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Jwad R, Weissberger D, Hunter L. Strategies for Fine-Tuning the Conformations of Cyclic Peptides. Chem Rev 2020; 120:9743-9789. [PMID: 32786420 DOI: 10.1021/acs.chemrev.0c00013] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cyclic peptides are promising scaffolds for drug development, attributable in part to their increased conformational order compared to linear peptides. However, when optimizing the target-binding or pharmacokinetic properties of cyclic peptides, it is frequently necessary to "fine-tune" their conformations, e.g., by imposing greater rigidity, by subtly altering certain side chain vectors, or by adjusting the global shape of the macrocycle. This review systematically examines the various types of structural modifications that can be made to cyclic peptides in order to achieve such conformational control.
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Affiliation(s)
- Rasha Jwad
- Department of Chemistry, College of Science, Al-Nahrain University, Baghdad, Iraq
| | - Daniel Weissberger
- School of Chemistry, University of New South Wales (UNSW) Sydney, New South Wales 2052, Australia
| | - Luke Hunter
- School of Chemistry, University of New South Wales (UNSW) Sydney, New South Wales 2052, Australia
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Babii O, Afonin S, Ishchenko AY, Schober T, Negelia AO, Tolstanova GM, Garmanchuk LV, Ostapchenko LI, Komarov IV, Ulrich AS. Structure–Activity Relationships of Photoswitchable Diarylethene-Based β-Hairpin Peptides as Membranolytic Antimicrobial and Anticancer Agents. J Med Chem 2018; 61:10793-10813. [DOI: 10.1021/acs.jmedchem.8b01428] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Oleg Babii
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), POB 3640, 76021 Karlsruhe, Germany
| | - Sergii Afonin
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), POB 3640, 76021 Karlsruhe, Germany
| | - Aleksandr Yu. Ishchenko
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Vul. Volodymyrska 60, 01601 Kyiv, Ukraine
- Enamine Ltd., Vul. Chervonotkatska 78, 02066 Kyiv, Ukraine
| | - Tim Schober
- Institute of Organic Chemistry (IOC), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
| | - Anatoliy O. Negelia
- Institute of Biology and Medicine, Taras Shevchenko National University of Kyiv, Prosp. Hlushkova 2, 03022 Kyiv, Ukraine
| | - Ganna M. Tolstanova
- Institute of Biology and Medicine, Taras Shevchenko National University of Kyiv, Prosp. Hlushkova 2, 03022 Kyiv, Ukraine
| | - Liudmyla V. Garmanchuk
- Institute of Biology and Medicine, Taras Shevchenko National University of Kyiv, Prosp. Hlushkova 2, 03022 Kyiv, Ukraine
| | - Liudmyla I. Ostapchenko
- Institute of Biology and Medicine, Taras Shevchenko National University of Kyiv, Prosp. Hlushkova 2, 03022 Kyiv, Ukraine
| | - Igor V. Komarov
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Vul. Volodymyrska 60, 01601 Kyiv, Ukraine
- Enamine Ltd., Vul. Chervonotkatska 78, 02066 Kyiv, Ukraine
- Lumobiotics GmbH, Auerstraße 2, 76227 Karlsruhe, Germany
| | - Anne S. Ulrich
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), POB 3640, 76021 Karlsruhe, Germany
- Institute of Organic Chemistry (IOC), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
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Knijnenburg AD, Spalburg E, de Neeling AJ, Mars-Groenendijk RH, Noort D, Grotenbreg GM, van der Marel GA, Overkleeft HS, Overhand M. Ring-Extended Gramicidin S Analogs Containingcis δ-Sugar Amino Acid Turn Mimetics with Varying Ring Size. Helv Chim Acta 2012. [DOI: 10.1002/hlca.201200497] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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van der Knaap M, Otero JM, Llamas-Saiz A, van Raaij MJ, Lageveen LI, Busscher HJ, Grotenbreg GM, van der Marel GA, Overkleeft HS, Overhand M. Design, synthesis and structural analysis of mixed α/β-peptides that adopt stable cyclic hairpin-like conformations. Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.01.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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5
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Larregola M, Lequin O, Karoyan P, Guianvarc'h D, Lavielle S. β-Amino acids containing peptides and click-cyclized peptide as β-turn mimics: a comparative study with ‘conventional’ lactam- and disulfide-bridged hexapeptides. J Pept Sci 2011; 17:632-43. [DOI: 10.1002/psc.1382] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 04/15/2011] [Accepted: 04/19/2011] [Indexed: 11/11/2022]
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6
