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Zotti MD, Formaggio F, Crisma M, Peggion C, Moretto A, Toniolo C. Handedness preference and switching of peptide helices. Part I: Helices based on protein amino acids. J Pept Sci 2014; 20:307-22. [DOI: 10.1002/psc.2638] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 12/20/2022]
Affiliation(s)
- Marta De Zotti
- Department of Chemistry; University of Padua; Padua Italy
| | | | | | | | | | - Claudio Toniolo
- Department of Chemistry; University of Padua; Padua Italy
- ICB, Padua Unit; CNR; Italy
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2
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Casanovas J, Revilla-López G, Crisma M, Toniolo C, Alemán C. Factors Governing the Conformational Tendencies of Cα-Ethylated α-Amino Acids: Chirality and Side-Chain Size Effects. J Phys Chem B 2012; 116:13297-307. [DOI: 10.1021/jp3045115] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jordi Casanovas
- Departament
de Química, Escola Politècnica Superior, Universitat de Lleida, 25001 Lleida, Spain
| | - Guillermo Revilla-López
- Departament d’Enginyeria Química,
E. T. S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, 08028
Barcelona, Spain
| | - Marco Crisma
- ICB, Padova
Unit, CNR, Department of Chemistry, University of Padova, 35131 Padova, Italy
| | - Claudio Toniolo
- ICB, Padova
Unit, CNR, Department of Chemistry, University of Padova, 35131 Padova, Italy
| | - Carlos Alemán
- Departament d’Enginyeria Química,
E. T. S. d’Enginyeria Industrial de Barcelona, Universitat Politècnica de Catalunya, 08028
Barcelona, Spain
- Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, 08028 Barcelona, Spain
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3
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Laufer B, Chatterjee J, Frank AO, Kessler H. Can N-methylated amino acids serve as substitutes for prolines in conformational design of cyclic pentapeptides? J Pept Sci 2009; 15:141-6. [PMID: 18985637 DOI: 10.1002/psc.1076] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The incorporation of proline into cyclic peptides seems to be the most promising way to induce beta-turn structures. Recently, however, it was shown that N-methylated amino acids might be even better suited than proline for introducing turn structures. Another property of proline, the ability to effect cis-peptide bonds, has also been reported for N-methylated amino acids. These findings raise the question if it might be possible to replace a proline by an N-methylated amino acid without altering the desired conformational features. The most important benefit of replacing proline by an N-methylated residue is that one recovers the side-chain functionalities, which could be used for enhancing binding selectivity, or to tune a cyclic peptide concerning its pharmacological properties.Here, we compare cyclic peptides containing one or two prolines or N-methylated alanines and a combination of both with respect to preferred conformations and cis-peptide bonds. In addition, the positions have been investigated where an N-alkylated amino acid has to be incorporated to mimic structural aspects usually introduced by proline residues.
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Affiliation(s)
- Burkhardt Laufer
- Center for Integrated Protein Science at the Department Chemie, Technische Universität München, Lichtenbergstrasse 4, Garching, D-85747 Germany
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CARBONE F, LEACH S. Studies of repeating synthetic peptides designed to adopt a cross-β conformation. ACTA ACUST UNITED AC 2009. [DOI: 10.1111/j.1399-3011.1985.tb03200.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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5
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Moretto A, Formaggio F, Kaptein B, Broxterman QB, Wu L, Keiderling TA, Toniolo C. First homo-peptides undergoing a reversible 310-helix/α-helix transition: Critical main-chain length. Biopolymers 2008; 90:567-74. [DOI: 10.1002/bip.21016] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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6
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Andreetto E, Peggion C, Crisma M, Toniolo C. Handedness control of peptide helices by amino acid side-chain chirality: Ile/aIle peptides. Biopolymers 2006; 84:490-501. [PMID: 16680718 DOI: 10.1002/bip.20534] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A set of four hexapeptide sequences, each characterized by four strongly helicogenic Aib residues and all combinations of two isomeric Ile/aIle residues at positions 2 and 5, was synthesized by solution methods and fully characterized. A detailed solution (by FT-IR absorption, NMR, and CD techniques) and solid/crystalline state (by X-ray diffraction) conformational investigation allowed us to validate our assumption that all four peptides are folded in well-developed 3(10)-helical structures. However, the most relevant conformational conclusion extracted from the present 3D-analysis is that the handedness of the 3(10)-helical structures formed does not seem to be sensitive to the configurational change at the beta-carbon atom of the constituent Ile versus the diastereomeric aIle residues (in other words, the dominant control on this important structural parameter appears to be exerted by the chirality of the amino acid alpha-carbon atom). These results complement published findings on the diverging relative stabilities of the intermolecularly H-bonded beta-sheet structures generated by Ile versus aIle homo-oligopeptides.
