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Kijewska M, Wołczański G, Kosson P, Wieczorek R, Lisowski M, Stefanowicz P. Stapling of leu-enkephalin analogs with bifunctional reagents for prolonged analgesic activity. Chem Commun (Camb) 2024; 60:3023-3026. [PMID: 38356394 DOI: 10.1039/d3cc06345c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
The design and synthesis of leu-enkephalin analogs by replacing the glycine residues with N-(2-thioethyl)glycines and opening the cyclisation potential is presented. The cyclization (stapling) was achieved using bifunctional reagents (hexafluorobenzene and trithiocyanuric acid derivatives). The CD conformational studies of the stapled analogs suggest that the peptides adopt the type I β-turn conformation, which is in agreement with the theoretical analysis. The analog containing a trithiocyanuric acid derivative with a benzyl substituent shows potent analgesic activity.
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Affiliation(s)
- Monika Kijewska
- Faculty of Chemistry, University of Wrocław, Joliot-Curie 14, 50-383 Wrocław, Poland.
| | - Grzegorz Wołczański
- Faculty of Chemistry, University of Wrocław, Joliot-Curie 14, 50-383 Wrocław, Poland.
| | - Piotr Kosson
- Mossakowski Medical Research Institute, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106 Warszawa, Poland
| | - Robert Wieczorek
- Faculty of Chemistry, University of Wrocław, Joliot-Curie 14, 50-383 Wrocław, Poland.
| | - Marek Lisowski
- Faculty of Chemistry, University of Wrocław, Joliot-Curie 14, 50-383 Wrocław, Poland.
| | - Piotr Stefanowicz
- Faculty of Chemistry, University of Wrocław, Joliot-Curie 14, 50-383 Wrocław, Poland.
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2
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Park HS, Byun BJ, Kang YK. Exploring Conformational Preferences of Leu-enkephalin Using the Conformational Search and Double-Hybrid DFT Energy Calculations. ACS OMEGA 2022; 7:27755-27768. [PMID: 35967045 PMCID: PMC9366962 DOI: 10.1021/acsomega.2c03942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
The conformational preferences of Leu-enkephalin (Leu-Enk) were explored by the conformational search and density functional theory (DFT) calculations. By a combination of low-energy conformers of each residue, the initial structures of the neutral Leu-Enk were generated and optimized using the ECEPP3 force field in the gas phase. These structures were reoptimized at the HF/3-21G(d) and M06-2X levels of theory with 6-31G(d) and 6-31+G(d) basis functions. We finally located the 139 structures with the relative energy <10 kcal mol-1 in the gas phase, from which the structures of the corresponding zwitterionic Leu-Enk were generated and reoptimized at the M06-2X/6-31+G(d) level of theory using the implicit solvation model based on density (SMD) in water. The conformational preferences of Leu-Enk were analyzed using Gibbs free energies corrected by single-point energies calculated at the double-hybrid DSD-PBEP86-D3BJ/def2-TZVP level of theory in the gas phase and in water. The neutral Leu-Enk dominantly adopted a folded structure in the gas phase stabilized by three H-bonds with a βII'-bend-like motif at the Gly3-Phe4 sequence and a close contact between the side chains of Phe4 and Leu5. The zwitterionic Leu-Enk exhibited a folded structure in water stabilized by three H-bonds with double β-bends such as a βII' bend at the Gly2-Gly3 sequence and a βI bend at the Gly3-Phe4 sequence. The calculated ensemble-averaged distance between CGly2 α and CLeu5 α of the zwitterionic Leu-Enk in water is consistent with the value estimated from the simulated annealing using the distance constraints derived from nuclear Overhauser effect spectroscopy (NOESY) spectra in water. Interestingly, the preferred conformations of the neutral and zwitterionic Leu-Enk are new folded structures not predicted by earlier computational studies. According to the refined model of the zwitterionic Leu-Enk bound to δ-opioid receptor (δOR), there were favorable interactions of the terminal charged groups of Leu-Enk with the side chains of charged residues of δOR as well as a favorable CAryl···H interaction of the Phe4 residue of Leu-Enk with Trp284 of δOR. Hence, these favorable interactions would induce the folded structure of the zwitterionic Leu-Enk with double β-bends isolated in water into the "bioactive conformation" like an extended structure when binding to δOR.
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Affiliation(s)
- Hae Sook Park
- Department
of Nursing, Cheju Halla University, 38 Halladaehak-ro, Jeju, Jeju-do 63092, Republic of Korea
| | - Byung Jin Byun
- Drug
Discovery Center, JW Pharmaceutical Co.
