Differences between the structural dynamics of plasma membranes of normal hamster lymphocytes and lymphoid cells neoplastically transformed by simian virus 40 as revealed by laser Raman spectroscopy.

Abstract

The Raman spectra of highly purified plasma membranes from SV40-transformed GD248 lymphocytes have been compared with the spectra of the membranes of normal cells over the spectral region 100 cm-1 to 3010 cm-1. Striking differences between the two membrane categories were observed in the thermal response of the CH-stretching and acoustical regions. Analysis of CH-stretching shows that the membranes of normal cells exhibit a thermal transition centered at 7 degrees and approximately 5 degrees wide. The membranes of GD248 cells, in contrast, show a lipid transition centered at -5 degrees and 12-18 degrees wide. Analysis of the acoustical region yields equivalent results. The membrane proteins of normal membranes undergo a large thermotropic transition, starting at 39 degrees (sample temperatures), whereas this transition begins at 23 degrees with GD248 plasma membranes. The results suggest the possibility that SV40-specific membrane proteins may modify the collective thermotropic behavior of both normal membrane proteins and membrane lipids.