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Banaś K, Lenartowicz P, Staś M, Dziuk B, Siodłak D. Insight into the Structure of Victorin, the Host-Selective Toxin from the Oat Pathogen Cochliobolus victoriae. Studies of the Unique Dehydroamino Acid β-Chlorodehydroalanine. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023. [PMID: 37486973 PMCID: PMC10401702 DOI: 10.1021/acs.jafc.3c01387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
Victorins, a family of peptide toxins, produced by the fungal pathogen Cochliobolus victoriae and responsible for disease of some oat varieties, contain a β-chlorodehydroalanine residue, ΔAla(βCl). To determine the conformational properties of this unique dehydroamino acid, a series of model compounds was studied using X-ray, NMR, and FT-IR methods, supported by theoretical calculations. The ΔAla(βCl) geometrical isomers differ in conformational profile. The isomer Z prefers the helical conformation α (φ, ψ = -61°, -24°), PPII type conformation β (φ, ψ = -47°, 136°), and semiextended conformation β2 (φ, ψ = -116°, 9°) in weakly and more polar solutions. The isomer E prefers mainly the extended conformation C5 (φ, ψ = -177°, 160°), but with an increase of the environment polarity also conformations β (φ, ψ = -44°, 132°) and α (φ, ψ = -53°, -39°). In the most stable conformations the N-H···Cl hydrogen bond (5γ) occurs, created between the chlorine atom of the side chain and the N-H donor of the flanking amide group. The method of synthesis of the β-chlorodehydroalanine residue is proposed, by chlorination of dehydroalanine and then the photoisomerization from the isomer Z to E. The presented results indicate that the assignment of the geometrical isomer of the ΔAla(βCl) residue in naturally occurring victorins still remains an open question, despite being crucial for biological activity.
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Affiliation(s)
- Karolina Banaś
- Faculty of Chemistry, University of Opole, Oleska 48, 45-052 Opole, Poland
| | - Paweł Lenartowicz
- Faculty of Chemistry, University of Opole, Oleska 48, 45-052 Opole, Poland
| | - Monika Staś
- Faculty of Chemistry, University of Opole, Oleska 48, 45-052 Opole, Poland
| | - Błażej Dziuk
- Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
- Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, Wroclaw 50-383, Poland
| | - Dawid Siodłak
- Faculty of Chemistry, University of Opole, Oleska 48, 45-052 Opole, Poland
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Staś M, Broda MA, Siodłak D. Thiazole-amino acids: influence of thiazole ring on conformational properties of amino acid residues. Amino Acids 2021; 53:673-686. [PMID: 33837859 PMCID: PMC8128816 DOI: 10.1007/s00726-021-02974-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 03/29/2021] [Indexed: 12/29/2022]
Abstract
Post-translational modified thiazole-amino acid (Xaa-Tzl) residues have been found in macrocyclic peptides (e.g., thiopeptides and cyanobactins), which mostly inhibit protein synthesis in Gram + bacteria. Conformational study of the series of model compounds containing this structural motif with alanine, dehydroalanine, dehydrobutyrine and dehydrophenylalanine were performed using DFT method in various environments. The solid-state crystal structure conformations of thiazole-amino acid residues retrieved from the Cambridge Structural Database were also analysed. The studied structural units tend to adopt the unique semi-extended β2 conformation; which is stabilised mainly by N-H⋯NTzl hydrogen bond, and for dehydroamino acids also by π-electron conjugation. The conformational preferences of amino acids with a thiazole ring were compared with oxazole analogues and the role of the sulfur atom in stabilising the conformations of studied peptides was discussed.
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Affiliation(s)
- Monika Staś
- Faculty of Chemistry, University of Opole, 45-052, Opole, Poland.
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Science, Flemingovo Náměstí 2, 166 10, Praha 6, Czech Republic.
| | | | - Dawid Siodłak
- Faculty of Chemistry, University of Opole, 45-052, Opole, Poland.
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Kusakiewicz-Dawid A, Porada M, Ochędzan-Siodłak W, Broda MA, Bujak M, Siodłak D. Pyrazole amino acids: hydrogen bonding directed conformations of 3-amino-1H-pyrazole-5-carboxylic acid residue. J Pept Sci 2017; 23:716-726. [PMID: 28608410 DOI: 10.1002/psc.3018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 05/24/2017] [Accepted: 05/25/2017] [Indexed: 11/06/2022]
Abstract
A series of model compounds containing 3-amino-1H-pyrazole-5-carboxylic acid residue with N-terminal amide/urethane and C-terminal amide/hydrazide/ester groups were investigated by using NMR, Fourier transform infrared, and single-crystal X-ray diffraction methods, additionally supported by theoretical calculations. The studies demonstrate that the most preferred is the extended conformation with torsion angles ϕ and ψ close to ±180°. The studied 1H-pyrazole with N-terminal amide/urethane and C-terminal amide/hydrazide groups solely adopts this energetically favored conformation confirming rigidity of that structural motif. However, when the C-terminal ester group is present, the second conformation with torsion angles ϕ and ψ close to ±180° and 0°, respectively, is accessible. The conformational equilibrium is observed in NMR and Fourier transform infrared studies in solution in polar environment as well as in the crystal structures of other related compounds. The observed conformational preferences are clearly related to the presence of intramolecular interactions formed within the studied residue. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.
