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Internalization and Observation of Fluorescent Biomolecules in Living Microorganisms via Electroporation
Published on: February 8, 2015
Electron transfer reaction in a single protein molecule observed by total internal reflection fluorescence microscopy
Yoshiaki Furukawa1, Tadato Ban, Daizo Hamada
1Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan.
Journal of the American Chemical Society
|February 17, 2005
Summary
Researchers visualized single protein electron transfer (ET) using a fluorescent probe. The study observed blinking fluorescence, revealing ET rate distribution linked to protein structural fluctuations and Marcus theory.
Area of Science:
- Biophysics
- Biochemistry
- Molecular Biology
Background:
- Electron transfer (ET) is crucial in biological processes.
- Observing ET at the single-molecule level provides detailed mechanistic insights.
- Cytochrome b5 (Cytb5) is a key protein involved in electron transport.
Purpose of the Study:
- To develop a model system for visualizing single protein electron transfer.
- To monitor intramolecular electron transfer in a modified cytochrome b5 molecule.
- To investigate the kinetics and distribution of ET rates in single protein molecules.
Main Methods:
- Constructed a model system (Alexa-HCytb5) by modifying Cytb5 with Alexa Fluor 647 dye.
- Utilized single-molecule fluorescence microscopy with total internal reflection illumination.
- Analyzed fluorescence blinking to determine single-molecule ET rate constants.
Main Results:
- Observed intermittent fluorescence blinking of single Alexa-HCytb5 molecules.
- Determined single-molecule ET rate constants ranging from 1 to 10 s(-1).
- Found that the protein ET reaction is characterized by a distribution of rate constants.
Conclusions:
- The developed system enables visualization of ET reactions in single protein molecules.
- The observed distribution of ET rate constants can be explained by protein structural fluctuations.
- Protein structural dynamics, leading to distance changes, are proposed as the origin of ET rate distribution based on Marcus theory.
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