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Affiliation(s)
- Erika Andreetto
- Institute of Biomolecular Chemistry, CNR, Department of Chemistry, University of Padua, 35131 Padua, Italy
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7
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Shinchuk LM, Sharma D, Blondelle SE, Reixach N, Inouye H, Kirschner DA. Poly-(L-alanine) expansions form core β-sheets that nucleate amyloid assembly. Proteins 2005; 61:579-89. [PMID: 16114037 DOI: 10.1002/prot.20536] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Expansion to a total of 11-17 sequential alanine residues from the normal number of 10 in the polyadenine-binding protein nuclear-1 (PABPN1) results in formation of intranuclear, fibrillar inclusions in skeletal muscle and hypothalamic neurons in adult-onset, dominantly inherited oculopharyngeal muscular dystrophy (OPMD). To understand the role that homopolymeric length may play in the protein misfolding that leads to the inclusions, we analyzed the self-assembly of synthetic poly-(L-alanine) peptides having 3-20 residues. We found that the conformational transition and structure of polyalanine (polyAla) assemblies in solution are not only length-dependent but also are determined by concentration, temperature, and incubation time. No beta-sheet complex was detected for those peptides characterized by n < 8, where n is number of alanine residues. A second group of peptides with 7 < n < 15 showed varying levels of complex formation, while for those peptides having n > 15, the interconversion process from the monomeric to the beta-sheet complex was complete under any of the tested experimental conditions. Unlike the typical tinctorial properties of amyloid fibrils, polyalanine fibrils did not show fluorescence with thioflavin T or apple-green birefringence with Congo red; however, like amyloid, X-ray diffraction showed that the peptide chains in these fibrils were oriented normal to the fibril axis (i.e., in the cross-beta arrangement). Neighboring beta-sheets are quarter-staggered in the hydrogen-bonding direction such that the alanine side-chains were closely packed in the intersheet space. Strong van der Waals contacts between side-chains in this arrangement likely account for the high stability of the macromolecular fibrillar complex in solution over a wide range of temperature (5-85 degrees C), and pH (2-10.5), and its resistance to denaturant (< 8 M urea) and to proteases (protease K, trypsin). We postulate that a similar stabilization of an expanded polyalanine stretch could form a core beta-sheet structure that mediates the intermolecular association of mutant proteins into fibrillar inclusions in human pathologies.
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Affiliation(s)
- Leonid M Shinchuk
- Department of Biology, Boston College, Chestnut Hill, Massachusetts 02467-3811, USA
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Abstract
Circular dichroism spectra of proteins are sensitive to protein secondary structure. The CD spectra of alpha-rich proteins are similar to those of model alpha-helices, but beta-rich proteins exhibit CD spectra that are reminiscent of CD spectra of either model beta-sheets or unordered polypeptides. The existence of these two types of CD spectra for beta-rich proteins form the basis for their classification as betaI- and betaII-proteins. Although the conformation of beta-sheets is largely responsible for the CD spectra of betaI-proteins, the source of betaII-protein CD, which resembles that of unordered polypeptides, is not completely understood. The CD spectra of unordered polypeptides are similar to that of the poly(Pro)II helix, and the poly(Pro)II-type (P2) structure forms a significant fraction of the unordered conformation in globular proteins. We have compared the beta-sheet and P2 structure contents in beta-rich proteins to understand the origin of betaII-protein CD. We find that betaII-proteins have a ratio of P2 to beta-sheet content greater than 0.4, whereas for betaI-proteins this ratio is less than 0.4. The beta-sheet content in betaI-proteins is generally higher than that in betaII-proteins. The origin of two classes of CD spectra for beta-rich proteins appears to lie in their relative beta-sheet and P2 structure contents.