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Kapoerchan VV, Knijnenburg AD, Niamat M, Spalburg E, de Neeling AJ, Nibbering PH, Mars-Groenendijk RH, Noort D, Otero JM, Llamas-Saiz AL, van Raaij MJ, van der Marel GA, Overkleeft HS, Overhand M. An Adamantyl Amino Acid Containing Gramicidin S Analogue with Broad Spectrum Antibacterial Activity and Reduced Hemolytic Activity. Chemistry 2010; 16:12174-81. [DOI: 10.1002/chem.201001686] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Reinscheid UM, Zlatopolskiy BD, Griesinger C, Zeeck A, de Meijere A. The Structure of Hormaomycin and One of Its All-Peptide Aza-Analogues in Solution: Syntheses and Biological Activities of New Hormaomycin Analogues. Chemistry 2005; 11:2929-45. [PMID: 15754385 DOI: 10.1002/chem.200400977] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Four new aza-analogues of hormaomycin 1, a secondary metabolite with interesting biological activities produced by Streptomyces griseoflavus, were synthesized and subjected to preliminary tests of their antibiotic activity to provide new insights into the structure-activity relationship studies of this class of compounds. The solution structures of hormaomycin 1 and its aza-analogue 2 a were determined by NMR spectroscopy. The data exhibited a reasonably rigid conformation for both molecules, stabilized by stacking interactions between the aromatic moieties attached to the ring and the side chain. According to NMR-spectral data the aza-analogue epi-2 a has a rather different conformation and indeed shows no antibacterial activity whatsoever.
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Affiliation(s)
- Uwe M Reinscheid
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
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12
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Iseli M, Wagnière G, Brahms JG, Brahms S. Electronic Properties and Optical Activity of Oligopeptides. III. Some cyclohexapeptides with glycine,L- andD-alanine. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19790620402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Lee DL, Hodges RS. Structure-activity relationships of de novo designed cyclic antimicrobial peptides based on gramicidin S. Biopolymers 2003; 71:28-48. [PMID: 12712499 DOI: 10.1002/bip.10374] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The cyclic beta-sheet structure possessed by the 10-residue antibiotic peptide gramicidin S was taken as the structural framework for the de novo design of biologically active peptides with membrane-active properties. We have shown from previous studies that gramicidin S is a broad-spectrum antibiotic effective against Gram-positive bacteria, Gram-negative bacteria, and fungi, but is toxic to human red blood cells. We tested the effect of ring size on antimicrobial activity and hemolytic activity on peptides varying from 4 to 16 residues. Interestingly, we were able to dissociate hemolytic activity and antimicrobial activity by increasing the ring size of the peptide to 14 residues (peptide GS14). Furthermore, we increased specificity for microbial membranes while decreasing toxicity to red blood cells by substituting enantiomers (D-amino acids for L-amino acids and vice versa) into the GS14 sequence. The enantiomeric substitutions all disrupted beta-sheet structure in benign medium and decreased peptide amphipathicity. The least amphipathic peptide, produced by substituting a D-Lys at position 4 of GS14 (peptide GS14K4), also had the highest therapeutic index, i.e., highest degree of specificity for microbial cells over human cells. Solution structures of GS14 analogs solved by NMR spectroscopy showed that the D-amino acid side chain was located on the nonpolar face of GS14K4. Another analog, a beta-sheet peptide with reduced amphipathicity (peptide GS14 K3L4), also had a lysine (lysine 3) on the nonpolar face as determined by the NMR structure. Both GS14K4 and GS14 K3L4 had reduced amphipathicity relative to GS14 and much higher therapeutic indices. Finally, the alteration of the nonpolar face hydrophobicity of GS14K4 analogs provided a range of activities and specificities, where the peptides with the intermediate hydrophobicities among the series had the highest therapeutic indices. The optimal peptide hydrophobicities varied depending on the microorganism being tested, with higher hydrophobicity requirements against Gram-positive bacteria and yeast compared with Gram-negative microorganisms. The net result of these studies suggests that it is possible to rationally design a cyclic membrane-active antimicrobial peptide with high specificity towards prokaryotic (bacterial and fungal) membranes and minimal toxicity to eukaryotic (e.g., mammalian) membranes.