Ltd., 2477 Nambusunhwan-ro, Seocho-gu, Seoul 06725, Republic
of Korea
| | - Young Kee Kang
- Department
of Chemistry, Chungbuk National University, 1 Chungdae-ro,
Seowon-gu, Cheongju, Chungbuk 28644, Republic of Korea
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3
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Lameiras P, Nuzillard JM. Tailoring the nuclear Overhauser effect for the study of small and medium-sized molecules by solvent viscosity manipulation. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2021; 123:1-50. [PMID: 34078536 DOI: 10.1016/j.pnmrs.2020.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 11/06/2020] [Accepted: 12/02/2020] [Indexed: 06/12/2023]
Abstract
The nuclear Overhauser effect (NOE) is a consequence of cross-relaxation between nuclear spins mediated by dipolar coupling. Its sensitivity to internuclear distances has made it an increasingly important tool for the determination of through-space atom proximity relationships within molecules of sizes ranging from the smallest systems to large biopolymers. With the support of sophisticated FT-NMR techniques, the NOE plays an essential role in structure elucidation, conformational and dynamic investigations in liquid-state NMR. The efficiency of magnetization transfer by the NOE depends on the molecular rotational correlation time, whose value depends on solution viscosity. The magnitude of the NOE between 1H nuclei varies from +50% when molecular tumbling is fast to -100% when it is slow, the latter case corresponding to the spin diffusion limit. In an intermediate tumbling regime, the NOE may be vanishingly small. Increasing the viscosity of the solution increases the motional correlation time, and as a result, otherwise unobservable NOEs may be revealed and brought close to the spin diffusion limit. The goal of this review is to report the resolution of structural problems that benefited from the manipulation of the negative NOE by means of viscous solvents, including examples of molecular structure determination, conformation elucidation and mixture analysis (the ViscY method).
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Affiliation(s)
- Pedro Lameiras
- Université de Reims Champagne-Ardenne, CNRS, ICMR UMR 7312, 51097 Reims, France
| | - Jean-Marc Nuzillard
- Université de Reims Champagne-Ardenne, CNRS, ICMR UMR 7312, 51097 Reims, France
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4
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Ameziane Hassani C, Houssat M, Hazm JE. Theoretical conformational analysis of opiate peptides Leu-Enkephalin (H-Tyr-Gly-Gly-Phe-Leu-OH) and its two thioamide analogs (H-Tyr-Glyψ[CSNH]Gly-Phe-Leu-OH) and (H-Tyr-Gly-Glyψ[CSNH]Phe-Leu-OH). Struct Chem 2017. [DOI: 10.1007/s11224-017-1045-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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5
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D'ALAGNI MARIA, GULLÁ PATRIZIA, RODA LGIORGIO, ROSCETTI GIANNA. In vitvo interactions of opioid peptides with phospholipids. ACTA ACUST UNITED AC 2009. [DOI: 10.1111/j.1399-3011.1990.tb00057.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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6
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KESSLER HORST, HÖLZEMANN GÜNTER, ZECHEL CHRISTIAN. Peptide conformations. 33. Conformational analysis of cyclic enkephalin analogs of the type Tyr-cyclo-(-N ω -Xxx-Gly-Phe-Leu-)*. ACTA ACUST UNITED AC 2009. [DOI: 10.1111/j.1399-3011.1985.tb02174.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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7
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HAN SHAWLIN, STIMSON EVELYNR, MAXFIELD FREDERICKR, SCHERAGA HAROLDA. CONFORMATIONALSTUDY OF [LEU5]-ENKEPHALIN BY LASER RAMAN SPECTROSCOPY. ACTA ACUST UNITED AC 2009. [DOI: 10.1111/j.1399-3011.1980.tb02950.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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8
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GARBAY-JAUREGUIBERRY C, MARION D, FELLION E, ROQUES B. Refinement of conformational preferences of Leu enkephalin and Tyr-Gly-Gly-Phe by 15 N n.m.r. ACTA ACUST UNITED AC 2009. [DOI: 10.1111/j.1399-3011.1982.tb03066.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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9
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Gu X, Ying J, Min B, Cain JP, Davis P, Willey P, Navratilova E, Yamamura HI, Porreca F, Hruby VJ. Parallel synthesis and biological evaluation of different sizes of bicyclo[2,3]-Leu-enkephalin analogues. Biopolymers 2005; 80:151-63. [PMID: 15660379 DOI: 10.1002/bip.20208] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Parallel synthesis of peptides and peptidomimetics has been an important approach to search for biologically active ligands. A novel systematic synthesis of different size bicyclic dipeptide mimetics was developed on solid-phase supports. By taking advantage of the enantioselective synthesis of omega-unsaturated amino acids and their N-methylated derivatives, the hemiaminal problem was prevented in the pathway to thiazolidine formation. The bicyclic dipeptide was generated on the solid-phase support in three steps by an unconventional method. By inserting this bicyclic scaffold into the synthesis of a larger bioactive peptide, 11 different sizes of bicyclo[2,3]-Leu-enkephalin analogues were synthesized in a fast and efficient way. Modeling studies show that a reversed turn structure at positions 2-3 was favored when an L- and L-bicyclic scaffold was used, and that an extended conformation at the N-terminal was favored when a D- and L-bicyclic scaffold was inserted. Binding affinities and bioassay studies show ligands with micromolar binding affinities and antagonist bioactivities for the [6,5]- and [7,5]-bicyclo-Leu-enkephalin analogues.
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Affiliation(s)
- Xuyuan Gu
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, USA
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10
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Tyndall JDA, Pfeiffer B, Abbenante G, Fairlie DP. Over One Hundred Peptide-Activated G Protein-Coupled Receptors Recognize Ligands with Turn Structure. Chem Rev 2005; 105:793-826. [PMID: 15755077 DOI: 10.1021/cr040689g] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Joel D A Tyndall
- Center for Drug Design and Development, Institute for Molecular Bioscience, University of Queensland, Brisbane, Qld 4072, Australia
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11
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Eguchi M, Shen RYW, Shea JP, Lee MS, Kahn M. Design, synthesis, and evaluation of opioid analogues with non-peptidic beta-turn scaffold: enkephalin and endomorphin mimetics. J Med Chem 2002; 45:1395-8. [PMID: 11906279 DOI: 10.1021/jm0155897] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have identified a mu-selective opioid receptor agonist without a cationic amino group in the molecule from libraries of bicyclic beta-turn peptidomimetics. The biologically active conformation of the lead is proposed to mimic an endomorphin type III 4 --> 1 beta-turn conformation.
