title: Single-molecule enzymatic dynamics.
abstract: Enzymatic turnovers of single cholesterol oxidase molecules were observed in real time by monitoring the emission from the enzyme's fluorescent active site, flavin adenine dinucleotide (FAD). Statistical analyses of single-molecule trajectories revealed a significant and slow fluctuation in the rate of cholesterol oxidation by FAD. The static disorder and dynamic disorder of reaction rates, which are essentially indistinguishable in ensemble-averaged experiments, were determined separately by the real-time single-molecule approach. A molecular memory phenomenon, in which an enzymatic turnover was not independent of its previous turnovers because of a slow fluctuation of protein conformation, was evidenced by spontaneous spectral fluctuation of FAD.
authors.affiliation: Pacific Northwest National Laboratory, William R. Wiley Environmental Molecular Sciences Laboratory, Richland, WA 99352, USA.
authors.forename: H P
authors.initials: HP
authors.lastname: Lu
authors.forename: L
authors.initials: L
authors.lastname: Xun
authors.forename: X S
authors.initials: XS
authors.lastname: Xie
mesh_terms: D001665:Binding Sites; D001951:Brevibacterium / Q000201:enzymology; D002784:Cholesterol / Q000378:metabolism*; D002789:Cholesterol Oxidase / Q000378:metabolism*; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism*; D007700:Kinetics; D008856:Microscopy, Fluorescence; D010084:Oxidation-Reduction; D011336:Probability; D013050:Spectrometry, Fluorescence; D013269:Stochastic Processes
chemical_list: D005182:Flavin-Adenine Dinucleotide; D002784:Cholesterol; D002789:Cholesterol Oxidase