13C-nuclear magnetic resonance study of [85% 13C-enriched proline]thyrotropin releasing factor: 13C-13C vicinal coupling constants and conformation of the proline residue.

Haar, Wolfgang; Fermandjian, Serge; Vičar, Jaroslav; Bláha, K.; Fromageot, P.

doi:10.1073/pnas.72.12.4948

Cited by 34 publications

(13 citation statements)

References 41 publications

(32 reference statements)

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“…In proline, the 1 J CαC coupling senses the cis/trans isomeric state of the preceding Xaa-Pro peptide bond, with 1 J CαC decreased by 1.4 Hz in the cis state. [43] In DFPase, the peptide link Ala140-Pro141 is cis configured, and so are Asp90-Pro91 and Pro106-Pro107 in Xylanase, and Tyr38-Pro39 and Ser54-Pro55 in RNase T1. [102] Not all proline 1 J coupling constants were available in our dataset, lacking especially some values of 1 J CαN (Table S3).…”

Section: Jmentioning

confidence: 99%

“…Depending markedly on pH in terminal polypeptide residues and free amino acids, [22,23] the 1 J CαC coupling constant is largely pH independent in intrachain residues, averaging 52.8 ± 1.8 Hz. [42,43] The 109 values of 1 in flavodoxin average 52.4 ± 1.9 Hz, essentially uncorrelated with secondary structure or hydrogen-bonding patterns. [44] The 30 values of 1 J CαC reported for troponin C average 53.0 ± 0.7 Hz.…”

Section: Introductionmentioning

confidence: 99%

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Variation in protein C^α‐related one‐bond J couplings

Schmidt¹,

Howard²,

Maestre-Martínez³

et al. 2008

Magnetic Reson in Chemistry

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Four types of polypeptide (1)J(C alpha X) couplings are examined, involving the main-chain carbon C(alpha) and either of four possible substituents. A total 3105 values of (1)J(C alpha H alpha), (1)J(C alpha C beta), (1)J(C alpha C'), and (1)J(C alpha N') were collected from six proteins, averaging 143.4 +/- 3.3, 34.9 +/- 2.5, 52.6 +/- 0.9, and 10.7 +/- 1.2 Hz, respectively. Analysis of variances (ANOVA) reveals a variety of factors impacting on (1)J and ranks their relative statistical significance and importance to biomolecular NMR structure refinement. Accordingly, the spread in the (1)J values is attributed, in equal proportions, to amino-acid specific substituent patterns and to polypeptide-chain geometry, specifically torsions phi, psi, and chi(1) circumjacent to C(alpha). The (1)J coupling constants correlate with protein secondary structure. For alpha-helical phi, psi combinations, (1)J(C alpha H alpha) is elevated by more than one standard deviation (147.8 Hz), while both (1)J(C alpha N') and (1)J(C alpha C beta) fall short of their grand means (9.5 and 33.7 Hz). Rare positive phi torsion angles in proteins exhibit concomitant small (1)J(C alpha H alpha) and (1)J(C alpha N') (138.4 and 9.6 Hz) and large (1)J(C alpha C beta) (39.9 Hz) values. The (1)J(C alpha N') coupling varies monotonously over the phi torsion range typical of beta-sheet secondary structure and is largest (13.3 Hz) for phi around -160 degrees. All four coupling types depend on psi and thus help determine a torsion that is notoriously difficult to assess by traditional approaches using (3)J. Influences on (1)J stemming from protein secondary structure and other factors, such as amino-acid composition, are largely independent.

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Section: Jmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Variation in protein C^α‐related one‐bond J couplings

Schmidt¹,

Howard²,

Maestre-Martínez³

et al. 2008

Magnetic Reson in Chemistry

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“…Interestingly, these values correlate with the mean of the chemical shifts of the coupled atoms C', C", and C", C@, which are dif- At the same time, 4.1 Hz is found for 3 J~' 1 ca and no 3Jc,.c1 and 3Jc,.c~ are observed in the trans conformer, similar to other proline peptides where the pyrrolidine ring exhibits mainly the type A puckering. 17,20,23 On the other hand, it has been shown that when the difference between ' J H~~H P and 3 J~c y~~ reaches its maximum ( " J H~H P -0), the H(Y resonance is most strongly shifted downfield (4.7 ppm).57 Thus the proline Ha chemical shifts and the " J H~H~? and : ' J H~+~ couplings are both influenced by steric factors affecting the geometry of the proline residue.…”

