Deltorphin I, a delta-selective opioid peptide, has been studied in a DMSO(d6)/H2O cryoprotective mixture by two-dimensional (2D) NMR spectroscopy in the temperature range 260 K to 305 K. The high viscosity of the solvent at low temperature mimics a distinctive physico-chemical feature of cytoplasm and allows the measurement of a NOESY spectrum rich in intra- and inter-residue effects. Backbone NOEs at 265 K can be calculated with good accuracy in terms of only two limiting conformers: one folded, with a mole fraction of 0.30, and another extended with a mole fraction of 0.70. This calculation is still a rough approximation of the complex conformational equilibria existing in solution but, to the best of our knowledge, is the first one for a flexible peptide, and represents an encouraging starting point for a quantitative evaluation of NMR data of small, flexible peptides in solution. The folded conformer consistent with observed NOEs has a shape surprisingly similar to those of unrelated, rigid, delta-selective opiates.
Solution Structure of Deltorphin-i At 265-k - A Quantitative Nmr-study / P., A., A., M., T., T., S., S., R., T., Picone, D., G., S., P. A., T.. - In: PEPTIDE RESEARCH. - ISSN 1040-5704. - STAMPA. - 5:(1992), pp. 48-55.
Solution Structure of Deltorphin-i At 265-k - A Quantitative Nmr-study
PICONE, DELIA;
1992
Abstract
Deltorphin I, a delta-selective opioid peptide, has been studied in a DMSO(d6)/H2O cryoprotective mixture by two-dimensional (2D) NMR spectroscopy in the temperature range 260 K to 305 K. The high viscosity of the solvent at low temperature mimics a distinctive physico-chemical feature of cytoplasm and allows the measurement of a NOESY spectrum rich in intra- and inter-residue effects. Backbone NOEs at 265 K can be calculated with good accuracy in terms of only two limiting conformers: one folded, with a mole fraction of 0.30, and another extended with a mole fraction of 0.70. This calculation is still a rough approximation of the complex conformational equilibria existing in solution but, to the best of our knowledge, is the first one for a flexible peptide, and represents an encouraging starting point for a quantitative evaluation of NMR data of small, flexible peptides in solution. The folded conformer consistent with observed NOEs has a shape surprisingly similar to those of unrelated, rigid, delta-selective opiates.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
