Protein conformational dynamics probed by single-molecule electron transfer.
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.
Yang
Haw
H
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
Luo
Guobin
G
Karnchanaphanurach
Pallop
P
Louie
Tai-Man
TM
Rech
Ivan
I
Cova
Sergio
S
Xun
Luying
L
Xie
X Sunney
XS
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
D005415:Flavins; D005182:Flavin-Adenine Dinucleotide; D014443:Tyrosine; D012694:Serine; C008173:isoalloxazine; D005486:Flavin Mononucleotide; D038181:FMN Reductase