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12
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Doi M, Ishida T, Inoue M, Fujiwara T, Tomita KI, Kimura T, Sakakibara S. Three-dimensional structure of monoanionic methionine-enkephalin: X-ray structure of tert
-butyloxycarbonyl-Tyr-Gly-Gly-(4-bromo)Phe-Met-OH. FEBS Lett 2001. [DOI: 10.1016/0014-5793(84)81318-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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13
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Gosselin F, Tourwé D, Ceusters M, Meert T, Heylen L, Jurzak M, Lubell WD. Probing opioid receptor-ligand interactions by employment of indolizidin-9-one amino acid as a constrained Gly(2)-Gly(3) surrogate in a leucine-enkephalin mimic. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 2001; 57:337-44. [PMID: 11328491 DOI: 10.1046/j.1397-002x.2000.00812.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The relationship between the conformation and biological activity of Leu-enkephalin was studied using (2S,6R,8S)-9-oxo-8-N-(Boc)amino-1-azabicyclo[4.3.0]nonane-2-carboxylic acid [(2S,6R,8S)-1, I(9)AA] as a constrained Gly(2)-Gly(3) dipeptide surrogate. [I(9)AA](2,3)-Leu-enkephalin 12 was assembled using solid-phase peptide synthesis on Merrifield resin with TBTU as the coupling reagent. The in vitro assays indicated that [I(9)AA](2,3)-Leu-enkephalin 12 exhibited affinities for the mu- and delta-opioid receptors that were three orders of magnitude lower than that of Leu-enkephalin, as well as partial agonist character for both receptors. In in vivo assays for spinal analgesia, the indolizidinone analog 12 showed significantly enhanced duration of action, indicating an increased metabolic stability. Conformational analysis was performed using NMR and CD spectroscopy. The amide temperature coefficients and 3J(NH-CalphaH) coupling constants for 12 could not support a hydrogen-bonded beta-turn structure; however, its CD spectrum indicated a turn conformation. Incorporation of indolizidinone amino acid 1 into Leu-enkephalin thus provided additional support for the importance of a turn conformation for the biological activity of the native peptide.
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Affiliation(s)
- F Gosselin
- Département de chimie, Université de Montréal, C. P. 6128, Succursale Center Ville, Montréal, Québec, Canada
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14
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Carpino LA, Philbin M. Amino-Protecting Groups Subject to Deblocking under Conditions of Nucleophilic Addition to a Michael Acceptor. Structure−Reactivity Studies and Use of the 2-(tert-Butylsulfonyl)-2-propenyloxycarbonyl (Bspoc) Group. J Org Chem 1999. [DOI: 10.1021/jo982141d] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Louis A. Carpino
- Department of Chemistry, Box 34510, University of Massachusetts, Amherst, Massachusetts 01003-4510
| | - Michael Philbin
- Department of Chemistry, Box 34510, University of Massachusetts, Amherst, Massachusetts 01003-4510
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15
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Abstract
The structure of Leu-enkephalin (L-Enk) and Met-enkephalin (M-Enk) have frequently been studied, in particular by nuclear magnetic resonance spectroscopy. After more than 20 years of research, it was concluded that enkephalins have no preferred structure in aqueous solution, but that they may have in other solvents. We have performed molecular dynamics simulations of zwitterionic L-Enk in water, and zwitterionic as well as neutral L-Enk dimethyl sulfoxide (DMSO). In water the peptide is very flexible, although there seems to be a preference for compact conformations. In DMSO, the peptide forms a clear salt bridge in the zwitterionic form, but has no preferred conformation in the neutral form. This difference in conformation may provide an explanation for measurements in DMSO in which multiple conformations were found to exist. In this paper we introduce a new formulation for a dihedral angle autocorrelation function, and apply it to study side-chain dynamics in L-Enk. We find that the side-chain dynamics of the large Tyr and Phe residues cannot be adequately sampled in 2.0-ns simulations, while this does seem to be possible for the smaller Leu side chain.
