Lipid cubic phase

Landau E M, Rummel G, Cowan-Jacob S W and Rosenbusch J P 1997 Crystallization of a polar protein and small molecules from the aqueous compartment of lipidic cubic phases J. Phys. Chem. B 101 1935-7... 

A continuous lipidic cubic phase is obtained by mixing a long-chain lipid such as monoolein with a small amount of water. The result is a highly viscous state where the lipids are packed in curved continuous bilayers extending in three dimensions and which are interpenetrated by communicating aqueous channels. Crystallization of incorporated proteins starts inside the lipid phase and growth is achieved by lateral diffusion of the protein molecules to the nucleation sites. This system has recently been used to obtain three-dimensional crystals 20 x 20 x 8 pm in size of the membrane protein bacteriorhodopsin, which diffracted to 2 A resolution using a microfocus beam at the European Synchrotron Radiation Facility. 

Landau, E.M., Rosenbuch, J.R Lipid cubic phases a concept for the crystallization of membrane proteins. 

Landau, E. M. and Luisi, P. L. (1993). Lipid cubic phases as transparent, rigid matrices for the direct spectroscopic study of immobilized membrane proteins. J. Am. Chem. 

Pebay-Peyroula, E., Rummel, G., Rosenbusch, IP. and Landau E.M. X-ray structure of bacteri-orhodopsin at 2.5 angstroms from microcrystals grown in lipidic cubic phases (1997) Science 277, 1676-1681... 

The lipidic cubic phase has recently been demonstrated as a new system in which to crystallize membrane proteins [143, 144], and several examples [143, 145, 146] have been reported. The molecular mechanism for such crystallization is not yet clear, but the interfacial water and transport are believed to play an important role in nucleation and crystal growth [146, 147], Using a related model system of reverse micelles, drastic differences in water behavior were observed both experimentally [112, 127, 128, 133-135] and theoretically [117, 148, 149]. In contrast to the ultrafast motions of bulk water that occurs in less than several picoseconds, significantly slower water dynamics were observed in hundreds of picoseconds, which indicates a well-ordered water structure in these confinements. 

Landau, E. M., and Rosenbusch, J. P. (1996). Lipidic cubic phases a novel concept for the crystallization of membrane proteins. Proc. Natl. Acad. Sci. USA 93, 14532-14535. 

Rummel G, Hardmeyer A, Widmer C, Chiu ML, Nollert P, Locher KP, Pedruzzi I, Landau EM, Rosenbusch JP. Lipidic cubic phases new matrices for the three-dimensional crystallization of membrane proteins. J. Struct. Biol. 1998 121 82-91. 

Lipid cubic (51) and sponge (52) phases, as well as bicelles (53), are alternatives to detergents that have been applied successfully to membrane protein crystallization. In these instances, the protein is embedded in a lipid bilayer environment, which is considered more natural compared with the detergents that form micellar phases. In the recent high-resolution crystal structure of the human 32 adrenergic G-protein-coupled receptor, lipid cubic phase was used with necessary cholesterol and 1,4-butandiol additives (54). The cholesterol and lipid molecules were important in facilitating protein-protein contacts in the crystal. 

Gordeliy VI, Schlesinger R, Efremov R, Buldt G, Heberle J. Crystallization in lipidic cubic phases a case study with bacte-riorhodopsin. Methods Molec. Biol. 2003 228 305-316. 

Boyle-Roden E, Hoefer N, Dey KK, Grandinetti PJ, and Caffrey M. High resolution H NMR of a lipid cubic phase using 52. a solution NMR probe. J. Magn. Reson. 2007 189 13-19. 

A cryo-electron diffraction structure " and the structure from bicelle crystal-lization were most compatible with our data while the high-resolution (1.55 A) XRD structure of a crystal grown from a lipidic cubic phase was less compatible. 

Clogston J, Caffrey M. Controlling release from the lipidic cubic phase. Amino acids, peptides, proteins and nucleic acids. Journal of Controlled Release. 2005 107(1) 97-111. 

J. Bender, M.B. Ericson, N. Merclin, V. lani, A. Rosen, S. Engstrom, J. Moan, Lipid cubic phases for improved topical drug delivery in photodynamic therapy. J. Control. Rel. 106, 350-360 (2005)... 

Rowinski, P. and R. Bilewicz (2001). Carbon dioxide electrochemical sensor based on lipid cubic phase containing tetraazamacrocyclic complexes of Ni(II). Materials Science and Engineering C 18(1-2), 177-183. 

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