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Affiliation(s)
- Narasimha Sreerama
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins 80523, USA
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Sharma D, Sharma S, Pasha S, Brahmachari SK. Peptide models for inherited neurodegenerative disorders: conformation and aggregation properties of long polyglutamine peptides with and without interruptions. FEBS Lett 1999; 456:181-5. [PMID: 10452554 DOI: 10.1016/s0014-5793(99)00933-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Several neurodegenerative diseases are caused by expansion of polyglutamine repeats in the affected proteins. In spino-cerebellar ataxia type 1 (SCA1), histidine interruptions have been reported to mitigate the pathological effects of long glutamine stretches. To understand this phenomenon, we investigated the conformational preferences of peptides containing both the uninterrupted polyglutamine stretches and those with histidine interruption(s) as seen in SCA1 normals. Our study suggests that substitution of histidines by glutamines induces a conformational change which results in decreased solubility and increased aggregation. Our findings also suggest that all the polyglutamine peptides with and without interruption(s) adopt a beta-structure and not random coil.
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Affiliation(s)
- D Sharma
- Functional Genomics Unit, Centre for Biochemical Technology, Delhi, India
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Polese A, Mondini S, Bianco A, Toniolo C, Scorrano G, Guldi DM, Maggini M. Solvent-Dependent Intramolecular Electron Transfer in a Peptide-Linked [Ru(bpy)3]2+−C60 Dyad. J Am Chem Soc 1999. [DOI: 10.1021/ja983421d] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alessandra Polese
- Contribution from the Centro Meccanismi Reazioni Organiche and Centro Studio Biopolimeri del CNR, Dipartimento di Chimica Organica, Università di Padova, Via Marzolo 1, 35131 Padova, Italy, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46656
| | - Simonetta Mondini
- Contribution from the Centro Meccanismi Reazioni Organiche and Centro Studio Biopolimeri del CNR, Dipartimento di Chimica Organica, Università di Padova, Via Marzolo 1, 35131 Padova, Italy, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46656
| | - Alberto Bianco
- Contribution from the Centro Meccanismi Reazioni Organiche and Centro Studio Biopolimeri del CNR, Dipartimento di Chimica Organica, Università di Padova, Via Marzolo 1, 35131 Padova, Italy, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46656
| | - Claudio Toniolo
- Contribution from the Centro Meccanismi Reazioni Organiche and Centro Studio Biopolimeri del CNR, Dipartimento di Chimica Organica, Università di Padova, Via Marzolo 1, 35131 Padova, Italy, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46656
| | - Gianfranco Scorrano
- Contribution from the Centro Meccanismi Reazioni Organiche and Centro Studio Biopolimeri del CNR, Dipartimento di Chimica Organica, Università di Padova, Via Marzolo 1, 35131 Padova, Italy, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46656
| | - Dirk M. Guldi
- Contribution from the Centro Meccanismi Reazioni Organiche and Centro Studio Biopolimeri del CNR, Dipartimento di Chimica Organica, Università di Padova, Via Marzolo 1, 35131 Padova, Italy, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46656
| | - Michele Maggini
- Contribution from the Centro Meccanismi Reazioni Organiche and Centro Studio Biopolimeri del CNR, Dipartimento di Chimica Organica, Università di Padova, Via Marzolo 1, 35131 Padova, Italy, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46656
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11
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Bode KA, Applequist J. Improved Theoretical π−π* Absorption and Circular Dichroic Spectra of Helical Polypeptides Using New Polarizabilities of Atoms and NC‘O Chromophores. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp962120s] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kimberly A. Bode
- Department of Biochemistry and Biophysics, Iowa State University, Ames, Iowa 50011
| | - Jon Applequist
- Department of Biochemistry and Biophysics, Iowa State University, Ames, Iowa 50011
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13
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Perczel A, Park K, Fasman GD. Deconvolution of the circular dichroism spectra of proteins: the circular dichroism spectra of the antiparallel beta-sheet in proteins. Proteins 1992; 13:57-69. [PMID: 1594578 DOI: 10.1002/prot.340130106] [Citation(s) in RCA: 93] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A recently developed algorithm, called Convex Constraint Analysis (CCA), was successfully applied to determine the circular dichroism (CD) spectra of the pure beta-pleated sheet in globular proteins. On the basis of X-ray diffraction determined secondary structures, the original data set used (Perczel, A., Hollosi, M., Tusnady, G. Fasman, G.D. Convex constraint analysis: A natural deconvolution of circular dichroism curves of proteins, Prot. Eng., 4:669-679, 1991), was improved by the addition of proteins with high beta-pleated sheet content. The analysis yielded CD curves of the pure components of the main secondary structural elements (alpha-helix, antiparallel beta-pleated sheet, beta-turns, and unordered conformation), as well as a curve attributed to the "aromatic contribution" in the wavelength range of 195-240 nm. Upon deconvolution the curves obtained were assigned to various secondary structures. The calculated weights (percentages determining the contributions of each pure component curve in the measured CD spectra of a given protein) were correlated with the X-ray diffraction determined percentages in an assignment procedure and were evaluated. The Pearson product correlation coefficients (R) are significant for all five components. The new pure component curves, which were obtained through deconvolution of the protein CD spectra alone, are promising candidates for determining the percentages of the secondary structural components in globular proteins without the necessity of adopting an X-ray database. The CD spectrum of the CheY protein was interesting because it has the characteristic shape associated with the alpha-helical structure, but upon analysis yielded a considerable amount of beta-sheet in agreement with the X-ray structure.
