In the cytoplasm, ribsomal RNA (rRNA) and protein combine
to form a nucleoprotein called a ribosome. The ribosome serves
as the site and carries the enzymes necessary for protein synthesis.
In the graphic on the left, the ribosome is shown as made from
two sub units, 50S and 30 S. There are about equal parts rRNA
and protein. The far left graphic shows the complete ribosome
with three tRNA attached.
The ribosome attaches itself to m-RNA and provides the stabilizing
structure to hold all substances in position as the protein is
synthesized. Several ribosomes may be attached to a single RNA
at any time. In upper right corner is the 30S sub unit with mRNA
and tRNA attached.
30S Subunit Ribosome - Chime
in new window
Note: The coordinates used in this display have only the alpha
carbons of the proteins (CA) and the DNA backbone atoms.
with 70S Ribosome
with 50S Ribosome
with 30S Ribosome - Dr. William McClure,
Carnegie Mellon University
- Molecule of Month, PDB - several pages, David
Credit: 30S Ribosome: Yusupov, M. M., Yusupova,
G. Z., Baucom, A., Lieberman, K., Earnest, T. N., Cate, J. H.
D., Noller, H. F. (2001) "Crystal structure of the ribosome
at 5.5 Å resolution" Science 292:883.