Lateral mobility of peptides
and proteins
in bilayers
![](saffman2.bmp)
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 µw of the bounding fluid : we
studied the effects of sugars, dextran, or PEGs on membranes.
Based on our data, as well as literature, we proved
that Saffman-Delbruck formula does not describe correctly the experimental
results,
and therefore we propose an heuristic law as well as a possible
theoritical model ( with N. GOV, ISRAEL)
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