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Affiliation(s)
- Darin L Lee
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
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Gibbs AC, Bjorndahl TC, Hodges RS, Wishart DS. Probing the structural determinants of type II' beta-turn formation in peptides and proteins. J Am Chem Soc 2002; 124:1203-13. [PMID: 11841288 DOI: 10.1021/ja011005e] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The structural determinants of type II' beta-turns were probed through a comprehensive CD, NMR, and molecular dynamics analysis of 10 specially designed beta-hairpin peptides. The peptide model used in this study is a synthetic, water-soluble, 14-residue cyclic analogue of gramicidin S which contains two well-defined type II' beta-turns connected by a highly stable, amphipathic, antiparallel beta-sheet. A variety of coded and noncoded amino acids were systematically substituted in one of the two type II' turns to analyze the effects of backbone chirality, side-chain steric restriction, and side-chain/side-chain interactions. beta-Sheet content (as measured through a variety of experimental methods), molecular dynamics, and 3D structural analysis of the turn regions were used to assess the effects of each amino acid substitution on type II' beta-turn stabilization. Our results demonstrate that backbone heterochirality, which determines equatorial and axial side-chain orientation at the i+1 and i+2 residues of type II' turns, may account for up to 60% of type II' beta-turn stabilization. Steric restriction through side-chain N-alkylation appears to enhance type II' beta-turn propensity and may account for up to 20% of type II' beta-turn stabilization. Finally, aromatic/proline side-chain interactions appear to account for approximately 10% of type II' beta-turn stabilization. We believe this information could be particularly useful for the prediction of beta-turn propensity, the development of peptide-based drugs, and the de novo design of peptides, proteins, and peptidyl mimetics.
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Affiliation(s)
- Alan C Gibbs
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2N8
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Renner C, Cramer J, Behrendt R, Moroder L. Photomodulation of conformational states. II. Mono- and bicyclic peptides with (4-aminomethyl)phenylazobenzoic acid as backbone constituent. Biopolymers 2000; 54:501-14. [PMID: 10984402 DOI: 10.1002/1097-0282(200012)54:7<501::aid-bip30>3.0.co;2-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
It has been reported that backbone cyclization of octapeptides with the photoresponsive (4-aminomethyl)phenylazobenzoic acid imparts sufficient restraints to induce and stabilize ordered conformations of the peptide backbone in both the cis- and trans-azo-isomers (L. Ulysse, J. Cubillos, and J. Chmielewski, Journal of the American Chemical Society, 1995, Vol. 117, pp. 8466-8467). Correspondingly, the active-site octapeptide fragment H-Ala-Cys-Ala-Thr-Cys-Asp-Gly-Phe-OH [134-141] of thioredoxin reductase, with its high preference for a 3(10)-helix turn conformation centered on the Thr-Cys sequence, was backbone cyclized with this azobenzene moiety in the attempt to design a photoresponsive system where the conformational states of the peptide backbone are dictated by the configuration of the azobenzene and can be further modulated by the disulfide bridge. Nuclear magnetic resonance conformational analysis of the monocyclic compound clearly revealed the presence of two conformational families in both the cis- and trans-azo configuration. Of the higher populated conformational families, the structure of the trans-isomer seems like a pretzel-like folding, while the cis-isomer relaxes into a significantly less defined conformational state that does not exhibit any regular structural elements. Further restrictions imparted by disulfide bridging of the peptide moiety leads to an even better defined conformation for the trans-azo-isomer, whereas the cis-isomer can be described as a frustrated system without pronounced energy minima and thus with little conformational preferences. Our findings would suggest that this photoresponsive peptide template may not be of general usefulness for light-induced conformational transitions between two well-defined conformational states at least under the experimental conditions employed, even in the bicyclic form. However, trans --> cis isomerization of the bicyclic peptide is accompanied by a switch from a well-defined conformation to an ensemble of possible conformations.
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Affiliation(s)
- C Renner
- Max-Planck Institut für Biochemie, 82152 Martinsried, Germany
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Gibbs AC, Kondejewski LH, Gronwald W, Nip AM, Hodges RS, Sykes BD, Wishart DS. Unusual beta-sheet periodicity in small cyclic peptides. NATURE STRUCTURAL BIOLOGY 1998; 5:284-8. [PMID: 9546219 DOI: 10.1038/nsb0498-284] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cyclic peptide homologs of gramicidin S containing 6, 8, 10, 12, 14 and 16 residues were synthesized and characterized using circular dichroism (CD) and 1H NMR spectroscopy. Based on the three-dimensional structures generated from these data we have found strong evidence of a periodic sequence-length dependence on beta-sheet content. In particular, peptides of length 6, 10 and 14 residues exhibit a high beta-sheet content, while peptides of 8, 12 and 16 residues appear to exist as random coils. This unusual beta-sheet periodicity may have important implications in our understanding of beta-sheet formation and in the design of constrained beta-sheet and beta-hairpin mimics.