Section: Proline Ring Conformationmentioning

confidence: 94%

NMR evidence for a type I β‐turn in (Pro²)‐tetrapeptides and interdependence of cis:Trans isomerism, ring flexibility, and backbone conformation

et al. 1980

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SynopsisTetrapeptides with proline in position 2, asparagine or leucine in position 3, and glycine in positions 1 and 4, with end groups free or blocked on the N-terminal side, were studied in their various ionic states in 2H20 and in MeZSO-ds by 'H-and '%nmr.In order to clarify or refine some details, successive substitutions of the residues in these peptides with amino acids enriched to 85% in I3C, or to 85% 13C plus 97% *H were carried out. The 'H and 13C chemical shifts as well as the 'H-'H, 13C-W, and 13C-lH coupling constants and the signal intensities show strong similarity of behavior between the tetrapeptides of asparagine and leucine. The main conformational characteristics are (1) the almost total stabilization of the trans conformer in the type I P-turn structure when the peptide is in the zwitterion state dissolved in MeZSO. This is deduced from the and the 3 J~; .~3 9 .coupling constants, which both furnish a dihedral angle of = -go", and from the positive value of the temperature coefficient of the glycine-4 amide protons, which suggests a type 4 -1 hydrogen bond;(2) the evolution of cis and trans isomer fractions which change with the ionic state of the peptides in Me2.90, whereas they remain constant in aqueous solution; and (3) the conformation of the pyrrolidine ring as it follows the variations in cis:trans isomer populations together with the side-chain rotamer fractions of the residue in position 3. In the @-turn conformation the isomer cis is less abundant and the pyrrolidine ring is more flexible; this explains the perfect accommodation of the proline residue in position 2 of a bend. The interdependence of these phenomena where interactive forces play a predominant role underlines the importance of cooperative effects in the molecule. The results also suggest that the cis isomer of proline can adapt itself just as well as the trans isomer to position 2 of a type I @-turn.

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“…Photolyses were carried out using a 450 W Hsnovia medium pressure Hg lamp. Thin layer chromatography was performed on Whatman precoated silica gel plates using the following solvent systems: (I) hexanesether (2 : 1); (11) Polypropylene 74p mesh packets (50 x 50 mm) were prepared as previously HF cleavage of the peptide from the resin was effected using a HF reactor, type I apparatus (Protein Research Foundation, Osaka, Japan). Optical rotations were measured using a Perkin-Elmer Model 141 polarimeter.…”

Section: Met Hodsmentioning

confidence: 99%

Synthesis and conformational studies by ¹H‐ and ¹³C‐nmr spectroscopy of a novel, sterically constrained analogue of thyrotropin‐releasing hormone

1990

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A novel thyrotropin-releasing hormone (TRH) analogue, [2,4-MePro3]-TRH (2,4-MePro: 2-carboxy-2,4-methanopyrrolidine), has been synthesized using a rapid solid phase peptide synthesis method, and its conformational properties investigated by one- and two-dimensional (2D) nmr spectroscopy and by proton Overhauser measurements. Following a published approach, calibrated interproton Overhauser effects were used together with distance geometry analysis to deduce that the single conformation of the His-2,4-MePro tertiary amide bond is trans in aqueous solution. This conclusion was corroborated by 2D dipolar-correlated (NOESY) spectroscopy. A preferentially extended conformation is indicated by the nmr data, similar to that of TRH. The phi, psi conformational space of 2,4-MePro is, however, significantly different from that of trans proline and the structural consequences of these differences at the C-terminus are discussed. The distribution of histidine side-chain conformations in the TRH analogue was deduced from coupling constants and from the short-range interaction between the imidazole ring and one of the prochiral faces of the 2,4-MePro side chain.

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13C-nuclear magnetic resonance study of [85% 13C-enriched proline]thyrotropin releasing factor: 13C-13C vicinal coupling constants and conformation of the proline residue.

Abstract: To understand fully interactions between peptides and cellular receptors, peptide side chain conformation must be defined. In many cases the complexity of proton nuclear magnetic resonance (NMR)

Cited by 34 publications

References 41 publications

Variation in protein C^α‐related one‐bond J couplings

Variation in protein C^α‐related one‐bond J couplings

NMR evidence for a type I β‐turn in (Pro²)‐tetrapeptides and interdependence of cis:Trans isomerism, ring flexibility, and backbone conformation

Synthesis and conformational studies by ¹H‐ and ¹³C‐nmr spectroscopy of a novel, sterically constrained analogue of thyrotropin‐releasing hormone

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13C-nuclear magnetic resonance study of [85% 13C-enriched proline]thyrotropin releasing factor: 13C-13C vicinal coupling constants and conformation of the proline residue.

Abstract: To understand fully interactions between peptides and cellular receptors, peptide side chain conformation must be defined. In many cases the complexity of proton nuclear magnetic resonance (NMR)

Cited by 34 publications

References 41 publications

Variation in protein Cα‐related one‐bond J couplings

Variation in protein Cα‐related one‐bond J couplings

NMR evidence for a type I β‐turn in (Pro2)‐tetrapeptides and interdependence of cis:Trans isomerism, ring flexibility, and backbone conformation

Synthesis and conformational studies by 1H‐ and 13C‐nmr spectroscopy of a novel, sterically constrained analogue of thyrotropin‐releasing hormone

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Variation in protein C^α‐related one‐bond J couplings

Variation in protein C^α‐related one‐bond J couplings

NMR evidence for a type I β‐turn in (Pro²)‐tetrapeptides and interdependence of cis:Trans isomerism, ring flexibility, and backbone conformation

Synthesis and conformational studies by ¹H‐ and ¹³C‐nmr spectroscopy of a novel, sterically constrained analogue of thyrotropin‐releasing hormone