276
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Toniolo C, Crisma M, Fabiano N, Melchiorri P, Negri L, Krause JA, Eggleston DS. A crystal-state, solution and theoretical study of the preferred conformation of linear C alpha, alpha-diphenylglycine derivatives and dipeptides with potential anticonvulsant activity. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1994; 44:85-95. [PMID: 7960408 DOI: 10.1111/j.1399-3011.1994.tb00408.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Several linear molecules containing the C alpha, alpha-diphenylglycine residue were prepared as potential anticonvulsants. The conformational preferences of the C alpha, alpha-diphenylglycine residue were assessed in these synthetic derivatives and dipeptides by X-ray diffraction, FTIR absorption and 1H NMR techniques, and by conformational energy computations. Five (out of six) derivatives adopt the fully extended C5 conformation in the crystal state. This intramolecularly H-bonded form is largely populated in chloroform solution in all the derivatives investigated. Conformational energy computations in vacuo support the view that the intramolecularly H-bonded C7-ring form is the most stable structure for these compounds. Only one linear derivative exhibits a (modest) anticonvulsant activity.
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277
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Crisma M, Valle G, Monaco V, Formaggio F, Toniolo C. N alpha-benzyloxycarbonyl-alpha-aminoisobutyryl-glycyl-L-isoleucyl- L-leucine methyl ester monohydrate. Acta Crystallogr C 1994; 50 ( Pt 4):563-5. [PMID: 8011270 DOI: 10.1107/s0108270193010595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
(Z)-Aib-Gly-L-Ile-L-Leu-OMe.H2O, C27H42N4O7.H2O, is a protected analogue of the C-terminal sequence of the membrane-active peptaibol antibiotic trichogin A IV. The peptide backbone is folded. The urethane carbonyl O atom acts as the acceptor of two intramolecular hydrogen bonds which give rise to a beta bend and to an alpha bend. The geometry of the latter is significantly distorted from that observed in alpha helices. This structure represents the first observation of an alpha bend in a protected tetrapeptide sequence.
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278
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Toniolo C, Formaggio F, Crisma M, Schoemaker HE, Kamphuis J. The p-bromobenzamido chromophore as a circular dichroic probe for the assignment of the screw sense of helical peptides. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/0957-4166(94)80004-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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279
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Di Blasio B, Pavone V, Saviano M, Fattorusso R, Pedone C, Benedetti E, Crisma M, Toniolo C. A second polymorph of a helical decapeptide. PEPTIDE RESEARCH 1994; 7:55-9. [PMID: 8012121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A crystal-state structural analysis of the terminally blocked apolar decapeptide pBrBz-(Aib-L-Ala)5-OMe bis-dimethylsulfoxide solvate was performed by x-ray diffraction. The peptide molecules are basically alpha-helical with five 1<--5 C = O... H-N intramolecular H bonds. Near the C terminus the regularity of the alpha-helix is disrupted in favor of the formation of intramolecular H bonds of the 1<--4 (beta-bend) and 1<--6 (pi-bend) types. Differences in conformation, solvation and association with the published structure of the tetrahydrate decapeptide polymorph are discussed.
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280
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Di Blasio B, Nastri F, Saviano M, Benedetti E, Crisma M, Toniolo C, Johnson RL. Structure of the tripeptide amide H-L-Pro-L-Leu-L-Pro-NH2, a dopamine receptor modulating agent. Acta Crystallogr C 1994. [DOI: 10.1107/s0108270193006808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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281
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Toniolo C, Pantano M, Formaggio F, Crisma M, Bonora GM, Aubry A, Bayeul D, Dautant A, Boesten WH, Schoemaker HE. Onset of the fully extended conformation in (alpha Me)Leu derivatives and short peptides. Int J Biol Macromol 1994; 16:7-14. [PMID: 8180145 DOI: 10.1016/0141-8130(94)90004-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The X-ray diffraction crystal structures of the (alpha Me)Leu derivative mClAc-D-(alpha Me) Leu-OH and the terminally protected tripeptide Z-D-(alpha Me) Leu-(L-Ala)2-OMe show the onset of the fully extended (C5) conformation for the (alpha Me) Leu residue in both independent molecules in the asymmetric unit of the former compound and in two out of the four independent molecules in the asymmetric unit of the latter compound. In addition, conformational analysis in CDCl3 solution (using FT-infra-red absorption and 1H nuclear magnetic resonance) revealed the occurrence of a significant population of fully extended conformers throughout the entire sequence of the (alpha Me) Leu homochiral homopeptides pBrBz-[D-(alpha Me) Leu]n-OtBu (from monomer to tetramer). Taken together, these results represent a clear indication that this peptide secondary structure, uncommon for protein amino acids and other C alpha-methylated chiral residues, is not a rare observation in (alpha Me) Leu derivatives and short peptides.
