Proton NMR of the protected tetrapeptides TFA-Gly-Gly-l-X-l-Ala-OCH3, where X stands for One of the 20 common amino acids

Bundi, Arno; Grathwohl, Christoph; Hochmann, Jiri; Keller, Regula M.; Wagner, Gerhard; Wüthrich, Kurt

doi:10.1016/0022-2364(75)90237-1

Cited by 67 publications

(44 citation statements)

References 12 publications

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“…Table 2 shows that the indole ring of Trp-23 is preferentially oriented towards the amino terminus of the peptide. A similar preferential spatial arrangement of aromatic side-chains was found to be typical even for flexible linear oligopeptides, such as those used to obtain the 'random coil' values listed in Table 2 [8,16,17]. The vicinal spin-spin coupling constant 3J,/1 of Val-21 in the partial sequences 20-23 or 20-24 corresponds to a population of the trans rotation state of 0.45 (Table 1).…”

Section: Resultsmentioning

confidence: 59%

Characterisation of a Local Structure in the Synthetic Parathyroid Hormone Fragment 1-34 by 1H Nuclear-Magnetic-Resonance Techniques

Bundi¹,

Andreatta

Wüthrich³

1978

Eur J Biochem

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Previous studies had shown that the molecular conformation of the synthetic human parathyroid hormone fragment 1 -34 in dilute aqueous solution contained a local non-random structure formed by the four consecutive residues -Val-21 -Gln-22 -Trp-23 -Leu-24 -. This paper gives a detailed description of this local spatial structure obtained from high resolution 'H NMR studies at 360 MHz of several peptide analogs of the partial sequence 20-24. The most important spectral parameters were high-field shifts of the a and y protons of Val-21, the spin-spin coupling constants related to the rotamer populations of the side-chains of Val-21 and Trp-23, and pH titration shifts of the amide proton resonances. It was found that the backbone fragment 20-24 is so arranged that the side-chain of Val-21 is located next to the indole ring plane of Trp-23; evidence is presented that this non-random structure is mainly stabilized by hydrophobic interactions between the side-chains of Val-21 and Trp-23. The thermal population of the observed molecular structure at room temperature was estimated from the nuclear magnetic resonance data to be approximately 20%.In a previous paper it was shown that the synthetic human parathyroid hormone fragment 1 -34 exists in aqueous solution predominantly in a flexible extended form, where, however, a local non-random structure was also clearly manifested in the ' H nuclear magnetic resonance (NMR) parameters [l]. This non-random conformation was then found to involve the amino acid residues -Val-21 -Gln-22-Trp-23 -Leu-24 -, and it was demonstrated that the same structure was preserved in the pentapeptide Arg-Val-Gln-Trp-Leu[l]. Our interest in this structure was further enhanced, since the tetrapeptide sequence 21 -24 in the parathyroid hormone corresponds to the tetrapeptide sequence 23 -26 in glucagon [2,3]. The present paper describes a detailed investigation of the spatial arrangement of the tetrapeptide segment 21 -24 in the parathyroid hormone 1 -34.The strategy used for this study was to compare the spatial structures of different synthetic peptide analogs by high-resolution 'H NMR techniques. On the basis of the requirements of compatibility with all the NMR data and with the criteria of closest interAbhreviations. NMR, nuclear magnetic resonance; parathyroid hormone 1 -34, synthetic N-terminal fragment 1 -34 of the human parathyroid hormone. atomic distances, a molecular model for the tripeptide segment -Val-21 -Gln-22 -Trp-23 -in the parathyroid hormone 1 -34 was constructed. With the use of the atomic coordinates obtained from this model, the thermal population of the local spatial structure was estimated in a quantitative analysis of the NMR data. MATERIALS AND METHODS Peptidr SynthesisThe synthesis of parathyroid hormone 1-34 according to the sequence determined by Brewer et al. [4] and of several partial sequences thereof was described previously [ 5 ] . This concerns in particular the partial sequences Met-1

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Section: Resultsmentioning

confidence: 59%

Characterisation of a Local Structure in the Synthetic Parathyroid Hormone Fragment 1-34 by 1H Nuclear-Magnetic-Resonance Techniques

