Stabilization of the peptide conformation on the micellar surface

Abstract

The conformational mobility of peptide molecules plays a significant role in peptide-receptor interactions and quantitative structure-activity relationships. As a receptor mimetic system, bis(2-ethylhexyl) sodium succinate (AOT) reversed micelles containing an aqueous solution of one of the melanotrophine inhibiting factor analogues prolyltyrosyl-glycinamide hydrochloride in the inner cavity have been used. Two-dimensional nuclear magnetic resonance spectroscopy (NOESY) and 13C spin-lattice relaxation time measurements have been used to establish that the peptide molecule assumes the biologically active beta II turn conformation when it is adsorbed at the surfactant-water border. This conformation is stabilized by intramolecular H-bonding between the proline carbonyl oxygen atom and amide protons. Moreover, it has been shown that the phenyl ring of tyrosine was inserted into the AOT intermolecular cavity, which is located between the polar AOT groups and the branches of iso-octane fragments. By and large, the phenyl ring acts as a hydrophobic anchor. Reversed micelles can be regarded as providing a realistic model of the receptor.

Conformational preferences of Leu‐enkephalin in reverse micelles as membrane‐mimicking environment

“…This is different from vesicles where about 2000-3000 phospholipid monomers are on enkephalins by x-ray analysis of crystals grown under different conditions, 7 by nmr analysis in solu-needed to form a single liposome 24 ; in reverse micelles the surfactant aggregation number is°100. 12,13,25,26 Met-enkephalin has been thus exclude aggregational phenomena even at mmolar peptide concentrations as required for nmr analyzed by nmr spectroscopy in AOT/reverse micelles 12,13 using temperature dependence measure-experiments. 12,13,25,26 Met-enkephalin has been thus exclude aggregational phenomena even at mmolar peptide concentrations as required for nmr analyzed by nmr spectroscopy in AOT/reverse micelles 12,13 using temperature dependence measure-experiments.…”

“…the tripeptide H-Pro-Tyr-Gly-NH 2 in AOT reverse micelles,26 where the NOEs from a The correction values for the pseudoatoms were taken from the Tyr aromatic and b-methylene protons as literature 42. …”

Effects of protein solubilization on the structure of the surfactant shell of reverse micelles

“…However, it should be kept in mind that a catalytic system "enzyme-reverse micelle" is ah indivisible one and as the micelle affects the protein properties, so there has to be an opposite action. Many fundamental questions for the complete understanding of the enzyme solubilization and functioning in the water-in-oil microemulsions remain unanswered [10][11][12][13][14]. For example, there are not enough data on the properties of the interfacial surfactant layer under the influence of the encapsulated protein.…”