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Hegde RP, Aravinda S, Rai R, Kaul R, Vijayalakshmi S, Rao RB, Shamala N, Balaram P. Conformation of di-n-propylglycine residues (Dpg) in peptides: crystal structures of a type I′β-turn forming tetrapeptide and an α-helical tetradecapeptide. J Pept Sci 2007; 14:648-59. [DOI: 10.1002/psc.962] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Vogt H, Bräse S. Recent approaches towards the asymmetric synthesis of α,α-disubstituted α-amino acids. Org Biomol Chem 2007; 5:406-30. [PMID: 17252120 DOI: 10.1039/b611091f] [Citation(s) in RCA: 321] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The class of alpha,alpha-disubstituted alpha-amino acids has gained considerable attention in the past decades and continues doing so. The ongoing interest in biological and chemical properties of the substance class has inspired the development of many new methodologies for their asymmetric construction, which have not found their way into the general focus of organic chemistry yet. The aim of this review is to provide an overview of the developments in the field since 1998.
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Affiliation(s)
- Henning Vogt
- Center for Sustainable and Green Chemistry, Department of Chemistry, Building 201, Technical University of Denmark, DK-2800, Lyngby, Denmark
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3
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Komori H, Inai Y. Electronic CD Study of a Helical Peptide Incorporating Z-Dehydrophenylalanine Residues: Conformation Dependence of the Simulated CD Spectra. J Phys Chem A 2006; 110:9099-107. [PMID: 16854021 DOI: 10.1021/jp056501u] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Electronic circular dichroism (CD) spectra as well as transitions from ground to excited states were predicted for a helical nonapeptide based on alternative sequence--[Z-alpha,beta-dehydrophenylalanine (Delta(Z)Phe)-X]--through semiempirical molecular orbital computation combined with time-dependent (TD) method. The simulation was performed for its various conformers that differ in helix type, helix sense, and Delta(Z)Phe side-chain orientation. These conformational variations have been shown to depend largely on its CD spectra. Comparison between simulated and observed CD profiles reveals that peptide 1 in solution favors a right-handed 3(10)-helix that adopts phenyl (Delta(Z)Phe) planes basically in a vertical orientation with respect to the helix axis. These predictions were essentially supported from CD simulation of a shorter helical analogue at ab inito or density functional TD levels. The theoretical CD-conformation relationship should provide us useful guideline for determination of helix sense in the dehydropeptide, and for estimation of its conformations statistically averaged in solution.
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Affiliation(s)
- Hisatoshi Komori
- Department of Environmental Technology and Urban Planning, Shikumi College, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
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Inai Y, Oshikawa T, Yamashita M, Tagawa K, Hirabayashi T. Crystal structure of achiral nonapeptide Boc-(Aib-?zPhe)4-Aib-OMe at atomic resolution: Evidence for a 310-helix. Biopolymers 2003; 70:310-22. [PMID: 14579304 DOI: 10.1002/bip.10390] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
An x-ray crystallographic analysis was carried out for Boc-(Aib-DeltaZPhe)4-Aib-OMe (1: Boc = t-butoxycarbonyl; Aib = alpha-aminoisobutyric acid; DeltaZPhe = Z-alpha,beta-didehydrophenylalanine) to provide the precise conformational parameters of the octapeptide segment -(Aib-DeltaZPhe)4-. Peptide 1 adopted a typical 3(10)-helical conformation characterized by <phi> = +/-55.8 degrees (50 degrees -65 degrees), <psi> = +/-26.7 degrees (15 degrees -45 degrees), and <omega> = +/-179.5 degrees (168 degrees -188 degrees) for the average values of the -(Aib-DeltaZPhe)4- segment (the range of the eight values). The 3(10)-helix contains 3.1 residues per turn, being close to the "perfect 3(10)-helix" characterized by 3.0 residues per turn. NMR and Fourier transform infrared (FTIR) spectroscopy revealed that the 3(10)-helical conformation at the atomic resolution is essentially maintained in solution. Energy minimization of peptide 1 by semiempirical molecular orbital calculation converged to a 3(10)-helical conformation similar to the x-ray crystallographic 3(10)-helix. The preference for a 3(10)-helix in the -(Aib-DeltaZPhe)4- segment is ascribed to strong inducers of the 3(10)-helix inherent in Aib and DeltaZPhe residues-in particular, the Aib residues tend to stabilize a 3(10)-helix more effectively. Therefore, the -(Aib-DeltaZPhe)4- segment is useful to rationally design an optically inactive 3(10)-helical backbone, which will be of great importance to provide novel insights into noncovalent and covalent chiral interactions of a helical peptide with a chiral molecule.
