MOLECULAR REACTION-MECHANISMS OF PROTEINS MONITORED BY NANOSECOND STEP-SCAN FT-IR DIFFERENCE SPECTROSCOPY

Step-scan FT-IR difference spectroscopy with 100-ns time resolution is applied to the membrane protein bacteriorhodopsin. The experimetal se tup and data acquisition are described in great detail. The IR absorba nce changes accompanying bacteriorhodopsin's photocycle are presented in a three-dimensional representation. The data quality allows one, fo r example, to resolve the biphasic rise of the photocycle-intermediate M. A bacteriorhodopsin's proton pump model based on the FT-IR works i s presented.