1
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Synthesis of Tetrapeptides Containing Dehydroalanine, Dehydrophenylalanine and Oxazole as Building Blocks for Construction of Foldamers and Bioinspired Catalysts. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27092611. [PMID: 35565962 PMCID: PMC9102237 DOI: 10.3390/molecules27092611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/14/2022] [Accepted: 04/15/2022] [Indexed: 11/17/2022]
Abstract
The incorporation of dehydroamino acid or fragments of oxazole into peptide chain is accompanied by a distorted three-dimensional structure and additionally enables the introduction of non-typical side-chain substituents. Thus, such compounds could be building blocks for obtaining novel foldamers and/or artificial enzymes (artzymes). In this paper, effective synthetic procedures leading to such building blocks-tetrapeptides containing glycyldehydroalanine, glycyldehydrophenylalanine, and glycyloxazole subunits-are described. Peptides containing serine were used as substrates for their conversion into peptides containing dehydroalanine and aminomethyloxazole-4-carboxylic acid while considering possible requirements for the introduction of these fragments into long-chain peptides at the last steps of synthesis.
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2
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Parker PD, Hou X, Dong VM. Reducing Challenges in Organic Synthesis with Stereoselective Hydrogenation and Tandem Catalysis. J Am Chem Soc 2021; 143:6724-6745. [PMID: 33891819 DOI: 10.1021/jacs.1c00750] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Tandem catalysis enables the rapid construction of complex architectures from simple building blocks. This Perspective shares our interest in combining stereoselective hydrogenation with transformations such as isomerization, oxidation, and epimerization to solve diverse challenges. We highlight the use of tandem hydrogenation for preparing complex natural products from simple prochiral building blocks and present tandem catalysis involving transfer hydrogenation and dynamic kinetic resolution. Finally, we underline recent breakthroughs and opportunities for asymmetric hydrogenation.
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Affiliation(s)
- Patrick D Parker
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Xintong Hou
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Vy M Dong
- Department of Chemistry, University of California, Irvine, California 92697, United States
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3
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Joaquin D, Lee MA, Kastner DW, Singh J, Morrill ST, Damstedt G, Castle SL. Impact of Dehydroamino Acids on the Structure and Stability of Incipient 3 10-Helical Peptides. J Org Chem 2019; 85:1601-1613. [PMID: 31730750 DOI: 10.1021/acs.joc.9b02747] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A comparative study of the impact of small, medium-sized, and bulky α,β-dehydroamino acids (ΔAAs) on the structure and stability of Balaram's incipient 310-helical peptide (1) is reported. Replacement of the N-terminal Aib residue of 1 with a ΔAA afforded peptides 2a-c that maintained the 310-helical shape of 1. In contrast, installation of a ΔAA in place of Aib-3 yielded peptides 3a-c that preferred a β-sheet-like conformation. The impact of the ΔAA on peptide structure was independent of size, with small (ΔAla), medium-sized (Z-ΔAbu), and bulky (ΔVal) ΔAAs exerting similar effects. The proteolytic stabilities of 1 and its analogs were determined by incubation with Pronase. Z-ΔAbu and ΔVal increased the resistance of peptides to proteolysis when incorporated at the 3-position and had negligible impact on stability when placed at the 1-position, whereas ΔAla-containing peptides degraded rapidly regardless of position. Exposure of peptides 2a-c and 3a-c to the reactive thiol cysteamine revealed that ΔAla-containing peptides underwent conjugate addition at room temperature, while Z-ΔAbu- and ΔVal-containing peptides were inert even at elevated temperatures. These results suggest that both bulky and more accessible medium-sized ΔAAs should be valuable tools for bestowing rigidity and proteolytic stability on bioactive peptides.
