ATR-FTIR spectroscopy of membrane-bound Ras protein

The first high quality Amide I bands of membrane-bound Ras were obtained after establishing an ATR-FTIR set-up. Protein secondary structure analyses were performed by an improved curve-fitting technique. Truncated H-Ras (1-166) and membrane-bound N-Ras (1-188) protein secondary structures were in accordance with the literature. Tyr side chain band splitting was observed for the membrane-bound N-Ras. Besides, secondary structure deviations were apparent, when there was no membrane available to the protein for binding. Measurements were also performed with the polarized light. The study of membrane-bound Ras protein interaction with the nitric oxide was initiated in a model system. Protein activity was attained. The lipid absorption intensity was modulated. In relation, random to sheet transitions of the membrane-bound Ras protein was observed. Stabilizing interactions of the lipid C=O region were accompanying. This could be associated with the conformational changes in the Ras protein