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Affiliation(s)
- Yoshihito Inai
- Department of Environmental Technology and Urban Planning, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan.
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Ellis TK, Martin CH, Ueki H, Soloshonok VA. Efficient, practical synthesis of symmetrically α,α-disubstituted α-amino acids. Tetrahedron Lett 2003. [DOI: 10.1016/s0040-4039(02)02719-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Tiberghien F, Kurome T, Takesako K, Didier A, Wenandy T, Loor F. Aureobasidins: structure-activity relationships for the inhibition of the human MDR1 P-glycoprotein ABC-transporter. J Med Chem 2000; 43:2547-56. [PMID: 10891114 DOI: 10.1021/jm990955w] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyclic depsipeptide cyclo-[D-Hmp(1)-L-MeVal(2)-L-Phe(3)-L-MePhe(4)-L-Pro(5)-L-aIle+ ++(6)-L-MeVal(7)-L-Leu(8)-L-betaHOMeVal(9)], the antifungal antibiotic aureobasidin A (AbA), was reported to interfere with ATP-binding cassette (ABC) transporters in yeast and mammalian cells, particularly the MDR1 P-glycoprotein (Pgp), a transmembrane phospholipid flippase or "hydrophobic vacuum cleaner" that mediates multidrug resistance (MDR) of cancer cells. In a standardized assay that measures Pgp function by the Pgp-mediated efflux of the calcein-AM Pgp substrate and uses human lymphoblastoid MDR-CEM (VBL(100)) cells as highly resistant Pgp-expressing cells and the cyclic undecapeptide cyclosporin A (CsA) as a reference MDR-reversing agent (IC(50) of 3.4 microM), AbA was found to be a more active Pgp inhibitor (IC(50) of 2.3 microM). Out of seven natural analogues and 18 chemical derivatives of AbA, several were shown to display even more potent Pgp-inhibitory activity. The Pgp-inhibitory activity was increased about 2-fold by some minor modifications such as those found in the naturally occurring aureobasidins AbB ([D-Hiv(1)]-AbA), AbC ([Val(6)]-AbA), and AbD [gammaHOMeVal(9)]-AbA). The replacement of the [Phe(3)-MePhe(4)-Pro(5)] tripeptide by an 8-aminocaprylic acid or the N(7)()-desmethylation of MeVal(7) led to only a 3.3-fold decreased capacity to inhibit Pgp function, suggesting that the Pgp inhibitory potential of aureobasidins, though favored by the establishment of an antiparallel beta-sheet between the [D-Hmp(1)-L-MeVal(2)-L-Phe(3)] and [L-aIle(6)-L-MeVal(7)-L-Leu(8)-] tripeptides, does not critically depend on the occurrence of the [L-Phe(3)-L-MePhe(4)-L-Pro(5)-L-aIle(6)] type II' beta-turn secondary structure. In contrast, the most potent Pgp inhibitors were found among AbA analogues with [betaHO-MeVal(9)] residue alterations, with some data suggesting a negative impact of the [L-Leu(8)-L-betaHOMeVal(9)-D-Hmp(1)] gamma-turn secondary structure on Pgp inhibitory potential. The [2,3-dehydro-MeVal(9)]-AbA was the most potent Pgp inhibitory aureobasidin, being 13-fold more potent than AbA and 19-fold more potent (on a molar basis) than CsA. Finally, there was no correlation between the SAR for the human MDR1 Pgp inhibition and the SAR for Saccharomyces cerevisiae antifungal activity, which is mediated by an inositol phosphoceramide synthase activity.
