| Value |
22
nm
Range: ±2 nm
|
| Organism |
Bacteria Escherichia coli |
| Reference |
Brandt F, Etchells SA, Ortiz JO, Elcock AH, Hartl FU, Baumeister W. The native 3D organization of bacterial polysomes. Cell. 2009 Jan 23 136(2):261-71. p.264 right column top paragraphPubMed ID19167328
|
| Method |
Researchers employed cryoelectron tomography and a template-matching approach to map 70S ribosomes in vitrified bacterial translation extracts and in lysates of active E. coli spheroplasts. The spatial orientation of ribosomes in polysomes was determined
by 3D template matching with a resolution-adjusted
density derived from a 70S ribosome reference structure (Schuwirth
et al., 2005). Particle coordinates and orientations in relation
to the reference (Figure S3) were extracted from peaks in
the resulting 3D crosscorrelation function (see Experimental
Procedures). |
| Comments |
Distance vectors from the center of mass of
each identified polysomal ribosome to the center of mass of its
closest neighbor particle clearly indicated preferential positioning
at a distance around 22±2 nm. Researchers' analysis reveals a remarkably well defined
arrangement of ribosomes in staggered or helical orientations,
with the mRNA being sequestered on the inside, while
the tRNA entrance sites and the polypeptide exit sites are
exposed to the cytosol. See BNID 105001. Note-Martin and Miller 1983, PMID 6683685 p. 345 right column 2nd paragraph write that a ribosome binds every ~135 nts in sea urchin polysome |
| Entered by |
Uri M |
| ID |
105000 |