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Affiliation(s)
- D van der Spoel
- Bioson Research Institute, University of Groningen, The Netherlands
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16
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Guis C, Bruetschy L, Meudal H, Roques BP, Gacel GA. Investigation of the structural parameters involved in the delta-opioid selectivity of several families of opioid peptides. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1993; 41:576-86. [PMID: 8394291 DOI: 10.1111/j.1399-3011.1993.tb00480.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: 01/30/2023]
Abstract
Three series of highly delta-opioid selective peptides are now available, and each family is used as template to investigate the structural parameters involved in delta-receptor recognition and in the modulation of the selectivity of the parent peptide. The first series includes cyclic derivatives such as Tyr-D-Pen-Gly-Phe-D-Pen(DPDPE) and Tyr-D-Pen-Gly-Phe-Pen(DPLPE); the second are the synthetic linear constrained peptides [Tyr-D-Ser(OtBu)-Gly-Phe-Leu-Thr(DSTBULET), Tyr-D-Ser(OtBu)-Gly-Phe-Leu-Thr (OtBu)(BUBU) and especially Tyr-D-Cys(StBu)-Gly-Phe-Leu-Thr(OtBu) (BUBUC)] and the last one the natural peptides [Tyr-D-Met-Phe-His-Leu-Met-Asp-NH2 (deltorphin or dermenkephalin) and Tyr-D-Ala-Phe-Asp-Val-Val-GlyNH2 ([D-Ala2] deltorphin I)]. In the present study, the possibly of transposing some of the decisive factors of delta-selectivity evidenced in the two other families, to the linear constrained peptides series was examined. With this aim in view, residues such as Phe3, pClPhe4 or Asp were introduced in the sequence of DSTBULET, BUBU or BUBUC. Direct comparison between the biochemical profiles of the [pClPhe4] analogs of the linear constrained peptides and their parent compounds shows that the addition of an electronegative atom on the Phe4 residue of enkephalin sequences is not an absolute parameter for delta-selectivity improvement. The hydrophobic delta-receptor subsite seems able to receive a range of molecular volumes and electronegativities. By contrast, this subsite cannot interact with a Phe3 aromatic ring introduced in this series of peptides. Moreover, the results obtained with linear peptides including additional negatively charged residues demonstrate that the proposed location of the delta-receptors in a cationic membrane environment is not adequate to explain the selectivity profile of a number of compounds.
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Affiliation(s)
- C Guis
- Department of Molecular and Structural Pharmacochemistry, U266 INSERM-URAD 1500 CNRS, René Descartes University, Paris, France
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17
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Penkler LJ, Van Rooyen PH, Wessels PL. Conformational analysis of mu-selective [D-Ala2,MePhe4]enkephalins. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1993; 41:261-74. [PMID: 8385078 DOI: 10.1111/j.1399-3011.1993.tb00334.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The conformational space of the potent mu-selective opioids [D-Ala2,MePhe4,Gly-ol5]enkephalin (DAGO) and [D-Ala2,MePhe4,Met(O)-ol5]enkephalin (FK 33-824) has been analyzed by 1H-NMR spectroscopy and theoretical calculations involving systematic conformational searching and energy minimizations. A cis-trans equilibrium of the Gly3-MePhe4 amide bond is induced by the N-methyl group, and the more energetically favoured trans isomer is proposed as the biologically relevant form. A compact interaction between the side chains of Tyr1 and D-Ala2 was demonstrated by NOE and ROE effects in both peptides in D2O and DMSO-d6, further supported by shielding of the D-Ala2 methyl protons in both solvents. Analysis of coupling constants, NOE and ROE data indicated significant restriction of the conformational freedom of the MePhe4 side-chain for both peptides in the two solvents. The NMR results and theoretical calculations point towards folded low energy conformations characterized by a beta II-type turn around Gly3-MePhe4. For the trans isomer, a Tyr1-MePhe4 phenyl ring separation between 8.5 and 12.5 A was accompanied by proximity between the D-Ala2 side chain and the C-terminal in low energy conformations. The results are in good agreement with available data on related active enkephalins. The conformational effects induced by simultaneous incorporation of D-Ala2 and MePhe4 in enkephalins is discussed in the light of the enhanced mu-opioid receptor selectivity and activity of these peptides.
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Affiliation(s)
- L J Penkler
- Department of Chemistry, University of Pretoria, South Africa
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18
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Sivanandaiah KM, Babu VV, Renukeshwar C. Fmoc-amino acid chlorides in solid phase synthesis of opioid peptides. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1992; 39:201-6. [PMID: 1399258 DOI: 10.1111/j.1399-3011.1992.tb00789.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: 12/26/2022]
Abstract
Fmoc-amino acid chlorides were employed in the solid phase synthesis of the opioid peptides [Leu]enkephalin, [Leu]enkephalin amide, and dermorphin. The conventional polystyrene-based Merrifield resin or Wang's resin served as solid support. A binary salt of either triethylamine or diisopropylethylamine in the presence of 1-hydroxybenzotriazole or pivalic acid was used for acylation. The coupling rates were quite fast, being comparatively faster when 1-hydroxybenzotriazole was used along with triethylamine or diisopropylethylamine. The peptides obtained in good yields showed, after purification, biological and spectral properties identical with those of the natural peptides.
