Structural studies of biological membranes and related model systems by Raman spectroscopy. Sphingomyelin and 1,2-dilauroyl phosphatidylethanolamine.

Raman spectra are reported at relatively high resolutions (1.5 cm-1) for sphingomyelin and for 1,2-dilauroyl phosphatidylethanolamine above and below their melting temperatures. The spectra of 1,2-dilauroyl phosphatidylethanolamine below Tm show the hydrocarbon chains to be less ordered in the solid phase than the fatty acid of the same chain length, without the significant occurrence of guache isomers. The spectra of sphingomyelin show significant formation of gauche isomers below Tm, indicating a less rigid environment for this molecule in the solid state.