Compositional dependence of spectral features in the Raman spectra of erythrocyte membranes

The Raman spectra of erythrocyte membranes in water and D2O were analyzed to determine the percentage of protein and lipid contributions to the amide I spectral feature. The approach of Lippert et al. [J. Am. Chem. Soc. 98, 7075 (1976)] was modified to use circular dichroism data for protein conformations of erythrocyte membranes to determine the relative lipid and protein contributions to the 1660 cm−1 spectral feature. It was determined that 69 ± 15% of the measured peak intensity was due to the protein contribution. The implication of this data to the quantity of α‐helix conformation in membrane protein of erythrocytes, and alternative approaches to determine protein conformation from Raman spectra are discussed.