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2.2-Angstrom in meso crystal structure of Haloquadratum Walsbyi Bacteriorhodopsin (HwBR) from Octylglucoside (OG) Detergent Micelles
Structural highlights
FunctionBACR1_HALWD Light-driven proton pump. The chromophore contains 78% all-trans- and 22% 13-cis-retinal in the dark and 90% all-trans- and 10% 13-cis-retinal upon illumination with >500 nm light.[1] [2] [3] Publication Abstract from PubMedFor some membrane proteins, detergent-mediated solubilization compromises protein stability and functionality, often impairing biophysical and structural analyses. Hence, membrane-protein structure determination is a continuing bottleneck in the field of protein crystallography. Here, as an alternative to approaches mediated by conventional detergents, we report the crystallogenesis of a recombinantly produced membrane protein that never left a lipid bilayer environment. We used styrene-maleic acid (SMA) copolymers to solubilize lipid-embedded proteins into SMA nanodiscs, purified these discs by affinity and size-exclusion chromatography, and transferred proteins into the lipidic cubic phase (LCP) for in meso crystallization. The 2.0-A structure of an alpha-helical seven-transmembrane microbial rhodopsin thus obtained is of high quality and virtually identical to the 2.2-A structure obtained from traditional detergent-based purification and subsequent LCP crystallization. Crystallogenesis of Membrane Proteins Mediated by Polymer-Bounded Lipid Nanodiscs.,Broecker J, Eger BT, Ernst OP Structure. 2017 Jan 3. pii: S0969-2126(16)30394-X. doi:, 10.1016/j.str.2016.12.004. PMID:28089451[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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