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282
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Crisma M, Formaggio F, Pantano M, Valle G, Bonora GM, Toniolo C, Schoemaker HE, Kamphuis J. Linear oligopeptides. Part 316. Conformational characterization of syndiotactic homo-peptides from Cα,α-disubstituted glycines. ACTA ACUST UNITED AC 1994. [DOI: 10.1039/p29940001735] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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283
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Aubry A, Bayeul D, Précigoux G, Pantano M, Formaggio F, Crisma M, Toniolo C, Boesten WHJ, Schoemaker HE, Kamphuis J. Position of side-chain branching and handedness of turns and helices of homopeptides from chiral Cα-methylated amino acids. Crystal-state structural analysis of (αMe)Leu trimer and tetramer. ACTA ACUST UNITED AC 1994. [DOI: 10.1039/p29940000525] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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284
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Valle G, Formaggio F, Crisma M, Toniolo C, Kamphuis J. Structure of (Z)-L-Pro-D-(αMe)Phe-OH. Acta Crystallogr C 1993. [DOI: 10.1107/s0108270193004457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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285
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Bardi R, Piazzesi ΑM, Crisma M, Toniolo C, Kishore R. Crystal structure of N β-tert-butyloxycarbonyl-β- alanyl-L-alanine methylamide, C 12H 23N 3O 4. Z KRIST-CRYST MATER 1993. [DOI: 10.1524/zkri.1993.207.12.290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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286
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Pantano M, Formaggio F, Crisma M, Toniolo C, Schoemaker ΗE, Boesten WHJ, Kamphuis J. Crystal structure of N α-formyl-glycyl-L-(β-tertbutyloxy) aspartyl-L-C α-methyl-phenylalanine methylester, C 22H 31N 3O 7. Z KRIST-CRYST MATER 1993. [DOI: 10.1524/zkri.1993.207.12.287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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287
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Fabiano N, Valle G, Crisma M, Toniolo C, Saviano M, Lombardi A, Isernia C, Pavone V, Di Blasio B, Pedone C. Conformational versatility of the N alpha-acylated tripeptide amide tail of oxytocin. Synthesis and crystallographic characterization of three C2 alpha-backbone modified, conformationally restricted analogues. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1993; 42:459-65. [PMID: 8106198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The synthesis, physical and analytical characterization, and crystal-state structural analysis by X-ray diffraction of three analogues of the N alpha-acylated tripeptide amide tail of oxytocin, each containing a cyclic C alpha, alpha-disubstituted glycine at position 2, have been performed. The peptides are Boc-L-Pro-Ac3c-Gly-NH2, Z-L-Pro-Ac5c-Gly-NH2 and Z-L-Pro-Ac6c-Gly-NH2. While the former is folded in a type-II beta-turn conformation at the -L-Pro-Ac3c- sequence, the two latter tripeptides form two consecutive (type-II, type-I') beta-turns. The Ac5c- and Ac6c-tripeptides are the first examples of such a highly folded structural combination in a position-2 analogue of the N alpha-acylated -L-Pro-L-Leu-Gly-NH2 sequence.