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Affiliation(s)
- A C Gibbs
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Canada
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Kondejewski LH, Farmer SW, Wishart DS, Kay CM, Hancock RE, Hodges RS. Modulation of structure and antibacterial and hemolytic activity by ring size in cyclic gramicidin S analogs. J Biol Chem 1996; 271:25261-8. [PMID: 8810288 DOI: 10.1074/jbc.271.41.25261] [Citation(s) in RCA: 148] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We have evaluated the effect of ring size of gramicidin S analogs on secondary structure, lipid binding, lipid disruption, antibacterial and hemolytic activity. Cyclic analogs with ring sizes ranging from 4 to 14 residues were designed to maintain the amphipathic character as found in gramicidin S and synthesized by solid phase peptide synthesis. The secondary structure of these peptides showed a definite periodicity in beta-sheet content, with rings containing 6, 10, and 14 residues exhibiting beta-sheet structure, and rings containing 8 or 12 residues being largely disordered. Peptides containing 4 or 6 residues did not bind lipopolysaccharide, whereas longer peptides showed a trend of increasing binding affinity for lipopolysaccharide with increasing length. Destabilization of Escherichia coli outer membranes was only observed in peptides containing 10 or more residues. Peptides containing fewer than 10 residues were completely inactive and exhibited no hemolytic activity. The 10-residue peptide showed an activity profile similar to that of gramicidin S itself, with activity against Gram-positive and Gram-negative microorganisms as well as yeast, but also showed high hemolytic activity. Differential activities were obtained by increasing the size of the ring to either 12 or 14 residues. The 14-residue peptide showed no antibiotic activity but exhibited increased hemolytic activity. The 12-residue peptide lost activity against Gram-positive bacteria, retained activity against Gram-negative microorganisms and yeast, but displayed decreased hemolytic activity. Biological activities in the 12-residue peptide were optimized by a series of substitutions in residues comprising both hydrophobic and basic sites resulting in a peptide that exhibited activities comparable with gramicidin S against Gram-negative microorganisms and yeast but with substantially lower hemolytic activity. Compared with gramicidin S, the best analog showed a 10-fold improvement in antibiotic specificity for Gram-negative microorganisms and a 7-fold improvement in specificity for yeast over human erythrocytes as determined by a therapeutic index. These results indicate that it is possible to modulate structure and activities of cyclic gramicidin S analogs by varying ring sizes and further show the potential for developing clinically useful antibiotics based on gramicidin S.
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Affiliation(s)
- L H Kondejewski
- Department of Biochemistry and the Protein Engineering Network of Centres of Excellence, University of Alberta, Edmonton, Alberta, T6G 2S2
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Ma S, Richardson JF, Spatola AF. Crystal structures of two cyclic pseudopentapeptides containing psi[CH2S] and psi[CH2SO] backbone surrogates. Biopolymers 1993; 33:1101-10. [PMID: 8343587 DOI: 10.1002/bip.360330712] [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: 01/30/2023]
Abstract
The solid state conformations of cyclo [Gly-Pro psi[CH2S] Gly-D-Phe-Pro] and cyclo [Gly-Pro psi[CH2-(S)-SO]Gly-D-Phe-Pro] have been characterized by X-ray diffraction analysis. Crystals of the sulfide trihydrate are orthorhombic, P2(1)2(1)2(1), with a = 10.156(3) A, b = 11.704(3) A, c = 21.913(4) A, and Z = 4. Crystals of the sulfoxide are monoclinic, P2(1) with a = 10.662(1) A, b = 8.552(3) A, c = 12.947(2) A, beta = 94.28(2), and Z = 2. Unlike their all-amide parent, which adopts an all-trans backbone conformation and a type II beta-turn encompassing Gly-Pro-Gly-D-Phe, both of these peptides contain a cis Gly1-Pro2 bond and form a novel turn structure, i.e., a type II' beta-turn consisting of Gly-D-Phe-Pro-Gly. The turn structure in each of these peptides is stabilized by an intramolecular H bond between the carbonyl oxygen of Gly1 and the amide proton of D-Phe4. In the cyclic sulfoxide, the sulfinyl group is not involved in H bonding despite its strong potential as a hydrogen-bond acceptor. The crystal structure made it possible to establish the absolute configuration of the sulfinyl group in this peptide. The two crystal structures also helped identify a type II' beta-turn in the DMSO-d6 solution conformers of these peptides.
