ISSN:
1432-1017
Keywords:
Key words Purple membrane
;
Disk membrane
;
Quasielastic incoherent neutron scattering
;
Lamellar structure
;
Diffusive motions
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Physics
Notes:
Abstract Fast stochastic equilibrium fluctuations (time scale: 10–10–10–13 seconds) in purple membranes (PM) and in disk membranes (DM) have been measured with quasielastic incoherent neutron scattering. The comparison of predominantly stochastic motions occurring in purple membranes and in disk membranes revealed qualitatively similar dynamical behaviour. Models of internal motions within restricted volumes have been shown to be useful to fit the spectra from both samples. From fits using these models we found “amplitudes” 15 to 20% larger for motions in DM samples compared to PM samples. This indicates a higher internal flexibility of the DM. Because the dynamical behaviour is very sensitive to the hydration of the protein-lipid complex, we also performed neutron diffraction experiments to determine lamellar spacings as a measure of level of hydration and as a function of temperature. From these studies the interaction of solvent molecules with the surface of the protein-lipid complex appears to be qualitatively similar for both types of membranes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002490050175
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