| | Science@Berkeley Lab: Ratcheting, Swiveling, Opening the Groove |
 | | The structure reveals how the ribosome "head" moves while making proteins specified by messenger RNA (mRNA), shuttling transfer RNAs (tRNAs) from site A to site P to site E. Ribosomes are unusual cellular machines in that they are not made mostly of proteins; instead, two-thirds of the ribosome consists of a special form of RNA. |
 | | Detailed structures of the ribosome's two main components have been created in recent years, but these are a little like having the plans for two halves of a car without knowing how they fit together. |
 | | Since the ribosome's own RNA is infused with magnesium ions and is highly charged, the salt water may act as a kind of "lubricant," locally neutralizing the charge between the subunits to allow them to move in relation to each other and allow tRNAs to slide through the gap. |
| www.lbl.gov /Science-Articles/Archive/sabl/2005/November/ribosome-groove.html (1738 words) |