1
|
Kubyshkin V, Rubini M. Proline Analogues. Chem Rev 2024. [PMID: 38941181 DOI: 10.1021/acs.chemrev.4c00007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2024]
Abstract
Within the canonical repertoire of the amino acid involved in protein biogenesis, proline plays a unique role as an amino acid presenting a modified backbone rather than a side-chain. Chemical structures that mimic proline but introduce changes into its specific molecular features are defined as proline analogues. This review article summarizes the existing chemical, physicochemical, and biochemical knowledge about this peculiar family of structures. We group proline analogues from the following compounds: substituted prolines, unsaturated and fused structures, ring size homologues, heterocyclic, e.g., pseudoproline, and bridged proline-resembling structures. We overview (1) the occurrence of proline analogues in nature and their chemical synthesis, (2) physicochemical properties including ring conformation and cis/trans amide isomerization, (3) use in commercial drugs such as nirmatrelvir recently approved against COVID-19, (4) peptide and protein synthesis involving proline analogues, (5) specific opportunities created in peptide engineering, and (6) cases of protein engineering with the analogues. The review aims to provide a summary to anyone interested in using proline analogues in systems ranging from specific biochemical setups to complex biological systems.
Collapse
Affiliation(s)
| | - Marina Rubini
- School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
| |
Collapse
|
2
|
Angera IJ, Wright MM, Del Valle JR. Beyond N-Alkylation: Synthesis, Structure, and Function of N-Amino Peptides. Acc Chem Res 2024; 57:1287-1297. [PMID: 38626119 DOI: 10.1021/acs.accounts.4c00024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/18/2024]
Abstract
The growing list of physiologically important protein-protein interactions (PPIs) has amplified the need for compounds to target topologically complex biomolecular surfaces. In contrast to small molecules, peptide and protein mimics can exhibit three-dimensional shape complementarity across a large area and thus have the potential to significantly expand the "druggable" proteome. Strategies to stabilize canonical protein secondary structures without sacrificing side-chain content are particularly useful in the design of peptide-based chemical probes and therapeutics.Substitution of the backbone amide in peptides represents a subtle chemical modification with profound effects on conformation and stability. Studies focused on N-alkylation have already led to broad-ranging applications in peptidomimetic design. Inspired by nonribosomal peptide natural products harboring amide N-oxidations, we envisioned that main-chain hydrazide and hydroxamate bonds would impose distinct conformational preferences and offer unique opportunities for backbone diversification. This Account describes our exploration of peptide N-amination as a strategy for stabilizing canonical protein folds and for the structure-based design of soluble amyloid mimics.We developed a general synthetic protocol to access N-amino peptides (NAPs) on solid support. In an effort to stabilize β-strand conformation, we designed stitched peptidomimetics featuring covalent tethering of the backbone N-amino substituent to the preceding residue side chain. Using a combination of NMR, X-ray crystallography, and molecular dynamics simulations, we discovered that backbone N-amination alone could significantly stabilize β-hairpin conformation in multiple models of folding. Our studies revealed that the amide NH2 substituent in NAPs participates in cooperative noncovalent interactions that promote β-sheet secondary structure. In contrast to Cα-substituted α-hydrazino acids, we found that N-aminoglycine and its N'-alkylated derivatives instead stabilize polyproline II (PPII) conformation. The reactivity of hydrazides also allows for late-stage peptide macrocyclization, affording novel covalent surrogates of side-chain-backbone H-bonds.The pronounced β-sheet propensity of Cα-substituted α-hydrazino acids prompted us to target amyloidogenic proteins using NAP-based β-strand mimics. Backbone N-amination was found to render aggregation-prone lead sequences soluble and resistant to proteolysis. Inhibitors of Aβ and tau identified through N-amino scanning blocked protein aggregation and the formation of mature fibrils in vitro. We further identified NAP-based single-strand and cross-β tau mimics capable of inhibiting the prion-like cellular seeding activity of recombinant and patient-derived tau fibrils.Our studies establish backbone N-amination as a valuable addition to the peptido- and proteomimetic tool kit. α-Hydrazino acids show particular promise as minimalist β-strand mimics that retain side-chain information. Late-stage derivatization of hydrazides also provides facile entry into libraries of backbone-edited peptides. We anticipate that NAPs will thus find applications in the development of optimally constrained folds and modulators of PPIs.