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Affiliation(s)
- S Ma
- Department of Chemistry, University of Louisville, Kentucky 40292
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Witiak DT, Wei Y. Dioxopiperazines: chemistry and biology. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 1990; 35:249-363. [PMID: 2290982 DOI: 10.1007/978-3-0348-7133-4_7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- D T Witiak
- Division of Medicinal Chemistry, College of Pharmacy, Ohio State University, Columbus 43210
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Kunz H, Lerchen HG. Synthese des all-L-konfigurierten Cyclohexadepsipeptidscyclo-[L-Val-L-Lac]3 nach der Peoc/Säurechlorid-Methode. Angew Chem Int Ed Engl 1984. [DOI: 10.1002/ange.19840961018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Kessler H, Schuck R, Siegmeier R, Bats JW, Fuess H, Förster H. Peptidkonformationen, 22. Die Konformation voncyclo-[Pro2-(NB)Gly] im Kristall und in Lösung durch Röntgenstrukturanalyse und ein- und zweidimensionale NMR-Spektroskopie. ACTA ACUST UNITED AC 1983. [DOI: 10.1002/jlac.198319830208] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Sakurai A, Okumura Y. Synthesis of Viscumamide and Its Analogs. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1979. [DOI: 10.1246/bcsj.52.540] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Walter J, Wright J. 13C-15N spin-spin coupling constants of amides: H-bonding effects in a cyclohexapeptide. Tetrahedron Lett 1979. [DOI: 10.1016/s0040-4039(01)86462-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Sugihara T, Imanishi T, Higashimura T. Studies on cyclic peptides. IV. Conformation of cyclo(Sar-Sar-Gly)2, cyclo(Sar)6, and cyclo(Sar-Gly-Gly)2 and their conformational change induced by alkali thiocyanates. Biopolymers 1976; 15:1529-42. [PMID: 963248 DOI: 10.1002/bip.1976.360150808] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Urry DW, Onishi T. Studies on the conformations and interactions of elastin. Proton magnetic resonance of the repeating tetramer. Biopolymers 1974; 13:1223-42. [PMID: 4854480 DOI: 10.1002/bip.1974.360130614] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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26
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Grathwohl C, Schwyzer R, Tun-kyi A, Wüthrich K. Carbon-13 NMR spectra of cyclo-glycyl-L-prolyl-glycyl-glycyl-L-prolyl-glycyl: assignment of the carbonyl resonances. FEBS Lett 1973; 29:271-274. [PMID: 11946930 DOI: 10.1016/0014-5793(73)80036-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- C Grathwohl
- Institut für Molekularbiologie und Biophysik, Eidgenössische Technische Hochschule, 8049, Zürich, Switzerland
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Schwyzer R, Grathwohl C, Meraldi JP, Tun-Kyi A, Vogel R, Wüthrich K. 254. The solution conformation of cyclo-glycyl-L-prolyl-glycyl-glycyl-L-prolyl-glycyl. Communication 22 (preliminary) on homodetic cyclic polypeptides. Helv Chim Acta 1972; 55:2545-9. [PMID: 4637276 DOI: 10.1002/hlca.19720550731] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Meraldi JP, Schwyzer R, Tun-Kyi A, Wüthrich K. Conformational studies of cyclic pentapeptides by proton magnetic resonance spectroscopy. Helv Chim Acta 1972; 55:1962-73. [PMID: 5077584 DOI: 10.1002/hlca.19720550614] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Cary LW, Takita T, Ohnishi M. A study of the secondary structure of ilamycin B(1) by 300 MHz proton magnetic resonance. FEBS Lett 1971; 17:145-148. [PMID: 11946017 DOI: 10.1016/0014-5793(71)80584-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Lewis W. Cary
- NMR Laboratories, Varian Associates, 94303, Palo Alto, Calif., USA
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A study of the conformational states of cyclopeptide systems IV. NMR spectra of cyclohexapeptides constructed of alanine and glycine residues: Chemical shifts and intramolecular hydrogen bonds. Chem Nat Compd 1971. [DOI: 10.1007/bf00569005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Taylor A. The occurrence, chemistry, and toxicology of the microbial peptide-lactones. ADVANCES IN APPLIED MICROBIOLOGY 1970; 12:189-276. [PMID: 4920196 DOI: 10.1016/s0065-2164(08)70586-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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