Cell 135, 462–474 (2008) doi:10.1016/j.cell.2008.09.013

One of two processes thought to be catalysed by RNA and common to all life forms does not actually need its RNA.

The RNase P catalyst, normally made of RNA and protein, chops superfluous subunits off immature versions of tRNA molecules, which are essential for protein synthesis. A quarter of a century ago, this catalyst's RNA component was shown to be crucial to its function in bacterial cells; since then, researchers have shown that this RNA can do the job without any help from proteins in the two other evolutionary branches of life, archaea and eukaryotes.

But Walter Rossmanith of the Medical University of Vienna and his colleagues have identified and purified the components of human mitochondrial RNase P, finding only proteins, and reconstituted its catalytic activity using just three of these.