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Affiliation(s)
- Daniel Joaquin
- Department of Chemistry and Biochemistry , Brigham Young University , Provo , Utah 84602 , United States
| | - Michael A Lee
- Department of Chemistry and Biochemistry , Brigham Young University , Provo , Utah 84602 , United States
| | - David W Kastner
- Department of Chemistry and Biochemistry , Brigham Young University , Provo , Utah 84602 , United States
| | - Jatinder Singh
- Department of Chemistry and Biochemistry , Brigham Young University , Provo , Utah 84602 , United States
| | - Shardon T Morrill
- Department of Chemistry and Biochemistry , Brigham Young University , Provo , Utah 84602 , United States
| | - Gracie Damstedt
- Department of Chemistry and Biochemistry , Brigham Young University , Provo , Utah 84602 , United States
| | - Steven L Castle
- Department of Chemistry and Biochemistry , Brigham Young University , Provo , Utah 84602 , United States
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4
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Jalan A, Kastner DW, Webber KGI, Smith MS, Price JL, Castle SL. Bulky Dehydroamino Acids Enhance Proteolytic Stability and Folding in β-Hairpin Peptides. Org Lett 2017; 19:5190-5193. [PMID: 28910115 PMCID: PMC6085080 DOI: 10.1021/acs.orglett.7b02455] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The bulky dehydroamino acids dehydrovaline (ΔVal) and dehydroethylnorvaline (ΔEnv) can be inserted into the turn regions of β-hairpin peptides without altering their secondary structures. These residues increase proteolytic stability, with ΔVal at the (i + 1) position having the most substantial impact. Additionally, a bulky dehydroamino acid can be paired with a d-amino acid (i.e., d-Pro) to synergistically enhance resistance to proteolysis. A link between proteolytic stability and peptide structure is established by the finding that a stabilized ΔVal-containing β-hairpin is more highly folded than its Asn-containing congener.
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Affiliation(s)
- Ankur Jalan
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, United States
| | - David W. Kastner
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, United States
| | - Kei G. I. Webber
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, United States
| | - Mason S. Smith
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, United States
| | - Joshua L. Price
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, United States
| | - Steven L. Castle
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, 84602, United States
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5
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Le DN, Riedel J, Kozlyuk N, Martin RW, Dong VM. Cyclizing Pentapeptides: Mechanism and Application of Dehydrophenylalanine as a Traceless Turn-Inducer. Org Lett 2016; 19:114-117. [DOI: 10.1021/acs.orglett.6b03308] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Diane N. Le
- Department
of Chemistry, University of California, Irvine, California 92697, United States
| | - Jan Riedel
- Department
of Chemistry, University of California, Irvine, California 92697, United States
| | - Natalia Kozlyuk
- Department
of Chemistry, University of California, Irvine, California 92697, United States
| | - Rachel W. Martin
- Department
of Chemistry, University of California, Irvine, California 92697, United States
- Department
of Molecular Biology and Biochemistry, University of California, Irvine, California 92697, United States
| | - Vy M. Dong
- Department
of Chemistry, University of California, Irvine, California 92697, United States
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6
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Buczek A, Makowski M, Jewgiński M, Latajka R, Kupka T, Broda MA. Toward engineering efficient peptidomimetics. Screening conformational landscape of two modified dehydroaminoacids. Biopolymers 2016; 101:28-40. [PMID: 23606332 DOI: 10.1002/bip.22264] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 04/12/2013] [Indexed: 11/11/2022]
Abstract
Effective peptidomimetics should posses structural rigidity and appropriate interaction pattern leading to potential spatial and electronic matching to the target receptor site. Rational design of such small bioactive molecules could push chemical synthesis and molecular modeling toward faster progress in medicinal chemistry. Conformational properties of N-t-butoxycarbonyl-glycine-(E/Z)-dehydrophenylalanine N',N'-dimethylamides (Boc-Gly-(E/Z)-ΔPhe-NMe2 ) in chloroform were studied by NMR and IR spectroscopy. The experimental findings were supported by extensive calculations at DFT(B3LYP, M06-2X) and MP2 levels of theory and the β-turn tendency for both isomers of the studied dipeptide were determined in vacuum and in solution. The theoretical data and experimental IR results were used as an additional information for the NMR-based determination of the detailed solution conformations of the peptides. The obtained results reveal that N-methylation of C-terminal amide group changes dramatically the conformational properties of studied dehydropeptides. Theoretical conformational analysis reveals that the tendency to adopt β-turn conformations is much weaker for the N-methylated Z isomer (Boc-Gly-(Z)-ΔPhe-NMe2 ), both in vacuum and in polar environment. On the contrary, N-methylated E isomer (Boc-Gly-(E)-ΔPhe-NMe2 ) can easily adopt β-turn conformation, but the backbone torsion angles (φ1, ψ1, φ2, ψ2) are off the limits for common β-turn types.
