Lateral mobility of peptides

and proteins in bilayers

 We wanted to verify the accuracy of Saffman-Delbruck model, (formula above), widely used to analyze lateral mobility in membranes.

We labeled and reconstituted transmembrane proteins ( OmpA, OprM, BR) in Giant Unilamellar Vesicles or in model bilayers of tunable thickness.

We successively checked the dependence of the diffusion coefficient D in :

                     the radius R of the diffusing object,

                the thickness h of the membrane,

                and the importance of the viscosity µ_w of the bounding fluid : we studied the effects of sugars, dextran, or PEGs on membranes.

and therefore we propose an heuristic law as well as a possible theoritical model ( with N. GOV, ISRAEL)