Collapse
Affiliation(s)
- Isaac J Angera
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Madison M Wright
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Juan R Del Valle
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| |
Collapse
|
3
|
Starnes SK, Del Valle JR. Synthesis, derivatization, and conformational scanning of peptides containing N-Aminoglycine. Methods Enzymol 2024; 698:1-26. [PMID: 38886028 DOI: 10.1016/bs.mie.2024.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
N-alkylated glycine residues are the main constituent of peptoids and peptoid-peptide hybrids that are employed across the biomedical and materials sciences. While the impact of backbone N-alkylation on peptide conformation has been extensively studied, less is known about the effect of N-amination on the secondary structure propensity of glycine. Here, we describe a convenient protocol for the incorporation of N-aminoglycine into host peptides on solid support. Amide-to-hydrazide substitution also affords a nucleophilic handle for further derivatization of the backbone. To demonstrate the utility of late-stage hydrazide modification, we synthesized and evaluated the stability of polyproline II helix and β-hairpin model systems harboring N-aminoglycine derivatives. The described procedures provide facile entry into peptidomimetic libraries for conformational scanning.
Collapse
|
4
|
Nutter M, Stone H, Shipman M, Roesner S. Stereoselective synthesis of ( R)- and ( S)-1,2-diazetidine-3-carboxylic acid derivatives for peptidomimetics. Org Biomol Chem 2024; 22:2974-2977. [PMID: 38533707 DOI: 10.1039/d4ob00278d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
The stereoselective synthesis of both enantiomers of N-protected 1,2-diazetidine-3-carboxylic acid (aAze) from homochiral glycidol is described. Orthogonal protection of this novel cyclic α-hydrazino acid allows for selective functionalisation at either Nγ or Nδ. This novel peptidomimetic building block was incorporated into the pseudotripeptides Gly-γaAze-Ala and Gly-δaAze-Ala.
Collapse
Affiliation(s)
- Matthew Nutter
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.
| | - Henry Stone
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.
| | - Michael Shipman
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.
| | - Stefan Roesner
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.
| |
Collapse
|
5
|
Anwar AF, Cain CF, Garza MJ, Degen D, Ebright RH, Del Valle JR. Stabilizing Pseudouridimycin: Synthesis, RNA Polymerase Inhibitory Activity, and Antibacterial Activity of Dipeptide-Modified Analogues. ChemMedChem 2024; 19:e202300474. [PMID: 37751316 PMCID: PMC10843019 DOI: 10.1002/cmdc.202300474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 09/25/2023] [Accepted: 09/25/2023] [Indexed: 09/28/2023]
Abstract
Pseudouridimycin (PUM) is a microbially produced C-nucleoside dipeptide that selectively targets the nucleotide addition site of bacterial RNA polymerase (RNAP) and that has a lower rate of spontaneous resistance emergence relative to current drugs that target RNAP. Despite its promising biological profile, PUM undergoes relatively rapid decomposition in buffered aqueous solutions. Here, we describe the synthesis, RNAP-inhibitory activity, and antibacterial activity of chemically stabilized analogues of PUM. These analogues feature targeted modifications that mitigate guanidine-mediated hydroxamate bond scission. A subset of analogues in which the central hydroxamate is replaced with amide or hydrazide isosteres retain the antibacterial activity of the natural product.
Collapse
Affiliation(s)
- Avraz F Anwar
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Christopher F Cain
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Michael J Garza
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - David Degen
- Waksman Institute and Department of Chemistry, Rutgers University, Piscataway, NJ, 08854, USA
| | - Richard H Ebright
- Waksman Institute and Department of Chemistry, Rutgers University, Piscataway, NJ, 08854, USA
| | - Juan R Del Valle
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| |
Collapse
|
6
|
Rajewski BH, Wright MM, Gerrein TA, Del Valle JR. N-Aminoglycine and Its Derivatives Stabilize PPII Secondary Structure. Org Lett 2023; 25:4366-4370. [PMID: 37276840 DOI: 10.1021/acs.orglett.3c01502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The identification of unnatural residues that stabilize polyproline type 2 (PPII) folds can aid in the design of peptidomimetics targeting PPII-binding domains. Here, we examine the impact of peptide backbone N-amination on PPII helix stability and find N-aminoglycine (aGly) to be an effective PPII promoter. Further derivatization of an aGly-containing peptide affords N'-alkylated analogues with increased helical propensity. Backbone N-amination of glycine represents a convenient approach to stabilize PPII conformation and allows for the diversity-oriented synthesis of optimally constrained folds.