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Affiliation(s)
- K M Sivanandaiah
- Department of Studies in Chemistry, Central College, Bangalore University, India
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19
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20
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Demetropoulos IN, Gresh N. A supermolecule study of the effect of hydration on the conformational behaviour of leucine-enkephalin. J Comput Aided Mol Des 1991; 5:81-94. [PMID: 1869900 DOI: 10.1007/bf00129748] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A theoretical conformational study was performed on leu-enkephalin in its zwitterionic form, both in vacuo and in the presence of a number, n, of up to 13 water molecules saturating its first hydration shell. The intramolecular energy of enkephalin as well as the intermolecular enkephalin-water and water-water interaction energies were computed with the SIBFA procedure (Sum of Interactions Between Fragments Ab initio computed), which uses additive ab initio multipole systematics and analytical formulas grounded on ab initio SCF computations. Energy minimizations were performed with a polyvalent minimizer, Merlin, with which three distinct derivative and three distinct nonderivative minimizers can be activated in a sequential fashion. Eight different candidate conformations of enkephalin were used as starting points. These conformations are either those found in distinct X-ray structures, or those proposed on the basis of theoretical computations by other authors. In the absence of hydration, they converged towards distinct folded energy-minima, the best four ones being separated by an energy gap of 8.7 kcal/mol. In marked contrast, with up to n = 13, the energetical separation between the six best conformers narrowed down to congruent to 4 kcal/mol. They can be characterized by: (a) either a direct or a water-mediated ammonium-carboxylate interaction; b) either a close proximity (as in morphine) or a large separation between the aromatic rings of Tyr and Phe (intercenter separations of congruent to 4.5 A and congruent to 10.5 A, respectively), with each of the four mutual combinations of (a) and (b) being represented.
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21
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Picone D, D'Ursi A, Motta A, Tancredi T, Temussi PA. Conformational preferences of [Leu5]enkephalin in biomimetic media. Investigation by 1H NMR. EUROPEAN JOURNAL OF BIOCHEMISTRY 1990; 192:433-9. [PMID: 2209598 DOI: 10.1111/j.1432-1033.1990.tb19245.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The conformation of [Leu5]enkephalin has been studied by 1H-NMR spectroscopy in media more like the actual environment in which the agonist-receptor interaction takes place than water, i.e. in three cryoprotective mixtures (dimethylformamide/water, methanol/water and ethylene glycol/water), in aqueous SDS and in two neat solvents, dimethylformamide and acetonitrile, whose dielectric constants (36.7 and 37.5) are intermediate between that of water and that of the lipid phase. In all cases examined, contrary to the studies in water or dimethylsulfoxide, we were able to detect numerous nuclear Overhauser effects, indicating that the media employed favour well-defined structures and/or reduce the internal motions of the peptide. Data from both organic solvents and cryoprotective mixtures suggest a 4----1 beta turn as the most probable structure of [Leu5]enkephalin in solution, whereas in SDS/H2O micelles the structural picture appears completely different, suggesting the presence of a 5----2 beta turn. The existence of two different preferred conformations of enkephalins may possibly be related to their ability to be effective towards both mu and delta opioid receptors.
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Affiliation(s)
- D Picone
- Dipartimento di Chimica, Università di Napoli Federico II, Italy
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22
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Karayannis T, Gerothanassis IP, Sakarellos-Daitsiotis M, Sakarellos C, Marraud M. 17O- and 14N-NMR studies of Leu-enkephalin and enkephalin-related fragments in aqueous solution. Biopolymers 1990; 29:423-39. [PMID: 2331506 DOI: 10.1002/bip.360290213] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
17O- and 14N-nmr chemical shifts and line widths of the carboxyl and amino terminal groups of Leu-enkephalin--Tyr-Gly-Gly-Phe-[17O]Leu-Oh--and enkephalin-related fragments--[17O]Leu-OH, Phe-[17O]Leu-OH, Gly-Phe-[17O]Leu-OH, and Gly-Gly-Phe-[17O]Leu-OH--were measured in aqueous solution over the entire H pH range. Enrichment in 17O was achieved by saponification of the corresponding O-methyl esters. Ionization constants and titration shifts were obtained by nonlinear least-squares fits to one-proton titration curves. [17O]Leu-OH exhibits a profound pH-dependent solvation change on deprotonation of the carboxyl group, as shown by 17O- and 14N-nmr line widths. In contrast, the peptides studied do not exhibit pH-dependent conformational (solvation) changes on deprotonation of the carboxyl group, and a head-to-tail intramolecular association between the ionic terminal groups should be excluded. It is shown that the peptides do not exhibit isotropic overall molecular motion and that segmental motion rather than fast internal motion influences the effective correlation times at the sites of the carboxyl oxygens and the amino nitrogen.
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Affiliation(s)
- T Karayannis
- Department of Chemistry, University of Ioannina, Greece
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23
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Vesterman B, Saulitis J, Betins J, Liepins E, Nikiforovich GV. Dynamic space structure of the Leu-enkephalin molecule in DMSO solution. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 998:204-9. [PMID: 2790063 DOI: 10.1016/0167-4838(89)90274-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The dynamical space structure of the Leu-enkephalin molecule in DMSO solution was described combining the ROE measurements and Monte Carlo energy calculations. The statistical weights for possible Leu-enkephalin conformers were estimated by comparing the NMR-experimental parameters and the same parameters average over statistical samples of molecular structures obtained by Monte Carlo techniques for every low-energy conformer. The statistical weight estimations reveal that the Leu-enkephalin molecule in DMSO solution is apparently represented by a mixture of at least two peptide backbone conformers with the mean statistical weight values of 70% and 30%. Both conformers possess significant local conformational fluctuations. Each of them represents a folded backbone structure with the folding at the Gly2-Gly3 and Gly3-Phe4 fragments occurring simultaneously in solution.
