CYCLOPENTENE AND CYCLOHEXENE RETINAL ANAL OGS REACT DIFFERENTLY WITH BACTERIOOPSIN

Cyclopentene and cyclohexene analogues of 13-cis-retinal were synthesi zed by the Iotsich condensation of 9-propynil-beta-ionol with the corr esponding cyclo-beta-ketoacetals. In the bacteriorhodopsin resynthesis test these analogues reacted with bacterioopsin in Halobacterium halo bium apomembrane, the cyclopentene 13-cis-retinal analogue, forming th e corresponding bacteriorhodopsin analogue that can undergo photoinduc ed hydrolysis. Interaction of the cyclohexene 13-cis-retinal analogue with bacterioopsin stops at the stage of the non-covalent complex form ation.