Protein conformational dynamics probed by single-molecule electron transfer

Science. 2003 Oct 10;302(5643):262-6. doi: 10.1126/science.1086911.

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.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Substitution
  • Catalysis
  • Chemical Phenomena
  • Chemistry, Physical
  • Computer Simulation
  • Electrons
  • Escherichia coli / enzymology
  • FMN Reductase / chemistry*
  • FMN Reductase / genetics
  • FMN Reductase / metabolism
  • Flavin Mononucleotide / chemistry*
  • Flavin Mononucleotide / metabolism
  • Flavin-Adenine Dinucleotide / chemistry*
  • Flavin-Adenine Dinucleotide / metabolism
  • Flavins
  • Fluorescence
  • Hydrogen Bonding
  • Likelihood Functions
  • Mathematics
  • Models, Molecular
  • Mutagenesis, Site-Directed
  • Photons
  • Protein Conformation
  • Serine
  • Spectrometry, Fluorescence
  • Temperature
  • Thermodynamics
  • Tyrosine

Substances

  • Flavins
  • Flavin-Adenine Dinucleotide
  • Tyrosine
  • Serine
  • isoalloxazine
  • Flavin Mononucleotide
  • FMN Reductase