DIRECTLY PROBING RAPID MEMBRANE-PROTEIN DYNAMICS WITH AN ATOMIC-FORCEMICROSCOPE - A STUDY OF LIGHT-INDUCED CONFORMATIONAL ALTERATIONS IN BACTERIORHODOPSIN

This paper demonstrates that an atomic force microscope can be used to directly monitor rapid membrane protein dynamics. For this demonstrat ion the membrane-bound proton pump, bacteriorhodopsin, has been invest igated, It has been unequivocally shown that the light-induced dynamic alterations that have been observed do not arise from external artifa cts such as heating of the sample by the incident light, but that thes e changes can be directly linked to the light-induced protein conforma tional alterations in this membrane. In essence, it has been shown tha t the light energy absorbed by bacteriorhodopsin is converted not only to chemical energy but also to mechanical energy, In summary a new ul trasensitive tool is described for monitoring the molecular dynamics o f materials with wide applicability to fundamental and applied science .