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Affiliation(s)
- B Vesterman
- Institute of Organic Synthesis, Latvian S.S.R. Academy of Science, Riga, USSR
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24
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Temussi PA, Picone D, Castiglione-Morelli MA, Motta A, Tancredi T. Bioactive conformation of linear peptides in solution: an elusive goal? Biopolymers 1989; 28:91-107. [PMID: 2541825 DOI: 10.1002/bip.360280112] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Bioactive peptides of natural origin have, in general, short linear sequences, and are characterized by a large conformational flexibility. It is very difficult to study their conformation in solution since they exist, almost invariably, as a complex mixture of numerous conformers, most of which are extended. The so-called bioactive conformation may be one of them, although the solvents used in solution studies often have properties drastically different from those of the biological system in which the peptide acts. There is, however, no simple way of identifying the bioactive conformation amid the many existing conformers. It is possible to approach a solution to this problem using two distinct strategies: (a) Limiting the conformational freedom of the peptide, e.g., by increasing the viscosity of the solution and decreasing the temperature, in the assumption that the bioactive conformation is, even slightly, more stable than the others. (b) Trying to mimic in solution the physicochemical features of the more reliable receptor models. These two approaches will be illustrated with examples taken mainly from opioid peptides.
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25
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Opioid Receptors and their Ligands: Recent Developments. ACTA ACUST UNITED AC 1989. [DOI: 10.1016/b978-0-12-013318-5.50008-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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26
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Dhingra MM, Saran A. Comparative study of conformational behaviour of leucine and methionine enkephalinamides by1H-nuclear magnetic resonance spectroscopy. J Biosci 1988. [DOI: 10.1007/bf02832207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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27
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Motta A, Picone D, Tancredi T, Temussi P. Low temperature nmr studies of leu-enkephalins in cryoprotective solvents. Tetrahedron 1988. [DOI: 10.1016/s0040-4020(01)86128-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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28
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Olatunji OL, Premilat S. Solvent dependent conformational statistics of enkephalin and angiotensin II. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1987; 29:1-8. [PMID: 3570649 DOI: 10.1111/j.1399-3011.1987.tb02224.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A screened electrostatic potential model of hydration, recently proposed, is used to simulate the statistical behaviour of enkephalin and angiotensin II in solution. Curves of the end-to-end distances as well as calculated values of n.m.r. coupling constants are given and compared with experiments and results obtained from other theoretical studies. The satisfactory agreement between calculated values and the corresponding experimental data indicates that the present theoretical approach is a simple and efficient way to take into account solvent effects on the conformation of biological molecules.
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29
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Hérion P, De Coen JL. Production and characterization of a rat monoclonal antibody against leu5 enkephalin. Mol Immunol 1986; 23:209-15. [PMID: 3702876 DOI: 10.1016/0161-5890(86)90044-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A rat X mouse hybridoma line producing a monoclonal antibody against leu5 enkephalin has been obtained. The monoclonal antibody belongs to the IgG2b class and has an affinity constant of 8.0 X 10(8) M-1 at 4 degrees C. This antibody exhibits approximately 40% cross-reactivity with 1-6 dynorphin but very weak cross-reactivities with met5 enkephalin (1.4%), 1-13 dynorphin (1.3%) and beta-endorphin (0.0045%). The detailed study, by competitive assay, of the interaction between this antibody and various enkephalin derivatives shows that the carboxy-terminal part of the molecule and, particularly, the leu side chain constitutes the immunodominant group. Nevertheless, the tyrosyl residue also contribute considerably to the binding, probably via a peculiar conformation effect, although we can not exclude the tyrosyl residue acting as a secondary contact residue. This monoclonal antibody has been used in a radioimmunoassay to determine leu5 enkephalin like immunoreactive material present in rat brain and hypothalamus.
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30
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Abstract
NMR evidence of the temperature dependence of NH resonances and magnitudes of alpha-CH-NH couplings is advanced in support of preferred beta-bend conformations for five enkephalin-like pentapeptides as solutes in DMSO-d6. The relevance of these and related conformational studies to the interactions of peptides of the enkephalin class with opioid receptors is questioned.
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31
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Behnam BA, Deber CM. Evidence for a folded conformation of methionine- and leucine-enkephalin in a membrane environment. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)42694-9] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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32
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Bajusz S, Casy AF. Conformation of a diastereoisomeric pair of enkephalin analogues: A 400 MHz1H NMR study. ACTA ACUST UNITED AC 1984. [DOI: 10.1002/mrc.1270220610] [Citation(s) in RCA: 5] [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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33
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Ishida T, Kenmotsu M, Mino Y, Inoue M, Fujiwara T, Tomita K, Kimura T, Sakakibara S. X-ray diffraction studies of enkephalins. Crystal structure of [(4'-bromo) Phe4,Leu5]enkephalin. Biochem J 1984; 218:677-89. [PMID: 6721829 PMCID: PMC1153395 DOI: 10.1042/bj2180677] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In order to investigate the structure-activity relationship of [Leu5]- and [Met5]enkephalins, [(4'-bromo)Phe4, Leu5]-, [(4'-bromo)Phe4, Met5]- and [Met5] enkephalins were synthesized and crystallized. The crystal structure of [(4'-bromo) Phe4, Leu5]- enkephalin was determined by X-ray diffraction method using the heavy atom method and refined to R = 0.092 by the least-squares method. The molecule in this crystal took essentially the same type I' beta-turn conformation found in [Leu5]enkephalin [Smith & Griffin (1978) Science 199, 1214-1216). On the other hand, the preliminary three-dimensional Patterson analyses showed that the most probable conformations of [(4'-bromo)Phe4,Met5]- and [Met5]enkephalins are both the dimeric extended forms. Based on these insights, the biologically active conformation of enkephalin was discussed in relation to the mu- and delta-receptors.