Collapse
Affiliation(s)
- Benjamin H Rajewski
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Madison M Wright
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Taylor A Gerrein
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Juan R Del Valle
- Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| |
Collapse
|
7
|
Thadem N, Rajesh M, Balaboina H, Das S. Synthesis of bridgehead-azacycles via dual C-N/C-C annulation of α-amino acids, aminals and maleimides. Org Biomol Chem 2022; 20:6368-6383. [PMID: 35861324 DOI: 10.1039/d2ob01117d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of various bridged azacyclic adducts has recently become a reemerging topic due to their bioactive and natural product mimic profiles. Accordingly, herein, we report a method for easy access to succinamide-bridged azacyclic derivatives through the metal-free polarization-controlled dual C-N/C-C annulation of readily available α-amino acids, 2-amino benzaldehydes or pyrrole/indole-2-aldehyde and maleimide substrates. This cascade features a rare dipolarophile-induced diastereo-selective amidative annulation, followed by 3 + 2 cycloaddition as key steps.
Collapse
Affiliation(s)
- Nagender Thadem
- Department of Organic Synthesis & Process Chemistry, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India. .,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Manda Rajesh
- Department of Organic Synthesis & Process Chemistry, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India.
| | - Harikrishna Balaboina
- Department of Organic Synthesis & Process Chemistry, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India.
| | - Saibal Das
- Department of Organic Synthesis & Process Chemistry, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India. .,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| |
Collapse
|
8
|
Del Valle JR, Gerrein TA, Elbatrawi YM. Diastereoselective Synthesis of (3R,5R)-γ-Hydroxypiperazic Acid. Synlett 2021. [DOI: 10.1055/s-0040-1719824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AbstractWe report an asymmetric synthesis of the (3R,5R)-γ-hydroxypiperazic acid (γ-OHPiz) residue encountered in several bioactive nonribosomal peptides. Our strategy relies on a diastereoselective enolate hydroxylation reaction and electrophilic N-amination to provide the acyclic γ-OHPiz precursor. This orthogonally protected α-hydrazino acid intermediate is amenable to late-stage diazinane ring formation following incorporation into a peptide chain. We determined the N-terminal amide rotamer propensity of the γ-OHPiz residue and showed that the γ-OH substituent enhances trans-amide bias relative to piperazic acid.
Collapse
|
9
|
Davern CM, Lowe BD, Rosfi A, Ison EA, Proulx C. Submonomer synthesis of peptoids containing trans-inducing N-imino- and N-alkylamino-glycines. Chem Sci 2021; 12:8401-8410. [PMID: 34221321 PMCID: PMC8221195 DOI: 10.1039/d1sc00717c] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 05/09/2021] [Indexed: 11/21/2022] Open
Abstract
The use of hydrazones as a new type of submonomer in peptoid synthesis is described, giving access to peptoid monomers that are structure-inducing. A wide range of hydrazones were found to readily react with α-bromoamides in routine solid phase peptoid submonomer synthesis. Conditions to promote a one-pot cleavage of the peptoid from the resin and reduction to the corresponding N-alkylamino side chains were also identified, and both the N-imino- and N-alkylamino glycine residues were found to favor the trans-amide bond geometry by NMR, X-ray crystallography, and computational analyses.
