Diffusion coefficient of Venus YFP in cytoplasm
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| Value | 8 µm^2/s Range: +4/-2 µm^2/s |
|---|---|
| Organism | Bacteria Escherichia coli |
| Reference | Elf J, Li G, Xie XS. 2007. Probing transcription factor dynamics at the single-molecule level in a living cell. Science May 25 316:1191–94 Supporting Online Material pp 5PubMed ID17525339 |
| Method | Fluorescence Correlation Spectroscopy (FCS) experiment-The Venus protein is expressed from the low copy number plasmid. An Argon ion laser is used as excitation source, an avalanche photodiode (APD) by Perkin-Elmer with 0.1 mm active area diameter was used as a detector for fluorescence correlation spectroscopy, The APD is mounted at the side port of an Olympus IX71 inverted microscope. A 50 mm planoconvex lens is used to further expand the image such that the projection of the diffraction-limited excitation spot in the image plane fills the active area of APD. The size of the detection volume is determined by recording fluorescence autocorrelation function of 10 nM Rhodamine dissolved in water under the same alignment. The estimated waist of detection volume is about w = 294 nm. To monitor the positions of the cells and the excitation spot, a CCD camera (Cascade 512B, Photometrics) is mounted on the side port of the eyepiece. |
| Comments | Free author manuscript available at PUBMED. The diffusion constant of free Venus is estimated to be D3=8 +4/-2µm^2/s. This is also in good agreement with Elowitz et al. (BNID 100193). For diffusion rate of 40kDa dextran in cytoplasm see BNID 100198. |
| Entered by | Uri M |
| ID | 105477 |