Molecular reaction mechanisms of proteins monitored by time-resolved FTIR-spectroscopy.

Time-resolved FTIR difference spectroscopy can provide a valuable insight into the molecular reaction mechanisms of proteins, especially membrane proteins. Isotopic labeling and site-directed mutagenesis allows an unequivocal assignment of IR absorption bands. Studies are presented which give insight into the proton pump mechanisms of proteins, especially bacteriorhodopsin. H-bonded network proton transfer via internal water molecules seems to be a general feature in proteins, also found in cytochrome c oxidase. Using caged GTP the intrinsic and GAP catalyzed GTPase activity of H-ras p21 is studied. Furthermore, protein folding reactions can be recorded with ns time-resolution.