'Rhythm' of protein folding encoded in RNA, Stanford biologists find
By Max McClure
30 January 2013
Your average musical melody doesn't chug along at a single, mechanical speed. It mixes whole notes, quarter notes, sixteenth notes and so on to lay out a specific, complex rhythm.
It looks like protein synthesis may work the same way.
The sequence of events is elegant: proteins are assembled when ribosomes match mRNA sequences up with specific tRNA molecules. Those tRNAs carry specific amino acids that link together in a chain to form a specific protein.
But multiple RNA sequences can encode the same amino acid – some that are translated quickly, and some slowly. Although they all result in proteins with identical composition, the choice of mRNA sequence can dramatically change the rate at which the protein is made.
Research from Stanford biology Professor Judith Frydman and researcher Sebastian Pechmann now reveals that this protein synthesis "rhythm" may be evolutionarily adjusted to control the folding of the new protein chain as it emerges from the ribosome.
The finding may explain how RNA sequences define the final, folded form of a protein – a fundamental problem in molecular biology, since proteins need to fold in order to function.