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Isotropic diffusion of the small ribosomal subunit in Escherichia coli
- Publication Year :
- 2012
-
Abstract
- The ribosome is one of the most important macromolecular complexes in a living cell. We have tracked individual 30S ribosomal subunits in exponentially growing E. coli cells using three-dimensional single-particle tracking, where the z-position is estimated using astigmatism. The 30S subunits are stochiometrically labeled with S2-mEos2 by replacing the rpsB gene in the E. coli chromosome by rpsB-mEos2. The spatial precision in tracking is 20 nm in xy and 70 nm in z. The average trajectory consists of 4 steps corresponding to 80 ms. The trajectories are excluded from parts of the cell, consistent with nucleoid exclusion, and display isotropic diffusion with nearly identical apparent diffusion coefficients (0.05 +/- 0.01 um^2/s) in x, y and z. The tracking data fits well to a two-state diffusion model where 46% of the molecules are diffusing at 0.02 um^2/s and 54% are diffusing at 0.14 um^2/s. These states could correspond to translating 70S ribosomes and free 30S subunits.<br />Comment: 5 pages, 5 figures
- Subjects :
- Quantitative Biology - Quantitative Methods
Physics - Biological Physics
Subjects
Details
- Database :
- arXiv
- Publication Type :
- Report
- Accession number :
- edsarx.1205.5857
- Document Type :
- Working Paper