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288
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Piazzesi AM, Bardi R, Crisma M, Toniolo C, Singh M, Chauhan VS. Molecular and crystal structure of a dehydroalanine dipeptide. Z KRIST-CRYST MATER 1993. [DOI: 10.1524/zkri.1993.207.12.25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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289
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Valle G, Crisma M, Toniolo C. Crystal structure of N α-para-bromobenzoyl-C α.α- diphenylglycyl-glycyl-glycine tert-butylester, C 29H 30N 3O 5Br. Z KRIST-CRYST MATER 1993. [DOI: 10.1524/zkri.1993.207.12.293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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290
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Crisma M, Moretto V, Valle G, Formaggio F, Toniolo C. First characterization at atomic resolution of the C-activating groups in a peptide synthesis acid chloride, acid azide and carboxylic-carboxylic mixed anhydride. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1993; 42:378-83. [PMID: 8244633 DOI: 10.1111/j.1399-3011.1993.tb00508.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The X-ray diffraction structures of three N alpha-protected, C alpha-activated MeAib derivatives are reported. They are Tos-MeAib-Cl, Tos-MeAib-N3 and Tos-MeAib-O-Piv. The geometry and conformation of these classical carboxyl activating groups, which have been characterized at atomic resolution for the first time, are discussed.
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291
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Toniolo C, Crisma M, Formaggio F, Valle G, Cavicchioni G, Precigoux G, Aubry A, Kamphuis J. Structures of peptides from alpha-amino acids methylated at the alpha-carbon. Biopolymers 1993; 33:1061-72. [PMID: 8343585 DOI: 10.1002/bip.360330708] [Citation(s) in RCA: 211] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The structural preferences of peptides (and depsipeptides) from the achiral MeAib and Hib residues, and the chiral Iva, (alpha Me) Val, (alpha Me) Leu, and (alpha Me) Phe residues, as determined by conformational energy computations, x-ray diffraction analyses, and 1H-nmr and spectroscopic studies, are reviewed and compared with literature data on Aib-containing peptides. The results obtained indicate that helical structures are preferentially adopted by peptides rich in these alpha-amino acids methylated at the alpha-carbon. Intriguing experimental findings on the impact of the chirality of Iva, (alpha Me) Val, and (alpha Me) Phe residues on helix screw sense are illustrated.
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292
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Pantano M, Formaggio F, Crisma M, Bonora GM, Toniolo C, Aubry A, Bayeul D, Dautant A, Précigoux G, Boesten WH. Synthesis and conformational analysis of (alpha Me)Leu/Aib model peptides. PEPTIDE RESEARCH 1993; 6:196-204. [PMID: 8400615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We have synthesized by solution methods and fully characterized a variety of (alpha Me)Leu/Aib model peptides to the octapeptide level. A solution conformational analysis was performed by using infrared absorption. 1H nuclear magnetic resonance, and circular dichroism. The crystal-state structures of Z-D-(alpha Me)Leu-(Aib)2-OtBu, pBrBz-(Aib)2-D-(alpha Me)Leu-(Aib)2-OtBu, and Ac-(Aib)2-D-(alpha Me)Leu-(Aib)2-OtBu monohydrate were solved by x-ray diffraction. The results indicate that the (alpha Me)Leu residue may be easily incorporated into beta-bends and 3(10)-helical structures, and suggest that this residue tends to induce a helix handedness opposite to that promoted by its unmethylated counterpart (Leu) of the same optical configuration.
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293
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Crisma M, Valle G, Bonora GM, Toniolo C, Cavicchioni G. The beta-bend ribbon spiral. Synthesis and conformational analysis in solution and in the crystal state of depsipeptides containing alpha-hydroxyisobutyric acid. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1993; 41:553-60. [PMID: 8349413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The synthesis and conformational analysis in solution (by FTIR absorption and 1H NMR) and in the crystal state (by X-ray diffraction) of three Hib-containing depsipeptides have been performed. In the crystal state Z-Aib-Hib-Aib-OMe is folded into a type-III beta-bend, while the conformation adopted by Z-Aib-Hib)2-Aib-OMe is a beta-bend ribbon spiral, characterized by two type-III beta-bends with Aib(1)-Hib(2) and Aib(3)-Hib(4) as corner residues, respectively. Both independent molecules in the asymmetric unit of t-Boc-L-Ala-Hib-L-Ala-OMe crystals are folded into a type-II beta-bend. For the Aib-Hib depsipeptides the conformation adopted in the crystal state is also that largely prevailing in solution, whereas for t-Boc-L-Ala-Hib-L-Ala-OMe the beta-bend conformation is significantly less populated in solution. A comparison is also made with: (i) the published crystal-state conformations of fully protected -(Aib)3-, -(Aib)5-, and -L-Ala-Aib-L-Ala- sequences and the beta-bend ribbon spiral generated by (Aib-L-Pro)n oligomers, and (ii) with the herewith described solution preferred conformation of Z-L-Ala-Aib-L-Ala-OMe. The possible use of Hib as an isosteric replacement for Aib in the design of conformationally constrained depsipeptides is briefly discussed.
