title: Paramagnetic relaxation enhancement reveals oligomerization interface of a membrane protein.
abstract: Protein-protein interactions play critical roles in cellular function and oligomerization of membrane proteins is a commonly observed phenomenon. Determining the oligomerization state and defining the intermolecular interface in the bilayer is generally a difficult task. Here, we use site-specific spin labeling to demonstrate that relaxation enhancements induced by covalently attached paramagnetic tag can provide distance restraints defining the intermonomer interface in oligomers formed by a seven-helical transmembrane protein Anabaena Sensory Rhodopsin (ASR). We combine these measurements with visible CD spectroscopy and cross-linking experiments to demonstrate that ASR forms tight trimers in both detergents and lipids.
authors.affiliation: Department of Physics, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Shenlin
authors.initials: S
authors.lastname: Wang
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Munro
authors.forename: So Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Kwang-Hwan
authors.initials: KH
authors.lastname: Jung
authors.forename: Leonid S
authors.initials: LS
authors.lastname: Brown
authors.forename: Vladimir
authors.initials: V
authors.lastname: Ladizhansky
mesh_terms: D017033:Anabaena / Q000737:chemistry*; D025603:Sensory Rhodopsins / Q000737:chemistry*
chemical_list: D025603:Sensory Rhodopsins