Further in-silico Evidence for the Evolution of Transfer RNA from Ribozymes

Abstract

Since the transfer RNA (tRNA) of Archaea is believed to be the oldest nucleic acid and domain of microorganisms, respectively, on Earth, its dependency on protein endonuclease enzymes for processing is thought to be the result of coevolution of tRNA intron motifs with tRNA endonuclease architecture. Another school of thought, however, suggests that ribozymes, ancient RNA-only catalysts which perform many of the same functions as present-day protein enzymes, were responsible for the processing of archaeal tRNA, much in the same manner that they currently still do in bacterial tRNA. This hypothesis has recently gained even more support with the in-silico discovery of vestigial aminoacylating ribozyme nucleotide sequences in some of the oldest modern-day Archaea. To that end, an in-silico study was performed in an attempt to find evidence of vestigial magnesium-dependent hammerhead self-cleaving ribozyme sequence motifs in archaeal tRNA.