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N ‐Myristoylethanolamine–cholesterol (1:1) complex: first evidence from differential scanning calorimetry, fast‐atom‐bombardment mass spectrometry and computational modelling
Author(s) -
Ramakrishnan M,
Kenoth Roopa,
Kamlekar Ravi Kanth,
Chandra M.Sharath,
Radhakrishnan T.P,
Swamy Musti J
Publication year - 2002
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(02)03553-6
Subject(s) - differential scanning calorimetry , enthalpy , chemistry , mass spectrometry , fast atom bombardment , cholesterol , molecule , mass spectrum , analytical chemistry (journal) , chromatography , thermodynamics , organic chemistry , biochemistry , physics
The interaction of N ‐myristoylethanolamine (NMEA) with cholesterol is investigated by differential scanning calorimetry (DSC), fast‐atom‐bombardment mass spectrometry (FAB‐MS) and computational modelling. Addition of cholesterol to NMEA leads to a new phase transition at 55°C besides the chain‐melting transition of NMEA at 72.5°C. The enthalpy of the new transition increases with cholesterol content up to 50 mol%, but decreases thereafter, vanishing at 80 mol%. The enthalpy of the chain‐melting transition of NMEA decreases with an increase in cholesterol; the transition disappears at 50 mol%. FAB‐MS spectra of mixtures of NMEA and cholesterol provide clear signatures of the formation of {[NMEA+cholesterol] + } {[NMEA+cholesterol+Na] + }. These results are consistent with the formation of a 1:1 complex between NMEA and cholesterol. Molecular modelling studies support this experimental finding and provide a plausible structural model for the complex, which highlights multiple H‐bond interactions between the hydroxy group of cholesterol and the hydroxy and carbonyl groups of NMEA besides appreciable dispersion interaction between the hydrocarbon domains of the two molecules.