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Affiliation(s)
- F Tiberghien
- Laboratory of Immunology, Strasbourg 1 University, Illkirch, France
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Slon-Usakiewicz JJ, Sivaraman J, Li Y, Cygler M, Konishi Y. Design of P1‘ and P3‘ Residues of Trivalent Thrombin Inhibitors and Their Crystal Structures. Biochemistry 2000. [DOI: 10.1021/bi992419b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jacek J. Slon-Usakiewicz
- Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, Montreal, Quebec H4P 2R2, Canada
| | - J. Sivaraman
- Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, Montreal, Quebec H4P 2R2, Canada
| | - Yunge Li
- Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, Montreal, Quebec H4P 2R2, Canada
| | - Miroslaw Cygler
- Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, Montreal, Quebec H4P 2R2, Canada
| | - Yasuo Konishi
- Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount Avenue, Montreal, Quebec H4P 2R2, Canada
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Anders R, Wenschuh H, Soskic V, Fischer-Frühholz S, Ohlenschläger O, Dornberger K, Brown LR. A solution NMR study of the selectively 13C, 15N-labeled peptaibol chrysospermin C in methanol. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 1998; 52:34-44. [PMID: 9716249 DOI: 10.1111/j.1399-3011.1998.tb00650.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The conformation of the 19-residue peptaibol chrysospermin C in methanol has been investigated by NMR spectroscopy using selective 15N and 13C labeling of the alpha-aminoisobutyric acid (Aib) residues. Complete 1H and 13C sequential assignments, including stereospecific assignments for the heavily overlapped resonances from the two Cbeta methyl groups of the eight Aib residues, are reported for a peptaibol for the first time. An Aib residue followed by a Pro is an exception to previous suggestions regarding stereospecific assignment of the two Cbeta methyl groups of Aib residues. Local nuclear Overhauser effects and 3J(HNC') and 3J(HNCbeta) scalar couplings indicate that the phi angles of the Aib residues are restricted sterically to local conformations consistent with right-handed helices. Despite these constraints on the eight Aib residues, the NMR data for chrysospermin C in methanol are generally most consistent with an ensemble of transient conformations, including backbone conformations inconsistent with helical structures. Initial NMR measurements for chrysospermin C bound to micelles suggest structural and dynamic differences relative to alamethicin bound to micelles which may be related to differences in gating voltages for formation of ion channels.
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Affiliation(s)
- R Anders
- Institut für Molekulare Biotechnologie, e. V., Jena, Germany
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Balakrishnan R, Parthasarathy R, Ramasubbu N. Crystal structure of a dipeptide Boc-Aib-Phe-OMe. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 1997; 49:371-4. [PMID: 9211217 DOI: 10.1111/j.1399-3011.1997.tb00888.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In order to understand the effect of the restrictions posed by the Aib residue on peptide conformation we studied the crystal structure of a dipeptide tBoc-Aib-Phe-OMe. Crystals of this compound are triclinic, space group P1 with a = 9.600(1) A, b = 10.262(1) A, c = 10.799(1) A, alpha = 98.43 degrees (1), beta = 99.18 degrees (1), gamma = 98.87 degrees (1), V = 1021.69(18) A3 and Z = 2. The structure was solved by direct methods and refined to an R-factor of 4.98%. The backbone conformational angles for the Aib residue in molecule A are in the left-handed helical region, while in molecule B they are in the right-handed helical region. The Phe residue in molecule A is in the right-handed helical conformation, while in molecule B it is in the beta-region. The peptide units are trans and show significant deviation from planarity [(omega 1 = 166.67(5) degrees and omega 2 = -177.9(5)].
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Affiliation(s)
- R Balakrishnan
- Biophysics Department, Roswell Park Cancer Institute, Buffalo, New York, USA
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