Bundi¹,

Andreatta

Wüthrich³

1978

Eur J Biochem

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“…Fig. 1 illustrates the chemical shift differences of the a protons between the measured values in NPY 13-36 and the reported values in ('H,)Me,SO [27]. Such values have been demonstrated to be indicative of secondary structure in peptides and proteins [28, 291.…”

Section: Resultsmentioning

confidence: 96%

Solution Structure of Neuropeptide Tyrosine 13–36, a Y2 Receptor Agonist, as Determined by NMR

Labelle

St‐Pierre

Savard

et al. 1997

European Journal of Biochemistry

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The three-dimensional structure of neuropeptide tyrosine (NPY) 13 -36, a specific Y2 receptor agonist, has been investigated by two-dimensional 'H-NMR spectroscopy in solution. Analysis of the doublequantum-filtered correlation spectroscopy (DQFCOSY), total correlation spectroscopy (TOCSY) and nuclear Overhauser enhancement spectroscopy (NOESY) spectra provided a complete assignment of the proton signals. The interproton connectivities observed in the NOESY spectra comprised 166 intraresidue and 95 interresidue distance ranges which were used as constraints for molecular modeling by distance geometry, simulated annealing and energy minimization. The optimal structures are characterized by a helical C-terminal fragment Leu30-Tyr36 and a wide loop from Leu17 to Ser22. The structure of NPY 13-36 is analogous to the structure of NPY under the same solvent conditions. Comparison with other reported Y2 agonists suggests that the helical Leu30-Tyr36 fragment is the most critical for activity.Keywords : neuropeptide tyrosine agonist ; three-dimensional structure; NMR; molecular modeling.Neuropeptide tyrosine or NPY is a 36-amino acid peptide belonging to a family of biologically active peptides which includes peptide YY (PYY) and pancreatic polypeptide (PP). NPY is widely distributed in both the central and peripheral nervous systems and produces a variety of effects especially on the feeding behavior, cardiovascular function and anxiety [ l , 21. Its structure is characterized by the presence of five tyrosine and of four proline residues concentrated in a N-terminal polyproline segment.NPY performs its varied biological functions through the interaction with distinct G-protein-coupled receptor subtypes. Responses to Pro34] The three-dimensional structure of NPY has been investigated by two-dimensional 'H-NMR spectroscopy [12-16) and molecular modeling based on the crystal structure of PP [17-191. All investigations agree on the general structure of NPY which is folded in its center forming a hairpin structure with the N-and C-terminal segments in close proximity. The N-terminal polyproline segment (residues 1 -13) is generally disordered and the C-terminal segment (residues 15 -36) is generally helical, [20-221 and 1,1,1,3,3,3-hexa-fluoro-2-('H2)propano1/20 mM aqueous ('HJacetic acid (3 : 7 at pH 2.7) [23]. Recently, NMR data were reported for NPY 13-36 in ('H,)TFE/water (9 : 1) but the three-dimensional structure could not be determined due to resonance overlap [24]. However, the chemical shift values for the NH and a protons are consistent with helical structure.In this study, the structure of the most common Y2 receptor agonist, NPY 13 -36, has been determined by two-dimensional NMR spectroscopy and molecular modeling. Experiments were performed in deuterated dimethylsulfoxide [(2H,)Me,SO], a solvent of medium polarity which should represent the various media in which the peptide can exist and which is not a helix inducer. These conditions allow us to compare the structure of this fragment with our previously repor...

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“…The large discrepancies for these P-substituted amino acids (0.21 and 0.29ppm, respectively) compared to an average downfield of 0.07 ppm in this solvent mixture suggest that perfluoro-tert-butanol and H,O may favor different preferential conformers for these residues. However, the overall C,H similarity in chemical shifts confirms that these protons are only slightly affected by the proton accepting or donating property of solvents such as Me,SO [45], H,O [44] and perfluoro-tert-butanol/CD,OD. In contrast, perfluorotert-butanol dramatically upfield-shifted all the amide protons, in connection with its proton-donating capability [46].…”