Collapse
Affiliation(s)
- Carolynn M Davern
- Department of Chemistry, North Carolina State University Raleigh NC 27695-8204 USA
| | - Brandon D Lowe
- Department of Chemistry, North Carolina State University Raleigh NC 27695-8204 USA
| | - Adam Rosfi
- Department of Chemistry, North Carolina State University Raleigh NC 27695-8204 USA
| | - Elon A Ison
- Department of Chemistry, North Carolina State University Raleigh NC 27695-8204 USA
| | - Caroline Proulx
- Department of Chemistry, North Carolina State University Raleigh NC 27695-8204 USA
| |
Collapse
|
10
|
Rathman BM, Rowe JL, Del Valle JR. Synthesis and conformation of backbone N-aminated peptides. Methods Enzymol 2021; 656:271-294. [PMID: 34325790 DOI: 10.1016/bs.mie.2021.04.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The chemical modification of peptides is a promising approach for the design of protein-protein interaction inhibitors and peptide-based drug candidates. Among several peptidomimetic strategies, substitution of the amide backbone maintains side-chain functionality that may be important for engagement of biological targets. Backbone amide substitution has been largely limited to N-alkylation, which can promote cis amide geometry and disrupt important H-bonding interactions. In contrast, N-amination of peptides induces distinct backbone geometries and maintains H-bond donor capacity. In this chapter we discuss the conformational characteristics of designed N-amino peptides and present a detailed protocol for their synthesis on solid support. The described methods allow for backbone N-amino scanning of biologically active parent sequences.
Collapse
|
11
|
Liu JY, Sun XY, Tang Q, Song JJ, Li XQ, Gong B, Liu R, Lu ZL. An unnatural tripeptide structure containing intramolecular double H-bonds mimics a turn hairpin conformation. Org Biomol Chem 2021; 19:4359-4363. [PMID: 33908557 DOI: 10.1039/d1ob00526j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A series of unnatural tripeptides, each consisting of two aromatic γ-amino acid residues and an ϖ-amino acid residue, are designed to probe their folding into hairpin conformations. The ϖ-amino acid residues, with aliphatic or aromatic spacers of different sizes, serve as the loop of the hairpins. Studies based on one-dimensional (1D) 1H NMR performed at different concentrations, solvent polarity, and temperature, along with 2D-NMR studies, demonstrated that the doubly H-bonded aromatic γ-amino acid residues play important roles in driving these tripeptides into the hairpin conformation. The loop based on 5-aminovaleric acid, which offers a four-carbon (CH2)4 spacer, enhanced the stability of the corresponding hairpin, while loops having a shorter, a longer and a more rigid spacer disfavored the formation of the hairpins. Results from computational studies are in good agreement with the experimental observations. Furthermore, the crystal structure of peptide 1b revealed the expected hairpin conformation in the solid state. This turn motif, which contains H-bonded aromatic γ-amino acid residues as the core unit and an ϖ-amino acid residue serving as the loop, provides a new platform that can be used to obtain a variety of turn conformations by incorporating diverse amino acids into the loops.
Collapse
Affiliation(s)
- Jin-Yu Liu
- Key Laboratory of Radiopharmaceuticals, MOE; College of Chemistry, Beijing Normal University, Xinjiekouwai Street 19, Beijing 100875, China.
| | - Xue-Yi Sun
- Key Laboratory of Radiopharmaceuticals, MOE; College of Chemistry, Beijing Normal University, Xinjiekouwai Street 19, Beijing 100875, China.
| | - Quan Tang
- Key Laboratory of Radiopharmaceuticals, MOE; College of Chemistry, Beijing Normal University, Xinjiekouwai Street 19, Beijing 100875, China.
| | - Jun-Jie Song
- Key Laboratory of Radiopharmaceuticals, MOE; College of Chemistry, Beijing Normal University, Xinjiekouwai Street 19, Beijing 100875, China.
| | - Xiao-Qi Li
- Key Laboratory of Radiopharmaceuticals, MOE; College of Chemistry, Beijing Normal University, Xinjiekouwai Street 19, Beijing 100875, China.
| | - Bing Gong
- Department of Chemistry, The State University of New York at Buffalo, Buffalo, New York 14260, USA
| | - Rui Liu
- Key Laboratory of Radiopharmaceuticals, MOE; College of Chemistry, Beijing Normal University, Xinjiekouwai Street 19, Beijing 100875, China.
| | - Zhong-Lin Lu
- Key Laboratory of Radiopharmaceuticals, MOE; College of Chemistry, Beijing Normal University, Xinjiekouwai Street 19, Beijing 100875, China.
| |
Collapse
|