title: The effect of increasing concentrations of precipitating salts used to crystallize proteins on the structure of the lipidic Q224 cubic phase.
abstract: A major obstacle to elucidating the structure of membrane proteins at high resolution is the difficulty of preparing these proteins as well as to grow well-ordered crystals. During the last few years several groups have considered the use of three-dimensional bicontinuous lipidic cubic phases as a possible crystallization matrix for such molecules. In a few cases these studies have been successfully approached by other laboratories, however, a number of questions remain, particularly in regard to the effects of solutes on the phase diagrams of lipid-water systems. In the present work we report the structural behavior of the lipidic Q224 (Pn3m), Q230 (Ia3d) and HII phases systematically studied in the presence of a range of concentrations of various salts and precipitating agents at various pH values. Some of the results reported here have been presented elsewhere Vargas et al. (2000) [Strategies in membrane protein crystallization. Chemical Prospectives in Crystallography of Molecular Biology. International School of Crystallography, NATO-ASI course, Erice (Italy)].
authors.affiliation: Departamento de Biología Estructural, Instituto Venezolano de Investigaciones Científicas, Aptdo. 21827, Caracas1020-A, Venezuela.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Vargas
authors.forename: Leonardo
authors.initials: L
authors.lastname: Mateu
authors.forename: Antonio
authors.initials: A
authors.lastname: Romero
mesh_terms: D003460:Crystallization; D003902:Detergents / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry*; D044367:Phase Transition; D012492:Salts / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D003902:Detergents; D008055:Lipids; D012492:Salts