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Affiliation(s)
| | - Monika Porada
- Faculty of Chemistry, University of Opole, Oleska 48, 45-052, Opole, Poland
| | | | - Małgorzata A Broda
- Faculty of Chemistry, University of Opole, Oleska 48, 45-052, Opole, Poland
| | - Maciej Bujak
- Faculty of Chemistry, University of Opole, Oleska 48, 45-052, Opole, Poland
| | - Dawid Siodłak
- Faculty of Chemistry, University of Opole, Oleska 48, 45-052, Opole, Poland
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Staś M, Bujak M, Broda MA, Siodłak D. Conformational preferences and synthesis of isomers Z and E of oxazole-dehydrophenylalanine. Biopolymers 2017; 106:283-94. [PMID: 27061820 DOI: 10.1002/bip.22852] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 03/30/2016] [Accepted: 04/05/2016] [Indexed: 12/17/2022]
Abstract
Dehydrophenylalanine, ΔPhe, is the most commonly studied α,β-dehydroamino acid. In nature, further modifications of the α,β-dehydroamino acids were found, for example, replacement of the C-terminal amide group by oxazole ring. The conformational properties of oxazole-dehydrophenylalanine residue (ΔPhe-Ozl), both isomers Z and E, were investigated. To determine all possible conformations, theoretical calculations were performed using Ac-(Z/E)-ΔPhe-Ozl(4-Me) model compounds at M06-2X/6-31++G(d,p) level of theory. Ac-(Z/E)-ΔPhe-Ozl-4-COOEt compounds were synthesized and the conformational preferences of each isomer, Z and E, were investigated using FTIR and NMR-NOE in solutions of increasing polarity (CHCl3 , DMSO-d6). The solid-state low-temperature structures of Ac-(Z)-ΔPhe-Ozl-4-COOEt and its intermediate analog Ac-(Z)-ΔPhe-Ozn(4-OH)-4-COOEt were also determined. In a weakly polar environment, the ΔPhe-Ozl residue has a tendency to adopt the conformation β2 with the calculated φ and ψ angles of -127° and 0° for the isomer Z and -170° and 26° for the isomer E. The increase of environment polarity favors the helical conformation α and the beta-turn like conformation β, but the conformation β2 seems to be still accessible. The (E)-ΔPhe-Ozl residue can be obtained from the isomer Z in photoisomerization reaction. However, hydroxyl-oxazoline-dehydrophenylalanine ΔPhe-Ozn(4-OH) decomposes in such conditions. Alternatively, (E)-ΔPhe-NH2 can be applied as a substrate in the Hantzsch reaction. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 283-294, 2016.
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Affiliation(s)
- Monika Staś
- Faculty of Chemistry, University of Opole, Oleska 48, Opole, 45-052, Poland
| | - Maciej Bujak
- Faculty of Chemistry, University of Opole, Oleska 48, Opole, 45-052, Poland
| | - Małgorzata A Broda
- Faculty of Chemistry, University of Opole, Oleska 48, Opole, 45-052, Poland
| | - Dawid Siodłak
- Faculty of Chemistry, University of Opole, Oleska 48, Opole, 45-052, Poland
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Bartoccini F, Cannas DM, Fini F, Piersanti G. Palladium(II)-Catalyzed Cross-Dehydrogenative Coupling (CDC) of N-Phthaloyl Dehydroalanine Esters with Simple Arenes: Stereoselective Synthesis of Z-Dehydrophenylalanine Derivatives. Org Lett 2016; 18:2762-5. [PMID: 27206072 DOI: 10.1021/acs.orglett.6b01255] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pd(II)-catalyzed cross-dehydrogenative coupling (CDC) of methyl N-phthaloyl dehydroalanine esters with simple aromatic hydrocarbons is reported. The reaction, which involves the cleavage of two sp(2) C-H bonds followed by C-C bond formation, stereoselectively generates highly valuable Z-dehydrophenylalanine skeletons in a practical, versatile, and atom economical manner. In addition, a perfluorinated product was expediently converted into important nonproteinogenic amino acid building blocks through copper-catalyzed conjugate additions of boron, silicon, and hydride moieties.
