N-Myristoylethanolamine-cholesterol (1:1) complex: first evidence from differential scanning calorimetry, fast-atom-bombardment mass spectrometry and computational modelling.
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 degrees C besides the chain-melting transition of NMEA at 72.5 degrees 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.
Ramakrishnan
M
M
School of Chemistry, University of Hyderabad, Hyderabad, India.
Kenoth
Roopa
R
Kamlekar
Ravi Kanth
RK
Chandra
M Sharath
MS
Radhakrishnan
T P
TP
Swamy
Musti J
MJ
D002152:Calorimetry, Differential Scanning; D002784:Cholesterol / Q000737:chemistry* / Q000378:metabolism; D019295:Computational Biology; D004983:Ethanolamines / Q000737:chemistry* / Q000378:metabolism; D006860:Hydrogen Bonding; D046911:Macromolecular Substances; D008958:Models, Molecular; D009226:Myristates / Q000737:chemistry* / Q000378:metabolism; D016339:Spectrometry, Mass, Fast Atom Bombardment
D004983:Ethanolamines; D046911:Macromolecular Substances; D009226:Myristates; D002784:Cholesterol