Escherichia coli 5S RNA binding proteins L18 and L25 interact with 5.8S RNA but not with 5S RNA from yeast ribosomes.

Abstract

Reconstitution experiments showed that the 2 E. coli 5S RNA binding proteins L18 and L25 form a specific complex with yeast (Saccharomyces cerevisiae) 5.8S RNA and not with yeast 5S RNA. The yeast 5.8S RNA.sbd.E. coli protein complex was found to exhibit ATPase and GTPase activities that had previously been observed for the E. coli 5S RNA.sbd.protein complex. The tetranucleotide UpUpCpG, which is an analog of the tRNA fragment Tp.psi.pCpG, interacted strongly with 5S RNA-protein complexes from E. coli and Bacillus stearothermophilus and weakly with yeast 5.8S RNA. UpUpCpG did not bind to E. coli, B. stearothermophilus or yeast 5S RNA or to the yeast 5.8S RNA.sbd.E. coli protein complex. It is suggested that 5.8S RNA evolved from prokaryotic 5S RNA and that the latter 2 RNA are related and have similar functions in protein synthesis.