title: Phase behavior of a designed cyclopropyl analogue of monoolein: implications for low-temperature membrane protein crystallization.
abstract: Lipidic cubic phases (LCPs) are used in areas ranging from membrane biology to biodevices. Because some membrane proteins are notoriously unstable at room temperature, and available LCPs undergo transformation to lamellar phases at low temperatures, development of stable low-temperature LCPs for biophysical studies of membrane proteins is called for. Monodihydrosterculin (MDS) is a designer lipid based on monoolein (MO) with a configurationally restricted cyclopropyl ring replacing the olefin. Small-angle X-ray scattering (SAXS) analyses revealed a phase diagram for MDS lacking the high-temperature, highly curved reverse hexagonal phase typical for MO, and extending the cubic phase boundary to lower temperature, thereby establishing the relationship between lipid molecular structure and mesophase behavior. The use of MDS as a new material for LCP-based membrane protein crystallization at low temperature was demonstrated by crystallizing bacteriorhodopsin at 20 °C as well as 4 °C.
authors.affiliation: Department of Chemistry, University of Zürich, Winterthurerstrasse 190, 8057 Zürich (Switzerland).
authors.forename: Livia
authors.initials: L
authors.lastname: Salvati Manni
authors.forename: Alexandru
authors.initials: A
authors.lastname: Zabara
authors.forename: Yazmin M
authors.initials: YM
authors.lastname: Osornio
authors.forename: Jendrik
authors.initials: J
authors.lastname: Schöppe
authors.forename: Alexander
authors.initials: A
authors.lastname: Batyuk
authors.forename: Andreas
authors.initials: A
authors.lastname: Plückthun
authors.forename: Jay S
authors.initials: JS
authors.lastname: Siegel
authors.forename: Raffaele
authors.initials: R
authors.lastname: Mezzenga
authors.forename: Ehud M
authors.initials: EM
authors.lastname: Landau
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry; D003080:Cold Temperature; D003460:Crystallization; D005989:Glycerides / Q000737:chemistry*; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D044367:Phase Transition; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D005989:Glycerides; D008565:Membrane Proteins; D001436:Bacteriorhodopsins; C005953:monoolein
keywords: lipid synthesis; membrane proteins; mesophases; phase behavior; small-angle X-ray scattering