title: Förster resonance energy transfer as a probe of membrane protein folding.
abstract: The folding reaction of a β-barrel membrane protein, outer membrane protein A (OmpA), is probed with Förster resonance energy transfer (FRET) experiments. Four mutants of OmpA were generated in which the donor fluorophore, tryptophan, and acceptor molecule, a naphthalene derivative, are placed in various locations on the protein to report the evolution of distances across the bilayer and across the protein pore during a folding event. Analysis of the FRET efficiencies reveals three timescales for tertiary structure changes associated with insertion and folding into a synthetic bilayer. A narrow pore forms during the initial stage of insertion, followed by bilayer traversal. Finally, a long-time component is attributed to equilibration and relaxation, and may involve global changes such as pore expansion and strand extension. These results augment the existing models that describe concerted insertion and folding events, and highlight the ability of FRET to provide insight into the complex mechanisms of membrane protein folding. This article is part of a Special Issue entitled: Membrane protein structure and function.
authors.affiliation: Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, CA 92093, USA.
authors.forename: Guipeun
authors.initials: G
authors.lastname: Kang
authors.forename: Ignacio
authors.initials: I
authors.lastname: López-Peña
authors.forename: Vanessa
authors.initials: V
authors.lastname: Oklejas
authors.forename: Cyril S
authors.initials: CS
authors.lastname: Gary
authors.forename: Weihan
authors.initials: W
authors.lastname: Cao
authors.forename: Judy E
authors.initials: JE
authors.lastname: Kim
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D007700:Kinetics; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D017510:Protein Folding
chemical_list: D001425:Bacterial Outer Membrane Proteins; D008565:Membrane Proteins; C078167:OMPA outer membrane proteins