Stretched exponential decay and correlations in the catalytic activity of fluctuating single lipase molecules

Flomenbom, Ophir, Velonia, Kelly, Loos, Davey, Masuo, Sadahiro, Cotlet, Mircea, Engelborghs, Yves, Hofkens, Johan, Rowan, Alan E., Nolte, Roeland J. M., Van der Auweraer, Mark, de Schryver, Frans C. and Klafter, Joseph (2005) Stretched exponential decay and correlations in the catalytic activity of fluctuating single lipase molecules. Proceedings of the National Academy of Sciences , 102 7: 2368-2372. doi:10.1073/pnas.0409039102


Author Flomenbom, Ophir
Velonia, Kelly
Loos, Davey
Masuo, Sadahiro
Cotlet, Mircea
Engelborghs, Yves
Hofkens, Johan
Rowan, Alan E.
Nolte, Roeland J. M.
Van der Auweraer, Mark
de Schryver, Frans C.
Klafter, Joseph
Title Stretched exponential decay and correlations in the catalytic activity of fluctuating single lipase molecules
Journal name Proceedings of the National Academy of Sciences    Check publisher's open access policy
ISSN 0027-8424
1091-6490
Publication date 2005-02-15
Year available 2005
Sub-type Article (original research)
DOI 10.1073/pnas.0409039102
Open Access Status Not yet assessed
Volume 102
Issue 7
Start page 2368
End page 2372
Total pages 5
Place of publication Washington, DC, United States
Publisher National Academy of Sciences
Language eng
Abstract Single-molecule techniques offer a unique tool for studying the dynamical behavior of individual molecules and provide the possibility to construct distributions from individual events rather than from a signal stemming from an ensemble of molecules. In biological systems, known for their complexity, these techniques make it possible to gain insights into the detailed spectrum of molecular conformational changes and activities. Here, we report on the direct observation of a single lipase-catalyzed reaction for extended periods of time (hours), by using confocal fluorescence microscopy. When adding a profluorescent substrate, the monitored enzymatic activity appears as a trajectory of "on-state" and "off-state" events. The waiting time probability density function of the off state and the state-correlation function fit stretched exponentials, independent of the substrate concentration in a certain range. The data analysis unravels oscillations in the logarithmic derivative of the off-state waiting time probability density function and correlations between off-state events. These findings imply that the fluctuating enzyme model, which involves a spectrum of enzymatic conformations that interconvert on the time scale of the catalytic activity, best describes the observed enzymatic activity. Based on this model, values for the coupling and reaction rates are extracted.
Keyword Single enzyme activity
Two-state trajectories
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Australian Institute for Bioengineering and Nanotechnology Publications
 
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