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Affiliation(s)
- Francesca Bartoccini
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo" , P.zza Rinascimento 6, 61029 Urbino (PU), Italy
| | - Diego Maria Cannas
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo" , P.zza Rinascimento 6, 61029 Urbino (PU), Italy
| | - Francesco Fini
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo" , P.zza Rinascimento 6, 61029 Urbino (PU), Italy
| | - Giovanni Piersanti
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo" , P.zza Rinascimento 6, 61029 Urbino (PU), Italy
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Peggion C, Moretto A, Formaggio F, Crisma M, Toniolo C. Multiple, consecutive, fully-extended 2.0₅-helix peptide conformation. Biopolymers 2016; 100:621-36. [PMID: 23893391 DOI: 10.1002/bip.22267] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 04/16/2013] [Accepted: 04/19/2013] [Indexed: 02/01/2023]
Abstract
The peptide 2.0(5)-helix does exist. It has been experimentally authenticated both in the crystalline state (by X-ray diffraction) and in solution (by several spectroscopic techniques). It is the most common conformation for C(α)-tetrasubstituted α-amino acids with at least two atoms in each side chain, provided that cyclization on the C(α)-atom is absent. X-Ray diffraction has allowed a detailed description of its geometrical and three-dimensional (3D)-structural features. The infrared absorption and the nuclear magnetic resonance parameters characteristics of this multiple, consecutive, fully-extended structure have been described. Conformational energy calculations are in agreement with the experimental findings. As the contribution per amino acid residue to the length of this helix is the longest possible, its exploitation as a molecular spacer is quite promising. However, it is a rather fragile 3D-structure and particularly sensitive to solvent polarity. Interestingly, in such a case, it may reversibly convert to the much shorter 3(10)-helix, thus generating an attractive molecular spring.
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Affiliation(s)
- Cristina Peggion
- Institute of Biomolecular Chemistry, CNR, Padova Unit, Department of Chemistry, University of Padova, 35131, Padova, Italy
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Siodłak D, Staś M, Broda MA, Bujak M, Lis T. Conformational properties of oxazole-amino acids: effect of the intramolecular N-H···N hydrogen bond. J Phys Chem B 2014; 118:2340-50. [PMID: 24528177 DOI: 10.1021/jp4121673] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Oxazole ring occurs in numerous natural peptides, but conformational properties of the amino acid residue containing the oxazole ring in place of the C-terminal amide bond are poorly recognized. A series of model compounds constituted by the oxazole-amino acids occurring in nature, that is, oxazole-alanine (L-Ala-Ozl), oxazole-dehydroalanine (ΔAla-Ozl), and oxazole-dehydrobutyrine ((Z)-ΔAbu-Ozl), was investigated using theoretical calculations supported by FTIR and NMR spectra and single-crystal X-ray diffraction. It was found that the main feature of the studied oxazole-amino acids is the stable conformation β2 with the torsion angles φ and ψ of -150°, -10° for L-Ala-Ozl, -180°, 0° for ΔAla-Ozl, and -120°, 0° for (Z)-ΔAbu-Ozl, respectively. The conformation β2 is stabilized by the intramolecular N-H···N hydrogen bond and predominates in the low polar environment. In the case of the oxazole-dehydroamino acids, the π-electron conjugation that is spread on the oxazole ring and C(α)═C(β) double bond is an additional stabilizing interaction. The tendency to adopt the conformation β2 clearly decreases with increasing the polarity of environment, but still the oxazole-dehydroamino acids are considered to be more rigid and resistant to conformational changes.
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Affiliation(s)
- Dawid Siodłak
- Faculty of Chemistry, University of Opole , Oleska 48, 45-052 Opole, Poland
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Siodłak D, Bujak M, Staś M. Intra- and intermolecular forces dependent main chain conformations of esters of α,β-dehydroamino acids. J Mol Struct 2013. [DOI: 10.1016/j.molstruc.2013.04.078] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Stergiopoulos I, Collemare J, Mehrabi R, De Wit PJGM. Phytotoxic secondary metabolites and peptides produced by plant pathogenic Dothideomycete fungi. FEMS Microbiol Rev 2012; 37:67-93. [PMID: 22931103 DOI: 10.1111/j.1574-6976.2012.00349.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/01/2012] [Accepted: 07/19/2012] [Indexed: 01/25/2023] Open
Abstract
Many necrotrophic plant pathogenic fungi belonging to the class of Dothideomycetes produce phytotoxic metabolites and peptides that are usually required for pathogenicity. Phytotoxins that affect a broad range of plant species are known as non-host-specific toxins (non-HSTs), whereas HSTs affect only a particular plant species or more often genotypes of that species. For pathogens producing HSTs, pathogenicity and host specificity are largely defined by the ability to produce the toxin, while plant susceptibility is dependent on the presence of the toxin target. Non-HSTs are not the main determinants of pathogenicity but contribute to virulence of the producing pathogen. Dothideomycetes are remarkable for the production of toxins, particularly HSTs because they are the only fungal species known so far to produce them. The synthesis, regulation, and mechanisms of action of the most important HSTs and non-HSTs will be discussed. Studies on the mode of action of HSTs have highlighted the induction of programed cell death (PCD) as an important mechanism. We discuss HST-induced PCD and the plant hypersensitive response upon recognition of avirulence factors that share common pathways. In this respect, although nucleotide-binding-site-leucine-rich repeat types of resistance proteins mediate resistance against biotrophs, they can also contribute to susceptibility toward necrotrophs.
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