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Affiliation(s)
- Aneta Buczek
- Department of Physical Chemistry and Molecular Modeling, Faculty of Chemistry, University of Opole, Oleska 48, 45-052, Opole, Poland
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7
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Kaminský J, Jensen F. Conformational Interconversions of Amino Acid Derivatives. J Chem Theory Comput 2016; 12:694-705. [PMID: 26691979 DOI: 10.1021/acs.jctc.5b00911] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Exhaustive conformational interconversions including transition structure analyses of N-acetyl-l-glycine-N-methylamide as well as its alanine, serine, and cysteine analogues have been investigated at the MP2/6-31G** level, yielding a total of 142 transition states. Improved estimates of relative energies were obtained by separately extrapolating the Hartree-Fock and MP2 energies to the basis set limit and adding the difference between CCSD(T) and MP2 results with the cc-pVDZ basis set to the extrapolated MP2 results. The performance of eight empirical force fields (AMBER94, AMBER14SB, MM2, MM3, MMFFs, CHARMM22_CMAP, OPLS_2005, and AMOEBAPRO13) in reproducing ab initio energies of transition states was tested. Our results indicate that commonly used class I force fields employing a fixed partial charge model for the electrostatic interaction provide mean errors in the ∼10 kJ/mol range for energies of conformational transition states for amino acid conformers. Modern reparametrized versions, such as CHARMM22_CMAP, and polarizable force fields, such as AMOEBAPRO13, have slightly lower mean errors, but maximal errors are still in the 35 kJ/mol range. There are differences between the force fields in their ability for reproducing conformational transitions classified according to backbone/side-chain or regions in the Ramachandran angles, but the data set is likely too small to draw any general conclusions. Errors in conformational interconversion barriers by ∼10 kJ/mol suggest that the commonly used force field may bias certain types of transitions by several orders of magnitude in rate and thus lead to incorrect dynamics in simulations. It is therefore suggested that information for conformational transition states should be included in parametrizations of new force fields.
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Affiliation(s)
- Jakub Kaminský
- Institute of Organic Chemistry and Biochemistry, Flemingovo nám. 2, 166 10 Prague, Czech Republic
| | - Frank Jensen
- Department of Chemistry, Aarhus University , Langelandsgade 140, DK-8000 Aarhus C, Denmark
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8
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Jiang J, Luo S, Castle SL. Solid-phase synthesis of peptides containing bulky dehydroamino acids. Tetrahedron Lett 2015. [DOI: 10.1016/j.tetlet.2014.12.097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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9
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Crisma M, De Zotti M, Formaggio F, Peggion C, Moretto A, Toniolo C. Handedness preference and switching of peptide helices. Part II: Helices based on noncodedα-amino acids. J Pept Sci 2015; 21:148-77. [DOI: 10.1002/psc.2743] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 12/19/2014] [Accepted: 12/19/2014] [Indexed: 12/27/2022]
Affiliation(s)
| | - Marta De Zotti
- Department of Chemistry; University of Padova; Padova Italy
| | - Fernando Formaggio
- ICB; Padova Unit; CNR Padova Italy
- Department of Chemistry; University of Padova; Padova Italy
