Volume of ribosome

Range S. cerevisiae ~4.34×10^6Å^3: E. coli ~3.4×10^6Å^3 Å^3
Organism Various
Reference Verschoor A, Warner JR, Srivastava S, Grassucci RA, Frank J. Three-dimensional structure of the yeast ribosome. Nucleic Acids Res. 1998 Jan 15 26(2):655-61. p.656 left column bottom paragraphPubMed ID9421530
Method p.656 left column 4th paragraph:"The 80S ribosome from S.cerevisiae has been reconstructed from 7470 individual ribosome images to a resolution of 35 Å according to the Fourier Shell Criterion measure, using a critical value of 0.5 (ref 14), corresponding to a signal-to-noise ratio of ~2 (ref 15). This value closely agreed with the value obtained by the 45° phase residual criterion used in previous studies. Low pass filtration to 35 Å and, for correction of the transfer function, Wiener filtration were then applied."
Comments "At the threshold used for surface representation (e.g. Fig. 1) the volume of the yeast ribosome reconstruction is calculated to be ~4.34 × 10^6 Å^3. This figure may be compared with a volume of 3.4 × 10^6 Å^3 for the E.coli ribosome (at 25 Å resolution) visualized at an analogous threshold. These volume estimates are significantly higher than those obtained from simple summation of the molecular masses of the rRNA and ribosomal proteins: 2.6 × 10^6 Å^3 for E.coli (ref 16) and 3.41 × 10^6 Å^3 for yeast [calculated from mass data given in (ref 17) and the RNA/protein ratios given above see Introduction]. The choice of threshold relative to the calculated theoretical mass of the components was made to enable direct comparison with the published E.coli structures (refs 18,19). However, the volume estimate that corresponds to a given threshold is extremely sensitive to several factors, among which is uncertainty in the electron microscopic magnification (ref 16). As discussed by Frank and Agrawal (ref 20), the appropriate choice of threshold should rather be based on innate criteria such as contiguity of the mass."
Entered by Uri M
ID 111543