last updated April 2013
The end of the message
A team of scientists from three continents has combined their expertise to uncover important new insights into the final stages of bacterial protein production
Translation, the process by which messenger RNAs are interpreted as blueprints for protein production, is mediated by cellular complexes called ribosomes. These scan the message, building a string of linked amino acids until it hits a termination signal, at which point it ceases translation and releases the completed chain.
In bacteria, termination requires three release factor proteins: RF1, 2 and 3. RF3 is last to act, releasing RF1 and RF2 and resetting the ribosome to enable translation. The details of this process have remained unclear until recently, when Haiwei Song at the Institute of Molecular and Cell Biology in Singapore, Måns Ehrenberg at Uppsala University in Sweden, and Joachim Frank at the Wadsworth Institute in the US joined forces to build a detailed, experimentally supported model1.
The three groups combined high-resolution physical models derived from sophisticated structural biology techniques with data from experiments measuring the functional effects of various mutations in RF3. Together, these results revealed how RF3 directly induces structural changes in the ribosome that release the other RF proteins.
“The joint efforts and combined expertise from our three labs led to these exciting results,” concludes Song, “[which] deepen our understanding of the molecular mechanism underlying translational termination in prokaryotes.”