Relaxation times monomeric exchange

Neutron diffraction of samples with added deuterated water [130], as well as hydrogen exchange studies [118], suggest that no aqueous channels exist between the protein molecules in purple membranes, or between the helices, i.e., the lipids completely fill the spaces. As expected from the crystalline structure and the relatively low lipid/protein ratio, the packing of protein in purple membrane is quite rigid, and the mobility of the protein in the lattice appears low, as determined by flash dichroism [131,132]. On the other hand, bacteriorhodopsin incorporated into liposomes at high lipid/protein ratios exists as a monomeric molecule [133], and shows rapid rotation by this criterion (relaxation time 15 /us) above the phase... 

Dilute micellar solutions of surfactants are characterized by two well-separated relaxation times. The molecular origin of the fast relaxation time has been related to a monomer-micelle exchange [181-184]. It was realized later that the relaxation spectra of micellar solutions really exhibit two relaxation times. The theory of Aniansson and Wall [167,185] assumes a stepwise aggregation of surfactant monomers to form micelles [186]. The fast relaxation time is attributed to the exchange of monomeric surfactants between the micelles and the intermicel-lar solution. The slow relaxation time is attributed to micelle formation and breakdown. The theory and its modifications by Kahlweit and co-workers [170-174]... 

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