Active membranes studied by X-ray scattering.
In view of recent theories of "active" membranes, we have studied multilamellar phospholipid membrane stacks with reconstituted transmembrane protein bacteriorhodopsin (BR) under different illumination conditions by X-ray scattering. The light-active protein is considered as an active constituent which drives the system out of equilibrium and is predicted to change the collective fluctuation properties of the membranes. Using X-ray reflectivity, X-ray non-specular (diffuse) scattering, and grazing incidence scattering, we find no detectable change in the scattering curves when changing the illumination condition. In particular the intermembrane spacing d remains constant, after eliminating hydration-related artifacts by design of a suitable sample environment. The absence of any observable non-equilibrium effects in the experimental window is discussed in view of the relevant parameters and recent theories.
Giahi
A
A
Institut für Röntgenphysik, Friedrich-Hund-Platz 1, 37073, Göttingen, Germany. agiahi@gwdg.de
El Alaoui Faris
M
M
Bassereau
P
P
Salditt
T
T
D001436:Bacteriorhodopsins / Q000737:chemistry* / Q000378:metabolism; D001703:Biophysics / Q000379:methods*; D004583:Electrons; D004867:Equipment Design; D006217:Halobacterium / Q000378:metabolism; D006813:Humidity; D008051:Lipid Bilayers / Q000737:chemistry*; D008968:Molecular Conformation; D009502:Neutrons; D010713:Phosphatidylcholines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry*; D011485:Protein Binding; D018717:Purple Membrane / Q000378:metabolism; D012542:Scattering, Radiation; D014965:X-Rays
D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D010743:Phospholipids; D001436:Bacteriorhodopsins
Phys Rev Lett. 2006 Jul 28;97(4):048103
16907615
Phys Rev Lett. 2000 Apr 10;84(15):3494-7
11019123
Biophys J. 2003 Sep;85(3):1576-84
12944274
Phys Rev E Stat Nonlin Soft Matter Phys. 2002 Sep;66(3 Pt 1):031914
12366159
Annu Rev Biophys Biomol Struct. 1999;28:367-99
10410806
Biophys J. 2000 Jun;78(6):3208-17
10827997
Phys Rev Lett. 2003 May 2;90(17):178101
12786106
Phys Rev Lett. 2005 Mar 4;94(8):088101
15783938
Biophys J. 2004 Jul;87(1):419-29
15240476
Nat New Biol. 1971 Sep 29;233(39):149-52
4940442
Eur Phys J E Soft Matter. 2003 Oct;12(2):283-90
15007664
Phys Rev Lett. 2004 Dec 31;93(26 Pt 1):268104
15698026
Methods Enzymol. 1974;31:667-78
4418026
Phys Rev Lett. 2004 Apr 23;92(16):168101
15169263
Phys Rev E Stat Nonlin Soft Matter Phys. 2001 Aug;64(2 Pt 1):021908
11497621
Eur Phys J E Soft Matter. 2006 Jun;20(2):221-30
16802069
J Biol Chem. 2002 Oct 18;277(42):39304-11
12167614