STRUCTURAL AND FUNCTIONAL INTEGRITY OF THE PHOTOSYSTEM-II REACTION-CENTER ON SILVER ELECTRODES - FLUORESCENCE AND REDOX PROBES

Two simple and sensitive methods have been developed to assess the str uctural and functional integrity of isolated photosystem II reaction c enters deposited on a roughened Ag electrode. Surface-enhanced resonan ce Raman scattering (SERRS) spectra useful for ascertaining structural information can be obtained from biological materials with this techn ique. The first method presented is based on observing differences in the fluorescence emission properties of reaction centers; these depend on the activity of the material. The second is based on the observati on of changes in Raman bands that are sensitive to the redox state of cytochrome b(559) present in the reaction center complex. It is conclu ded that the conditions used here to obtain SERRS spectra do not affec t the structural or functional integrity of the isolated photosystem I I reaction center complex. In principle these approaches also could be used with other chromoproteins.