>

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