500 MHz NMR characterization of synthetic bombesin and related peptides in DMSO‐d<sub>6</sub> by two‐dimensional techniques

Bello, Carlo Di; Gozzini, Luigia; Tonellato, Mauro; Corradini, Maria G.; D’Auria, Gabriella; Paolillo, Livio; Trivellone, E.

doi:10.1016/0014-5793(88)80177-7

Cited by 17 publications

(65 citation statements)

References 6 publications

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“…In fact, the NOE effects in the 6-13 fragment of BN demonstrate that this section is not as mobile as the Nterminus. 32 This finding may reflect a tendency to a possible structuring of this part of the peptide chain, indicating that the hepta-to nonapeptide segment of the C-terminus of bombesin contains the pharmacologic message for triggering the biological responses (Trp 8 and His 12 are essential for biologic activity) 33 and is believed to be responsible for receptor recognition. 26,34 The biological importance of the above-described neurotransmitter has motivated us to perform a number of spectroscopic studies on it.…”

Section: Introductionmentioning

confidence: 96%

Investigation of molecular structure of bombesin and its modified analogues nonadsorbed and adsorbed on electrochemically roughened silver surface

Podstawka

2007

Biopolymers

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This work describes the molecular structure of bombesin (BN) and its analogs on the basis of the absorption infrared and Raman results described below. In these analogues is replaced one ([D-Phe12]BN, [Tyr4]BN, and [Lys3]BN) or two ([Tyr4,D-Phe12]BN, [D-Phe12,Leu14]BN, and [Leu13-(R)-Leu14]BN) amino acid residues within the peptide chain with a synthetic amino acid, creating antagonists to bombesin, which are useful in the treatment of cancer. It is also used surface enhanced Raman scattering (SERS) to study the differences and changes in the vibrational spectra of BN and its analogs, which were attached to an electrochemically roughened silver surface as these peptides interacted with target proteins. This work explores the use of SERS for molecules anchored to a macroscopic silver surface to interrogate the interaction of these peptides with protein receptors. The results presented here show that all peptides coordinate to the macroscopic silver surface through an indole ring and the methylene group of Trp8, the C==O fragment, and an amide bond; however, the orientation of these fragments on the electrochemically roughened silver surface and the strength of the interactions with this surface is slightly different for each peptide. For example, the interaction of --CH2-- of [D-Phe12]BN, [Tyr4,D-Phe12]BN, [D-Phe12,Leu14]BN, [Leu13-(R)-Leu14]BN, and [Lys3]BN with the silver surface perturbed the vertical orientation of the Trp8 indole ring on this surface. Hence, the indole ring adopted a close to perpendicular orientation on the silver surface for BN and [Tyr4]BN, only.

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Section: Introductionmentioning

confidence: 96%

Investigation of molecular structure of bombesin and its modified analogues nonadsorbed and adsorbed on electrochemically roughened silver surface

Podstawka

2007

Biopolymers

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“…In this regard, several series of G-protein-coupled receptor antagonists have been developed and tested. These have illuminated some important structural components that might contribute to the unique ability of these peptides to interact with rGRP-R (bombesin/GRP-preferring subtype receptor) with high affinity. − These peptides include BN analogues and fragments resulting from side chain modification strategies (amino acid deletions or the retro-inverso modification); peptides with modified peptide bonds; peptides with a modified or deleted C-terminal region; and bombesin-related peptides. It has been demonstrated, for example, that the C-terminal nanopeptide (BN 6−14 ) is the minimal fragment required for full BN affinity. , It has also been determined that deletion or substitution of the L -tryptophan residue in position 8 of the BN amino acid sequence (Trp 8 ) produces an inactive analogue.…”

Section: Introductionmentioning

confidence: 99%

Potential-Dependent Studies on the Interaction between Phenylalanine-Substituted Bombesin Fragments and Roughened Ag, Au, and Cu Electrode Surfaces

