SYNTHESIS OF NITROXIDE CONTAINING POLYENES - 2 CHEMICALLY-MODIFIED RETINALS AND THEIR INTERACTION WITH BACTERIORHODOPSIN

The synthesis and spectroscopic characterization of two retinal analog ues is described, the paramagnetic 3-pyrrolin-1-yloxy analogue 1 and i ts diamagnetic equivalent, the 3-pyrroline analogue 2. Various aspects of the synthesis of the aminoxy group containing polyenes are discuss ed. Upon interaction with bacterioopsin, both 1 and 2 are incorporated in the protein and form a system with lambda(max) 459 nm. Neither of the two bacteriorhodopsin analogues is photoactive. ESR spectroscopy d ata of the system containing 1 show that the ring part of the chromoph ore in the protein is rigidly fixed in orientation.