DIRECT RECONSTITUTION OF BACTERIORHODOPSIN INTO PLANAR PHOSPHOLIPID-BILAYERS - DETERGENT EFFECT

This paper describes how the structure and concentration level of a de tergent used for substitution after bacteriorhodopsin (bR) solubilizat ion affect the reconstitution of the bR into phospholipid planar bilay ers, A direct insertion method was used for the bR reconstitution into the bilayers. Two detergents representing the two major types were us ed: sodium deoxycholate with a cholane-ring structure, and octylglucos ide with a linear (or chain) structure. We then characterized the reco nstitution for the two detergents by considering the detergent separat ion profiles and the photocurrent variations upon addition of lanthanu m chloride and the protonophore FCCP arbonylcyanide-p-trifluoromethoxy phenylhydrazone). We found that for successful transmembrane reconstit ution of bR the detergent with the cholane-ring structure was preferab le to that with the linear structure when the detergent concentration was above its critical micellar concentration. This preference was exp lained by the ease with which the detergent with the cholane-ring stru cture was removed from protein compared to that with the linear struct ure. Finally, we proposed a scheme for the reconstitution of the prote in.