| | | | - Alessandro Moretto
- ICB; Padova Unit; CNR Padova Italy
- Department of Chemistry; University of Padova; Padova Italy
| | - Claudio Toniolo
- ICB; Padova Unit; CNR Padova Italy
- Department of Chemistry; University of Padova; Padova Italy
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10
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11
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Siodłak D, Macedowska-Capiga A, Broda MA, Kozioł AE, Lis T. The cis-trans isomerization of N-methyl-α,β-dehydroamino acids. Biopolymers 2014. [PMID: 23203691 DOI: 10.1002/bip.22082] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Dehydroamino acids with the methylated N-terminal peptide group occur in natural small cyclic peptides. The structural analysis was used to investigate the cis-trans isomerization of the N-terminal tertiary amide group of diamides: Ac-(Z)-Δ(Me)Abu-NHMe (1), Ac-(Z)-Δ(Me)Phe-NHMe (2), Ac-(E)-Δ(Me)Phe-NHMe (3), Ac-Δ(Me)Ala-NHMe (4), and Ac-(Me)Ala-NHMe (5). The compounds were analyzed in the solid state by an X-ray crystallography (1-3), and in the solution by FTIR (MeCN and CHCl(3) ) and NMR (DMSO-d6 and CDCl(3) ) methods (1-5). In the solid state, the studied compounds adopt the cis configuration of N-terminal amide. In solution, this configuration also prevails for the dehydroamino acids 1-4, in contrast to the saturated analog 5. The results indicate that N-methyldehydroamino acids present a promising tool to induce the cis configuration of the amide bond.
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Affiliation(s)
- Dawid Siodłak
- Faculty of Chemistry, University of Opole, Oleska 48, Opole 45-052, Poland.
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12
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Buczek A, Broda MA. DFT study of N–H···O hydrogen bond between model dehydropeptides and water molecule. Mol Phys 2013. [DOI: 10.1080/00268976.2013.847979] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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13
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Malek K, Makowski M, Królikowska A, Bukowska J. Comparative studies on IR, Raman, and surface enhanced Raman scattering spectroscopy of dipeptides containing ΔAla and ΔPhe. J Phys Chem B 2012; 116:1414-25. [PMID: 22208201 DOI: 10.1021/jp208586j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Three dipeptides containing dehydroresidues (ΔAla, Δ((Z))Phe, and Δ((E))Phe) were examined by IR, Raman, and surface-enhanced Raman techniques for the first time. The effect of the size and isomer type of the β-substituent in the dehydroresidue on the conformational structure of the peptide was evaluated by using the analysis of IR and Raman bands. Additionally, SERS spectroscopy provided insight into the adsorption mechanism of these species on the metal surface. SERS spectra were recorded at alkaline pH on the silver sol using visible light excitation. The dehydroresidues studied here strongly influenced the SERS profile of the peptides. The most pronounced SERS signal for all dipeptides was assigned to the symmetric stretching vibration of the carboxylate ions. This indicates that the dehydropeptides studied here primarily adsorb via the deprotonated carboxylic group. Additionally, the enhanced SERS bands in the range 1550-1650 cm(-1) show differences in contribution of the dehydroresidue to the adsorption mechanism of the studied peptides.
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Affiliation(s)
- Kamilla Malek
- Faculty of Chemistry, Jagiellonian Chemistry, Ingardena 3, 30-060 Krakow, Poland.
