Astrobiologists have revealed new information about the structure of RNA molecules found in the ribosome of cells. The study indicates that long-accepted models of ribosomal RNA (rRNA), which are used to study how ribosomes function, require some major updating.

Previous models indicated that rRNA was built out of 6 separate pieces – known as domains. These six domains were organized around a central core, and the structure of this core was a bit of a mystery. This model of rRNA became an iconic example of the structure and can be found in nearly all biology and biochemistry textbooks. Now, astrobiologists supported by the NASA Astrobiology Institute (NAI) have shown that the central core of the molecule is actually an entirely separate domain.

“It speaks to how complicated the ribosome is, and how difficult it is to understand on a molecular level,” says Dr. Loren Williams, Principle Investigator for the NAI team at Georgia Tech and co-author of the paper. “We worked with it for years without realizing it was wrong.”

rRNA is found in all living cells, but there are slight differences in molecules taken from different species. Studying the similarities and differences provides important clues about how the molecule has evolved throughout the history of life.

Ribosomes have been around for as long as life itself, and act as a mediator between nucleic acids and amino acids in living organisms. Studying the structure of rRNA and how it functions in cells can help astrobiologists understand how these molecules became such a necessary a part of life’s cellular machinery.

The Georgia Tech team has released high-resolution, editable versions of their results online in the hope that other researchers can evaluate and add to the revisions they have made (http://apollo.chemistry.gatech.edu/RibosomeGallery).

The paper, “Secondary structure and domain architecture of the 23S and 5S rRNAs,” was published in the journal Nucleic Acids Research in June, 2013, and is available online at: http://nar.oxfordjournals.org/content/early/2013/06/14/nar.gkt513.full#xref-ref-43-1