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294
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Formaggio F, Pantano M, Crisma M, Toniolo C, Boesten W, Schoemaker H, Kamphuis J, Becker E. Backbone modified formyl-methionyl tripeptide chemoattractants. Bioorg Med Chem Lett 1993. [DOI: 10.1016/s0960-894x(00)80699-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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295
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Formaggio F, Pegoraro S, Crisma M, Valle G, Toniolo C, Précigoux G, Boesten WH, Schoemaker HE, Kamphuis J. Reverse relationship between alpha-carbon chirality and helix handedness in (alpha Me)Phe peptides. J Biomol Struct Dyn 1993; 10:919-31. [PMID: 8318165 DOI: 10.1080/07391102.1993.10508684] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The crystal-state preferred conformations of two tripeptides, one tetrapeptide, and one pentapeptide, each containing a single residue of the chiral, C alpha, alpha-disubstituted glycine C alpha-methyl, C alpha-benzylglycine [(alpha Me)Phe], have been determined by X-ray diffraction. The tripeptides are Z-L-(alpha Me)Phe-(Aib)2-OH dihydrate and Z-Aib-D-(alpha Me)Phe-Aib-OtBu, the tetrapeptide is Z-(Aib)2-D-(alpha Me)Phe-Aib-OtBu, and the pentapeptide is pBrBz-(Aib)2-DL-(alpha Me)Phe-(Aib)2-OtBu. While the two tripeptides are folded in a beta-bend conformation, two such conformations are consecutively formed by the tetrapeptide. The pentapeptide adopts a regular 3(10)-helix promoted by three consecutive beta-bends. This study confirms the strong propensity of short peptides containing C alpha-methylated alpha-aminoacids to fold into beta-bends and 3(10)-helical structures. Since Aib is achiral, the handedness of the observed bends and helices is dictated by the presence of the (alpha Me)Phe residue. In general, we have found that the relationship between (alpha Me)Phe chirality and helix handedness is opposite to that exhibited by protein aminoacids. A comparison with the preferred conformation of other extensively investigated C alpha-methylated aminoacids is made.
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296
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Valle G, Formaggio F, Crisma M, Toniolo C, Kamphuis J. Structure of Z-L-(αMe)Phe-(L-Ala)2-OMe monohydrate. Acta Crystallogr C 1993. [DOI: 10.1107/s0108270192010023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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297
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Crisma M, Valle G, Formaggio F, Bianco A, Toniolo C. Helical screw sense of peptide molecules. X-Ray diffraction structures of two oligopeptides with a single chiral centre. ACTA ACUST UNITED AC 1993. [DOI: 10.1039/p29930000987] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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298
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Morelle N, Gharbi-Benarous J, Acher F, Valle G, Crisma M, Toniolo C, Azerad R, Girault JP. Conformational analysis of cyclohexane-derived analogues of glutamic acid by X-ray crystallography, NMR spectroscopy in solution, and molecular dynamics. ACTA ACUST UNITED AC 1993. [DOI: 10.1039/p29930000525] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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299
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Bardi R, Piazzesi ΑM, Crisma M, Toniolo C, Balaram P, Sukumar M. Crystal structure of N-tert-butyloxycarbonyl-(S)- pipecolyl-α-aminoisobutyric acid, C 15Η 26Ν 2O 5. Z KRIST-CRYST MATER 1992. [DOI: 10.1524/zkri.1992.202.14.171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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300
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Piazzesi AM, Bardi R, Pantano M, Formaggio F, Crisma M, Toniolo C. Molecular and crystal structure of a terminally-blocked Aib homotetrapeptide. Z KRIST-CRYST MATER 1992. [DOI: 10.1524/zkri.1992.200.14.83] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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