title: Protein conformational dynamics probed by single-molecule electron transfer.
abstract: Electron transfer is used as a probe for angstrom-scale structural changes in single protein molecules. In a flavin reductase, the fluorescence of flavin is quenched by a nearby tyrosine residue by means of photo-induced electron transfer. By probing the fluorescence lifetime of the single flavin on a photon-by-photon basis, we were able to observe the variation of flavin-tyrosine distance over time. We could then determine the potential of mean force between the flavin and the tyrosine, and a correlation analysis revealed conformational fluctuation at multiple time scales spanning from hundreds of microseconds to seconds. This phenomenon suggests the existence of multiple interconverting conformers related to the fluctuating catalytic reactivity.
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Haw
authors.initials: H
authors.lastname: Yang
authors.forename: Guobin
authors.initials: G
authors.lastname: Luo
authors.forename: Pallop
authors.initials: P
authors.lastname: Karnchanaphanurach
authors.forename: Tai-Man
authors.initials: TM
authors.lastname: Louie
authors.forename: Ivan
authors.initials: I
authors.lastname: Rech
authors.forename: Sergio
authors.initials: S
authors.lastname: Cova
authors.forename: Luying
authors.initials: L
authors.lastname: Xun
authors.forename: X Sunney
authors.initials: XS
authors.lastname: Xie
mesh_terms: D019943:Amino Acid Substitution; D002384:Catalysis; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003198:Computer Simulation; D004583:Electrons; D004926:Escherichia coli / Q000201:enzymology; D038181:FMN Reductase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005486:Flavin Mononucleotide / Q000737:chemistry* / Q000378:metabolism; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry* / Q000378:metabolism; D005415:Flavins; D005453:Fluorescence; D006860:Hydrogen Bonding; D016013:Likelihood Functions; D008433:Mathematics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D017785:Photons; D011487:Protein Conformation; D012694:Serine; D013050:Spectrometry, Fluorescence; D013696:Temperature; D013816:Thermodynamics; D014443:Tyrosine
chemical_list: D005415:Flavins; D005182:Flavin-Adenine Dinucleotide; D014443:Tyrosine; D012694:Serine; C008173:isoalloxazine; D005486:Flavin Mononucleotide; D038181:FMN Reductase