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Affiliation(s)
- A Perczel
- Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02254-9110
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Manning MC, Illangasekare M, Woody RW. Circular dichroism studies of distorted alpha-helices, twisted beta-sheets, and beta turns. Biophys Chem 1988; 31:77-86. [PMID: 3233294 DOI: 10.1016/0301-4622(88)80011-5] [Citation(s) in RCA: 232] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Theoretical models for calculating the circular dichroism (CD) of biopolymers have been constructed which allow the evaluation of the effects of geometric distortions within regular secondary structures. Outward tilting of the carbonyl group within alpha-helical structures yields calculated CD spectra with diminished intensity and a red-shifted maximum near 190 nm. The alpha II-helix provides an extreme example of this type of alpha-helix distortion. It is predicted that a mixture of alpha and alpha II structures in bacteriorhodopsin can account for its anomalous CD spectrum. The minimum length of alpha-helix required to produce an alpha-helix-like CD spectrum is calculated to be two to three turns (seven to eleven residues), while helices greater than 30 residues should provide adequate models of an infinite helix. Twisting of beta-sheets is predicted to lead to an increase in CD intensity and significant shifts in band position. Calculated CD spectra for beta-turn models are accurate for types II and II', but appear to be inadequate for type I turns.
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Affiliation(s)
- M C Manning
- Department of Biochemistry, Colorado State University, Fort Collins 80523
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Joseph M, Nagaraj R. Circular dichroism studies on a synthetic peptide corresponding to the membrane-spanning region of vesicular stomatitis virus G protein and its fatty acyl derivative. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 911:231-7. [PMID: 3026485 DOI: 10.1016/0167-4838(87)90012-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The conformations of synthetic peptides Lys-Phe-Phe-Phe-Ile-Ile-Gly-Leu-Ile-Ile-Gly-Leu-Phe-OCH3 and Lys(epsilon-palmitoyl)-Phe-Phe-Phe-Ile-Ile-Gly-Leu-Ile-Ile-Gly-Leu-Phe-O CH3, which constitute a part of the membrane-spanning region of the vesicular stomatitis virus G protein, have been studied by circular dichroism (CD) spectroscopy. Secondary structural features are observed for both peptides in trifluoroethanol, methanol, aqueous mixtures of trifluoroethanol and methanol and in a micellar environment. In trifluoroethanol, the CD spectra indicate the presence of a helical conformation, whereas in aqueous mixtures of organic solvents, both helical and beta-conformations are observed. While fatty acid acylation does not directly modulate peptide conformation, it promotes self-association of the acylated peptide and association with micelles. In a micellar environment, the acylated peptide adopts an alpha-helical conformation.
