title: Expression and purification of membrane proteins.
abstract: Approximately 30% of a genome encodes for membrane proteins. They are one of the most important classes of proteins in that they can receive, differentiate, and transmit intra- and intercellular signals. Some examples of classes of membrane proteins include cell-adhesion molecules, translocases, and receptors in signaling pathways. Defects in membrane proteins may be involved in a number of serious disorders such as neurodegenerative diseases (e.g., Alzheimer's) and diabetes. Furthermore, membrane proteins provide natural entry and anchoring points for the molecular agents of infectious diseases. Thus, membrane proteins constitute ~50% of known and novel drug targets. Progress in this area is slowed by the requirement to develop methods and procedures for expression and isolation that are tailored to characteristic properties of membrane proteins. A set of standard protocols for the isolation of the targets in quantities that allow for the characterization of their individual properties for further optimization is required. The standard protocols given below represent a workable starting point. If optimization of yields is desired, a variation of conditions as outlined in the theory section is recommended.
authors.affiliation: QIAGEN GmbH, Research and Development, Hilden, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Kubicek
authors.affiliation: QIAGEN GmbH, Research and Development, Hilden, Germany.
authors.forename: Helena
authors.initials: H
authors.lastname: Block
authors.affiliation: QIAGEN GmbH, Research and Development, Hilden, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Maertens
authors.affiliation: QIAGEN GmbH, Research and Development, Hilden, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Spriestersbach
authors.affiliation: Institute of Structural Biology and Biophysics (ISB-2), Research Center Juelich, Juelich, Germany. Electronic address: j.Labahn@fz-juelich.de.
authors.forename: Jörg
authors.initials: J
authors.lastname: Labahn
mesh_terms: D015153:Blotting, Western; D002846:Chromatography, Affinity / Q000379:methods*; D003902:Detergents; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics / Q000302:isolation & purification*; D015202:Protein Engineering / Q000295:instrumentation / Q000379:methods*; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012995:Solubility
chemical_list: D003902:Detergents; D008565:Membrane Proteins; D011994:Recombinant Proteins
keywords: Cell-free expression systems; E. coli; Eukaryotic cells; Membrane proteins; Ni-NTA Superflow; Optimal solubilization; Prokaryotic cells