2009

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In this work, we report systematic surface-enhanced Raman spectroscopy (SERS) and generalized two-dimensional correlation analysis (G2DCA) studies of the structures of five specifically modified phenylalanine-substituted C-terminal bombesin 6-14 fragments (BN(6-14)). The fragments studied have all been tested as chemotherapeutic agents in cancer therapy, and they form amino acid sequences in bombesin: cyclo[d-Phe(6),His(7),Leu(14)]BN(6-14), [D-Phe(6),Leu-NHEt(13),des-Met(14)]BN(6-14), [D-Phe(6),Leu(13)-((R))-p-Cl-Phe(14)]BN(6-14), [D-Phe(6),beta-Ala(11),Phe(13),Nle(14)]BN(6-14), and [D-Tyr(6),beta-Ala(11),Phe(13),Nle(14)]BN(6-14). We adsorbed these fragments onto roughened Ag, Au, and Cu electrode surfaces, using a potential range from -1.200 to 0.400 V, at physiological pH. We compared the adsorption mechanism of each fragment on these substrates, as well any changes observed with varying electrode potential, to determine the relationship between adsorption strength and geometry of each of the peptides wherever it was possible. For example, we showed that none of these fragments directly interact with the Ag, Au, and Cu surfaces via residues of Phe (phenylalanine) and Trp(8) (L-tryptophane at position 8 of the BN amino acid sequence) or by an amide bond, due to a very small shift in wavenumber of their characteristic vibrations. Specific interactions were recognized from the broadening, wavenumber shift, and increase in intensity of the W18 Trp(8) mode near 759 cm(-1) and decrease in nu(12) vibration frequency of the Phe residue. In general, more intense SERS bands were observed due to the Phe ring, compared with the Trp(8) ring, which suggested a preferential adsorption of phenylalanine over tryptophane. For [D-Tyr(6),beta-Ala(11),Phe(13),Nle(14)]BN(6-14), the data also suggest some interaction of a D-Tyr(6) residue (D-tyrosine at position 6). Finally, only slight rearrangements of these moieties on the substrates are observed with changes in electrode potential.

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“…MDS where the starting structure is in -hairpin conformation, indicates that unfolding does not occur as in the pG peptide. NMR studies indicate that several short peptides are unstructured in DMSO (13)(14)(15)(16).…”

Section: Resultsmentioning

confidence: 99%

“…This solvent is generally used to dissolve aggregating peptides such as amyloidogenic peptides to break up any secondary structures [12]. Infact, several peptides that are not composed of hydrophobic amino acids do not adopt folded structures in DMSO [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics simulations of hydrophobic peptides that form β-hairpin structures in solution

Moharana

Nagaraj

2021

Preprint

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Peptides designed with residues that have high propensity to occur in β-turns, form β-hairpin structures in apolar solvents as well in polar organic solvents such as dimethyl sulfoxide (DMSO), methanol and varying percentages of DMSO in chloroform (CHCl3). Presumably due to limited solubility, their conformations have not been investigated by experimental methods in water. We have examined the conformations of such designed peptides that fold into well-defined β-hairpin structures facilitated by β-turns, in the crystalline state and in solution, by Molecular Dynamics Simulations (MDS). The peptides fold into β-hairpin structures in water, starting from extended conformation. In DMSO, folding into β-hairpin structures was not observed, starting from extended conformation. However, when the starting structure is in β-hairpin conformation, unfolding is not observed during MDS in DMSO. Water clearly favours folding of short, hydrophobic peptides into β-turn and β-hairpin conformations from extended structures. DMSO does not have a denaturing effect on short, hydrophobic peptides.

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500 MHz NMR characterization of synthetic bombesin and related peptides in DMSO‐d₆ by two‐dimensional techniques

Cited by 17 publications

References 6 publications

Investigation of molecular structure of bombesin and its modified analogues nonadsorbed and adsorbed on electrochemically roughened silver surface

Investigation of molecular structure of bombesin and its modified analogues nonadsorbed and adsorbed on electrochemically roughened silver surface

Potential-Dependent Studies on the Interaction between Phenylalanine-Substituted Bombesin Fragments and Roughened Ag, Au, and Cu Electrode Surfaces

Molecular dynamics simulations of hydrophobic peptides that form β-hairpin structures in solution

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500 MHz NMR characterization of synthetic bombesin and related peptides in DMSO‐d6 by two‐dimensional techniques

Cited by 17 publications

References 6 publications

Investigation of molecular structure of bombesin and its modified analogues nonadsorbed and adsorbed on electrochemically roughened silver surface

Investigation of molecular structure of bombesin and its modified analogues nonadsorbed and adsorbed on electrochemically roughened silver surface

Potential-Dependent Studies on the Interaction between Phenylalanine-Substituted Bombesin Fragments and Roughened Ag, Au, and Cu Electrode Surfaces

Molecular dynamics simulations of hydrophobic peptides that form β-hairpin structures in solution

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500 MHz NMR characterization of synthetic bombesin and related peptides in DMSO‐d₆ by two‐dimensional techniques