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34
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Correlation of 15N and 13C relaxation data as a mobility probe for linear peptides. A theoretical and experimental study using enkephalins and related models. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/0022-2364(83)90026-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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35
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Krstenansky JL, Baranowski RL, Currie BL. A new approach to conformationally restricted peptide analogs: rigid beta-bends. 1. Enkephalin as an example. Biochem Biophys Res Commun 1982; 109:1368-74. [PMID: 7168769 DOI: 10.1016/0006-291x(82)91928-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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36
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Mazarguil H, Haran R, Laussac JP. The binding of aluminium to [Leu5]-enkephalin. An investigation using 1H, 13C and 27Al NMR spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 717:465-72. [PMID: 7126641 DOI: 10.1016/0304-4165(82)90289-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The binding of aluminium ion to [Leu5]-enkephalin has been investigated by 1H, 13C and 27Al NMR spectroscopy in dimethyl sulphoxide solution at different peptide/metal ratio. Analysis of the spectra suggests that Al3+ binds at two metal-binding sites. The binding of Al3+ at the first site involves the Tyr1CO, and Leu5COO- groups to give a 2:1 species in a tetracoordinated structure; whereas the binding of Al3+ at the second site utilizes the NH2 terminal groups of the tyrosine moiety in a 2:2 species. 27Al chemical shift values strongly suggest that the second type of aluminium atom displays an octahedral environment. On this basis, we discuss our data in terms of the coordination of aluminium with [Leu5]-enkephalin.
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37
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38
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Demonte JP, Guillard R, Englert A. Theoretical conformational analysis of enkephalin analogues related to fluorescence and n.m.r. measurements in aqueous solution. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1981; 18:478-86. [PMID: 7341529 DOI: 10.1111/j.1399-3011.1981.tb03009.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The properties related to non-radiative energy transfer of a number of enkephalin analogues with tryptophan substituted for phenylalanine in position 4 and n.m.r. 3JNH-C alpha H coupling constants of corresponding [Phe4]-enkephalin analogues are being derived from semi-empirical conformational energy. The molecules considered contain a glycyl, a D-alanyl or an L-alanyl as second residue; two of the compounds are N-methylated at position 4 or 5. The [Trp4]-enkephalin analogues and the corresponding [Phe4]-enkephalin analogues display nearly parallel affinities in the opiate receptor binding assay (Schiller et al. (1). The comparison of computed and experimental properties shows that an ensemble of conformers is a satisfactory representation of the state of these molecules in water.
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39
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Manavalan P, Momany FA. Conformational energy calculations on enkephalins and enkephalin analogs. Classification of conformations to different configurational types. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1981; 18:256-75. [PMID: 7341519 DOI: 10.1111/j.1399-3011.1981.tb02980.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Conformational energy calculations were carried out on the peptide enkaphalins (ENK) and selected analogs to find those conformers of low energy. The analogs studied include [D-Ala2]Enk-NH2, [D-Ala2]Enk, [D-Met2, Pro5]Enk-NH2, [D-Ala2, D-Phe5]Enk, [D-Ala2, D-Leu5]Enk, [D-Ala2, (N-Me)Phe4, Met5] Enk-NH2 and [D-Ala2, (N-Me)Met5]Enk-NH2. When the low-energy conformers for all the analogs are compared, different allowed backbone conformations are found which orient the functional side-chains such that three classifications of structures appear. Each classification shows a unique configuration of side-chain positions in space even though different backbone conformations are found within each classification.
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40
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Marion D, Garbay-Jaureguiberry C, Roques BP. 15N spin-lattice relaxation study of linear peptides: preliminary results on Leu-enkephalin and Tyr-Gly-Gly-Phe. Biochem Biophys Res Commun 1981; 101:711-8. [PMID: 7306111 DOI: 10.1016/0006-291x(81)91809-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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41
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Gidley MJ, Hall LD, Sanders JK, Summers MC. Acetaldehyde--enkephalins: structure proof and some conformational deductions from one- and two-dimensional proton nuclear magnetic resonance spectra. Biochemistry 1981; 20:3880-3. [PMID: 6268150 DOI: 10.1021/bi00516a033] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The structure of the adduct formed by reaction of acetaldehyde and Met5-enkephalin has been determined by analysis of 400-MHz proton spectra: two-dimensional J spectroscopy was used to resolve and measure virtually all the overlapping resonances, and decoupling difference spectroscopy was used to assign the resonances. Suitable manipulation of the two-dimensional data allowed analysis of alpha-CH resonances which were completely buried under a water signal and of amide NH resonances which overlapped in both dimensions. The adduct was shown to be a mixture of two diastereoisomers, each containing a 2-methylimidazolidin-4-one ring formed by condensation of an acetaldehyde molecule with the N-terminal amino group and Gly2 amide nitrogen. Analysis of the NMR data suggests that the folded conformation characteristic of native enkephalins in dimethyl-d6 sulfoxide is not important in these derivatives.
