Molecular evidence for the evolution of the eukaryotic mitochondrial arginyl‐tRNA synthetase from the prokaryotic suborder Cystobacterineae

Abstract

The evolutionary origin of the family of eukaryotic aminoacyl‐tRNA synthetases that are essential to all living organisms is a matter of debate. In order to shed molecular light on the ancient source of arginyl‐tRNA synthetase, a total of 1347 eukaryotic arginyl‐tRNA synthetase sequences were mined from databases and analyzed. Their multiple sequence alignment reveals a signature sequence that is characteristic of the nuclear‐encoded enzyme, which is imported into mitochondria. Using this molecular beacon, the origins of this gene can be traced to modern prokaryotes. In this way, a previous phylogenetic analysis linking Myxococcus to the emergence of the eukaryotic mitochondrial arginyl‐tRNA synthetase is supported by the unique existence of the molecular signature within the suborder Cystobacterineae that includes Myxococcus.