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14
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Buczek AM, Ptak T, Kupka T, Broda MA. Experimental and theoretical NMR and IR studies of the side-chain orientation effects on the backbone conformation of dehydrophenylalanine residue. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2011; 49:343-349. [PMID: 21506144 DOI: 10.1002/mrc.2753] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 02/09/2011] [Accepted: 02/16/2011] [Indexed: 05/30/2023]
Abstract
Conformation of N-acetyl-(E)-dehydrophenylalanine N', N'-dimethylamide (Ac-(E)-ΔPhe-NMe(2)) in solution, a member of (E)-α, β-dehydroamino acids, was studied by NMR and infrared spectroscopy and the results were compared with those obtained for (Z) isomer. To support the spectroscopic interpretation, the Φ, Ψ potential energy surfaces were calculated at the MP2/6-31 + G(d,p) level of theory in chloroform solution modeled by the self-consistent reaction field-polarizable continuum model method. All minima were fully optimized by the MP2 method and their relative stabilities were analyzed in terms of π-conjugation, internal H-bonds and dipole interactions between carbonyl groups. The obtained NMR spectral features were compared with theoretical nuclear magnetic shieldings, calculated using Gauge Independent Atomic Orbitals (GIAO) approach and rescaled to theoretical chemical shifts using benzene as reference. The calculated indirect nuclear spin-spin coupling constants were compared with available experimental parameters.
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Affiliation(s)
- Aneta M Buczek
- Faculty of Chemistry, University of Opole, 48, Oleska Street, 45-052 Opole, Poland
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15
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Bouteiller Y, Poully JC, Grégoire G. Evaluation of polarizable continuum model for the prediction of vibrational frequencies of biomimetic molecules in solution. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2011.03.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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16
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Buczek A, Siodłak D, Bujak M, Broda MA. Effects of side-chain orientation on the backbone conformation of the dehydrophenylalanine residue. Theoretical and X-ray study. J Phys Chem B 2011; 115:4295-306. [PMID: 21443240 DOI: 10.1021/jp200949t] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two E isomers of α,β-dehydro-phenylalanine, Ac-(E)-ΔPhe-NHMe (1a) and Ac-(E)-ΔPhe-NMe(2) (2a), have been synthesized and their low temperature structures determined by single-crystal X-ray diffraction. A systematic theoretical analysis was performed on these molecules and their Z isomers (1b and 2b). The ϕ,ψ potential energy surfaces were calculated at the MP2/6-31+G(d,p) and B3LYP/6-31+G(d,p) levels in the gas phase and at the B3LYP/6-31+G(d,p) level in the chloroform and water solutions with the SCRF-PCM method. All minima were fully optimized by the MP2 and DFT methods, and their relative stabilities were analyzed in terms of π-conjugation, internal H-bonds, and dipole-dipole interactions between carbonyl groups. The results indicate that all the studied compounds can adopt the conformation H (ϕ, ψ ≈ ±40°, ∓120°) which is atypical for standard amino acids residues. A different arrangement of the side chain in the E and Z isomers causes them to have different conformational preferences. In the presence of a polar solvent both Z isomers of ΔPhe (1b and 2b) are found to adopt the 3(10)-helical conformation (left- and right-handed are equally likely). On the other hand, this conformation is not accessible or highly energetic for E isomers of ΔPhe (1a and 2a). Those isomers have an intrinsic inclination to have an extended conformation. The conformational space of the Z isomers is much more restricted than that of the E derivative both in the gas phase and in solution. In the gas phase the E isomers of ΔPhe have lower energies than the Z ones, but in the aqueous solution the energy order is reversed.
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Affiliation(s)
- Aneta Buczek
- Faculty of Chemistry, University of Opole, Poland
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17
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Siodlak D, Macedowska-Capiga A, Ejsmont K, Zaleski J, Rzeszotarska B. The conformation cis of N-acetyl-N-methyl-α,β-dehydroalanine N′-methylamide and saturated analogues. ACTA ACUST UNITED AC 2009. [DOI: 10.1524/zkri.2007.222.6.297] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A series of three homologous amino acids derivatives: N-acetyl-N-methyl-α,β–dehydroalanine N′-methylamide (1), N-acetyl-N-methyl-L-alanine N′-methylamide (2), and N-acetyl-N-methyl-DL-alanine N′-methylamide have been synthesised. The racemic species undergoes spontaneous separation into L and D-enantiomers. From these two chiral forms, the structure of L-enantiomer (3) was analysed. The molecules of 1 – 3 adopt the cis arrangement of the N-terminal amide bond. The molecular conformations are similar for 1 (φ, ψ = 94.6(1)°, −1.7(1)°) and 3 (φ, ψ = 111.5(1)°, −23.8(1)°), and also 2 (φ, ψ = −114.8(2)°, 29.5(2)°), if inversion through the chiral C2 carbon is considered. They are stabilised by intramolecular N—H…N hydrogen bond. In the case of 1, the π—electron conjugation resulting from the planar arrangement of the C2—C21 double bond and C-terminal amide group is another stabilising force of this conformation. Thus, the N-methyldehydroalanine residue should promotes trans-cis isomerisation to a greater extend than the saturated analogue. The compounds 1 – 3 reveal similar associative pattern and form centrosymmetric dimers linked by the intermolecular N—H…O hydrogen bonds.