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42
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Roques BP, Garbay-Jaureguiberry C, Bajusz S, Maigret B. Studies of the conformational behaviour and preferential interactions with opiate receptors of the cis and trans forms of [Dmet2,pro5]enkephalin and [Dmet2,pro5]enkephalinamide by 1H and 13C NMR, theoretical calculations and 13C relaxation measurements. EUROPEAN JOURNAL OF BIOCHEMISTRY 1980; 113:105-19. [PMID: 6257512 DOI: 10.1111/j.1432-1033.1980.tb06145.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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43
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Manavalan P, Momany FA. Conformational energy studies on N-methylated analogs of thyrotropin releasing hormone, enkephalin, and luteinizing hormone-releasing hormone. Biopolymers 1980; 19:1943-73. [PMID: 6776998 DOI: 10.1002/bip.1980.360191103] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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44
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Gacel G, Fournie-Zaluski MC, Roques BP. D-Tyr--Ser-Gly--Phe--Leu--Thr, a highly preferential ligand for delta-opiate receptors. FEBS Lett 1980; 118:245-7. [PMID: 6252054 DOI: 10.1016/0014-5793(80)80229-8] [Citation(s) in RCA: 156] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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45
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Han SL, Stimson ER, Maxfield FR, Leach SJ, Scheraga HA. Study of the state of ionization of [Leu5]-enkephalin in the crystal and in solution. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1980; 16:183-90. [PMID: 7461900 DOI: 10.1111/j.1399-3011.1980.tb02951.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The state of ionization of [Leu5]-enkephalin in the crystal and in solution was studied with the aid of Raman, i.r., and n.m.r. techniques. The results indicate that, in the crystal, enkephalin adopts the dipolar ion form. In water near neutral pH, enkephalin also exists in the dipolar ion form whereas in DMSO-d6 it is a mixture of the dipolar ion and uncharged species. The pK's of alpha-amino and alpha-carboxyl groups are probably closer to each other in DMSO than in H2O.
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46
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Higuchi N, Kyogoku Y, Yajima H. NITROGEN-15 NUCLEAR MAGNETIC RESONANCE OF [MET5]-ENKEPHALIN: SIGNAL ASSIGNMENTS AND THE EFFECT OF pH TO THE CHEMICAL SHIFTS. CHEM LETT 1980. [DOI: 10.1246/cl.1980.171] [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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47
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Beddell CR, Lowe LA, Wilkinson S. Endogenous opioid peptides--the enkephalins and endorphins. PROGRESS IN MEDICINAL CHEMISTRY 1980; 17:1-39. [PMID: 6273969 DOI: 10.1016/s0079-6468(08)70156-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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48
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Premilat S, Maigret B. Conformations of angiotensin II and enkephalin related to N.M.R. Biochem Biophys Res Commun 1979; 91:534-9. [PMID: 42398 DOI: 10.1016/0006-291x(79)91555-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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49
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Higashijima T, Kobayashi J, Nagai U, Miyazawa T. Nuclear-magnetic-resonance study on Met-enkephalin and Met-enkephalinamide. Molecular association and conformation. EUROPEAN JOURNAL OF BIOCHEMISTRY 1979; 97:43-57. [PMID: 38962 DOI: 10.1111/j.1432-1033.1979.tb13084.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The 270-MHz 1H and 68-MHz 13C nuclear magnetic resonance spectra of Met-enkephalin (Tyr-Gly-Gly-Phe-Met) and Met-enkephalinamide are analyzed in a variety of solvents. For the dipolar form of Met-enkephalin in (C2H3)2SO solution, significant concentration dependences are found of C-alpha proton chemical shifts, indicating an aromatic ring-current effect in molecular aggregates. An anomalous temperature dependence is observed of the amide proton chemical shift of the Met-5 residue. Furthermore, the chemical shifts of C-alpha protons of the dipolar form are found to depend appreciably on temperature. From the analyses of the temperature dependences together with concentration dependences of C-alpha proton resonances, the dipolar form of Met-enkephalin is found to be in an equilibrium of folded and extended conformations at low concentration in (C2H3)2SO solution. Solvent-composition dependences of the amide and C-alpha proton resonances and carbonyl and alpha-carbon resonances of the dipolar form in 2H2O/(C2H3)2SO solution are consistent with the conformation equilibrium and the association equilibrium. The folded conformation of the dipolar form in (C2H3)2SO solution is stabilized by the intramolecular attraction between the positively charged N-terminal group and negatively charged C-terminal group. The presence of the folded conformation is confirmed by the measurements of Gd(III)-induced relaxation enhancements of C-alpha protons. Nuclear Overhauser effects on the dipolar form are not consistent with the predominant formation of the beta-turn structure with the intramolecular hydrogen bond (Gly-2) C=O . H-N(Met-5). For the dipolar form of Met-enkephalin in 2H2O solution and for the cationic form of Met-enkephalinamide in (C2H3)2SO solution and in 2H2O solution there is no evidence for the formation of folded conformations.
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50
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Gacel G, Fournié-Zaluski MC, Fellion E, Roques BP, Senault B, Lecomte JM, Malfroy B, Swerts JP, Schwartz JC. Conformation and biological activities of hexapeptides related to enkephalins: respective roles of the ammonium and hydroxyl groups of tyrosine. Life Sci 1979; 24:725-31. [PMID: 440018 DOI: 10.1016/0024-3205(79)90354-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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