Section: Conformations In Meso and Meso/cdc1(4 : 6)mentioning

confidence: 84%

“…2). The presence of an acetyl and a C-terminal amide group instead of a trifluoroacetyl and a C-terminal free acid did not significantly alter the statistical values of dcCoH, even though some residues may present (as in water [44] or M e 8 0 [45] solution) preferential conformations as indicated by AS,,/ATmeasurements for various tetrapeptides (X = N, T, V, W, A, G ; data not shown). Almost all the chemical shifts observed for CaH protons in perfluoro-tert-butanoV CD,OD(9: 1) are very close to those reported for aqueous solution [44] except for threonine and cysteine (oxidized form).…”

Section: Conformations In Meso and Meso/cdc1(4 : 6)mentioning

confidence: 88%

Three‐Dimensional Structure of the Highly Conserved Seventh Transmembrane Domain of G‐Protein‐Coupled Receptors

Berlose

Convert

Brunissen

et al. 1994

European Journal of Biochemistry

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The S/T-XI-X,-N-P-X,-X,-Y highly conserved sequence of the seventh transmembrane (TM VII) segment of G-protein-coupled receptors is not present in the photon receptor bacteriorhodopsin TM VII domain. Despite this noticeable discrepancy in sequence, the X-ray structure of bacteriorhodopsin is generally used as the key structure for modelling all G-protein-coupled receptors. Thus, a kinked truns-Pro helix is usually accepted for the TM VII three-dimensional structure of G-proteincoupled receptors, although Asn-Pro dipeptide mainly induces a type UIII /3-turn conformation in both model peptides and proteins. NMR studies in various solvents and molecular calculations were undertaken in order to gain insight into the conformational behaviour of a 15-residue peptide from the tachykinin NK-1 TM VII domain incorporating this common sequence. The low solubility of this membrane-embedded peptide precludes methanol or micellar systems mimicking membrane environment; thus only dimethylsulfoxide (Me,SO) or chlorofonn/Me,SO mixture could be used. We also found that perfluoro-tert-butanol, which has not been previously used for NMR studies, constitutes an excellent alternative solvent for the analysis of hydrophobic peptides. The postulated kinked truns-Pro helix was only present as a minor conformer in Me,SO and an equilibrium between helical and extended structures existed. From NOE data a type I/III ,&structure, centered around Pro9-Ile10, probably stabilized by an Asx turn, may be postulated. Addition of chloroform in Me,SO increased the percentage of folded structures but no preferential conformation could be proposed. In perfluoro-tert-butanoI/CD,OD (9 : 1) the N-and C-terminal regions presented an a-helical structure, and these two domains were linked by a hinge around Asn-Pro with a y-turn for the preceding residue Tyr7 and either a type I/III p-turn around Pro9-IlelO or cxR orientations for these residues, which are both stabilized by an Asx turn. As determined by energy calculations, these structures were equally as stable as the kinked truns-Pro helix and could constitute key structures for analysing the conformational changes and/or the dynamics of TM VII segment induced by the ligand when interacting with the receptor.The apparent similarity in the hydropathicity profiles of G-protein-coupled receptors [ 1 -41 with that of bacteriorhodopsin [5] has led to the use of this integral membrane protein as a starting point for predicting their three-dimensional structures [6-121, even though bacteriorhodopsin is not coupled to G-proteins. The currently accepted proposal for the topography of G-protein-coupled receptors includes seven transmembrane-spanning domains (TM I-VII) joined together by extracellular and cytoplasmic loops, with the Nterminal side in the extracellular cleft and the C-terminal residues in the cytoplasm. This model, which was first deduced Correspondence to S .

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Proton NMR of the protected tetrapeptides TFA-Gly-Gly-l-X-l-Ala-OCH3, where X stands for One of the 20 common amino acids

Cited by 67 publications

References 12 publications

Characterisation of a Local Structure in the Synthetic Parathyroid Hormone Fragment 1-34 by 1H Nuclear-Magnetic-Resonance Techniques

Characterisation of a Local Structure in the Synthetic Parathyroid Hormone Fragment 1-34 by 1H Nuclear-Magnetic-Resonance Techniques

Solution Structure of Neuropeptide Tyrosine 13–36, a Y2 Receptor Agonist, as Determined by NMR

Three‐Dimensional Structure of the Highly Conserved Seventh Transmembrane Domain of G‐Protein‐Coupled Receptors

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