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16
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Ribeiro AA, Saltman R, Goodman M. Conformational analyses of polyoxyethylene-bound homo-oligo-L-glutamates in a helix-supporting environment trifluoroethanol. Biopolymers 1985; 24:2469-93. [PMID: 2418893 DOI: 10.1002/bip.360241220] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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17
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Ikeda S, Tomiyama T. Molecular Weight and Conformation of Poly(S-[(3-hydroxypropyl)-carbamoylmethyl]-L-cysteine) in Various Solvents. Polym J 1982. [DOI: 10.1295/polymj.14.33] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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Toniolo C, Bonora G, Salardi S. Study of the relationship between conformation and nature of side chains in linear oligopeptides: homologous series derived from β-branched amino acid residues. Int J Biol Macromol 1981. [DOI: 10.1016/0141-8130(81)90093-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Mayr W, Jung G. Darstellung, Charakterisierung und Konformationsbestimmung eines Undekapeptidhydrazids der N-terminalen Alamethicin-Sequenz. ACTA ACUST UNITED AC 1980. [DOI: 10.1002/jlac.198019801006] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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20
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El Rahman SA, Anzinger H, Mutter M. Relationship between conformation and physicochemical properties of polypeptides. I. Synthesis of homo- and co-oligopeptides by the liquid-phase method. Biopolymers 1980; 19:173-187. [DOI: 10.1002/bip.1980.360190112] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Rueda DR, Spadon P, Bonora GM, Zanotti G. X-ray study on homo-oligopeptides t-BOC-(D-Ala)7-OMe and HCl.H(D-Ala)7-OMe. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1979; 13:374-8. [PMID: 457332 DOI: 10.1111/j.1399-3011.1979.tb01895.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Observations of extended peptide chains, whose direction is perpendicular to the fiber axis (cross-beta-structures) have hitherto been confined to fibrous proteins and to some synthetic polydisperse polypeptides of rather low molecular weight. This structure has now been found in some monodisperse linear homo-oligopeptides with aliphatic hydrocarbon side chains. X-ray diffraction photographs of t-Boc-(D-Ala)7-OMe and HCl.H(D-Ala)7-OMe show characteristic reflections for this form. In addition, the good orientation of suitably prepared specimens has enabled a fairly complete determination of the unit cell of the heptapeptides to be made. t-Boc-(D-Ala)7-OMe and HCl.H(D-Ala)7-OMe molecules are packed in a monoclinic lattice with a = 4.80, b = 34.5, c = 5.82 A, beta = 65.6 degrees and a = 4.80, b = 29.5, c = 5.82 A, beta = 65.6 degrees, respectively. It has not been possible to establish whether the arrangement of the chains within the sheets is parallel or antiparallel.
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22
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Baron MH, De Loze C, Toniolo C, Fasman GD. Infrared and Raman study in the solid state of fully protected, monodispersed homooligopeptides ofL-valine,L-isoleucine, andL-phenylalanine. Biopolymers 1979. [DOI: 10.1002/bip.1979.360180216] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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23
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Widmer U, Lorenzi GP, Pino P. The influence of asymmetric carbon atoms of the side chains on the conformational properties of polypeptides: Comparison of diastereomeric homooligopeptides ofL-isoleucine andD-alloisoleucine. Biopolymers 1979. [DOI: 10.1002/bip.1979.360180202] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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24
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Linear oligopeptides: 53. Conformations of poly(ethylene glycol)-bound alanine and valine homo-l-oligopeptides in alcoholic solution. POLYMER 1978. [DOI: 10.1016/0032-3861(78)90089-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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25
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Naider F, Becker JM, Ribeiro A, Goodman M. The effect of homologos amini acid replacement on the conformation of oligopeptides. III. CD studies on co-oligopeptides of methionine and valine or methionine and glycine in organic solution. Biopolymers 1978. [DOI: 10.1002/bip.1978.360170914] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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26
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Becker JM, Naider F. The effect of homologous amino acid replacement on the conformation of oligopeptides. I. Synthesis of co-oligopeptides containing methionine and valine. Biopolymers 1978. [DOI: 10.1002/bip.1978.360170912] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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27
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Baron MH, De Loze C, Toniolo C, Fasman GD. Structure in solution of protected homo-oligopeptides ofL-valine,L-isoleucine, and L-phenylalanine: An infrared absorption study. Biopolymers 1978. [DOI: 10.1002/bip.1978.360170915] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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28
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Toniolo C, Bonora GM, Palumbo M, Peggion E, Stevens ES. Linear oligopeptides. XLIII. Study of the relationship between conformation and nature of side chain: Homologous series derived from ?-branched amino acid residues. Biopolymers 1978. [DOI: 10.1002/bip.1978.360170708] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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