Peptide conformation. 18. Analysis of the conformational equilibrium of cyclo[Pro-NBGly2] by means of two-dimensional NMR spectroscopy

Application of two-dimensional NMR to kinetics of chemical exchange

“…Interconversion between two conformational isomers of the cyclic tripeptide cydo[Pro-NBGly2] (Scheme 16), where NBGly = N-(o-nitrobenzyl)glycyl, was detected by *H 2D SECSY. 90 The ID spectrum in CDC13 solution is quite complex with many overlapping signals due to boat and crown conformers in ratio 20:80. The ring-inversion process that interconverts the two conformers was observed in the 2D exchange spectrum at 58 °C.…”

Synthesis, Structure, and Properties of MeSer1-Tentoxin, a New Cyclic Tetrapeptide Which Interacts Specifically with Chloroplast F1H+-ATPase Differentiation of Inhibitory and Stimulating Effects

“…A crucial step in this kind of study is the determination of the structure in solution of the effector and its analogues. Since they have a limited number of conformations, small cyclic peptides are especially suitable for such investigations (Blout, 1981;Kessler, 1982;Kessler et al, 1982). In addition, such an approach can give some clues concerning the molecular pattern relevant to a given biological activity, on the basis of experimental structural differences and similarities.…”

Structural and conformational analysis by 1H NMR and 13C NMR of a new angiotensin I converting enzyme inhibitor, the tert‐butylamine salt of (2S)‐2‐[(1S)‐1‐carbethoxybutylamino]‐1‐oxopropyl‐(2S, 3aS, 7aS) perhydroindole‐2‐carboxylic acid (perindopril)

“…The relative intensities were different in CDCl, (80: 20) and in CD,OD (60 : 40), and equal in CD,SOCD, . As a result, the 'H NMR spectra of 1 are far more complex than those of 2, even when recorded at high frequency (500 MHz).…”