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18
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Aydillo C, Avenoza A, Busto JH, Jiménez-Osés G, Peregrina JM, Zurbano MM. α-Alkylation versus retro-O-Michael/γ-alkylation of bicyclic N,O-acetals: an entry to α-methylthreonine. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.tetasy.2008.11.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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19
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Kaminský J, Jensen F. Force Field Modeling of Amino Acid Conformational Energies. J Chem Theory Comput 2007; 3:1774-88. [DOI: 10.1021/ct700082f] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jakub Kaminský
- Department of Physics and Chemistry, University of Southern Denmark, DK-5230 Odense, Denmark, and Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 166 10 Prague, Czech Republic
| | - Frank Jensen
- Department of Physics and Chemistry, University of Southern Denmark, DK-5230 Odense, Denmark, and Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 166 10 Prague, Czech Republic
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20
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Broda MA, Ciszak EM, Koziol AE, Pietrzynski G, Rzeszotarska B. Conformational investigation of α,β-dehydropeptides. XVI. β-turn tendency in Ac-Pro-ΔXaa-NHMe: crystallographic and theoretical studies. J Pept Sci 2006; 12:538-49. [PMID: 16733828 DOI: 10.1002/psc.763] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The crystal structures of two diastereomeric alpha,beta-dehydrobutyrine peptides Ac-Pro-(Z)-DeltaAbu-NHMe (I) and Ac-Pro-(E)-DeltaAbu-NHMe (II) have been determined. Both dehydropeptides adopt betaI-turn conformation characterized by the pairs of (phi(i+1), psi(i+1)) and (phi(i+2), psi(i+2)) angles as -66, -19, -97, 11 degrees for I and -59, -27, -119, 29 degrees for II. In each peptide, the betaI turn is stabilized by (i + 3) --> i intramolecular hydrogen bonds with N...O distance of 3.12 A for I and 2.93 A for II. These structures have been compared to the crystal structures of homologous peptides Ac-Pro-DeltaVal-NHMe and Ac-Pro-DeltaAla-NHMe. Theoretical analyses by DFT/B3LYP/6-31 + G** method of conformers formed by these four peptides and by the saturated peptide Ac-Pro-Ala-NHMe revealed that peptides with a (Z) substituent at the C(beta) (i+2) atom of dehydroamino acid, i.e. Ac-Pro-DeltaVal-NHMe and Ac-Pro-(Z)-DeltaAbu-NHMe, predominantly form beta turns, both in vacuo and in polar environment. The tendency to adopt beta-turn conformation is much weaker for the peptides lacking the (Z) substituent, Ac-Pro-(E)-DeltaAbu-NHMe and Ac-Pro-DeltaAla-NHMe. The latter adopts a semi-extended or an extended conformation in every polar environment, including a weakly polar solvent. The saturated peptide Ac-Pro-Ala-NHMe in vacuo prefers a beta-turn conformation, but in polar environment the differences between various conformers are small. The role of pi-electron correlation and intramolecular hydrogen bonds interaction in stabilizing the hairpin structures are discussed.
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Affiliation(s)
- Malgorzata A Broda
- Institute of Chemistry, University of Opole, Olesja Street 48, 45-052 Opole, Poland.
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