Functional Substitution of an Indirect Pathway for tRNA Glutaminylation with a Direct Pathway by T. thermophiles GlnRS

Abstract

In protein synthesis mechanism, there is aminoacyl-tRNA synthetase (AaRSs) enzyme which is essential for housekeeping enzymes and could be formed a ternary complex with any substrate known. In general, eukaryotic provides 20 sets of AaRS enzymes, while the other 18 sets are in prokaryotic. The differences of this phenomena, unfortunately because there are some of AaRSs syntheses by an indirect pathway using other AaRSs which has a high similarity of amino acid formula. Aminoacylation of transfer RNAGln (tRNAGln) is one of AaRSs carried out by an indirect pathway in most of organism, and even there are following distinctions in various kingdoms and also the mechanism in various kingdoms. ScGlnRS cytoplasm produced by the direct pathway of glutaminylation tRNAGln, besides mitochondrial Gln-tRNAGln generated a slightly complicated than the cytoplasm, because it must go through the step of amido attachment needed extra enzyme non-discriminating glutamyl-tRNA synthetase by specifically changing Glu-tRNAGln to Gln-tRNAGln. Genetic engineering has been done by combining enzymes from EcGlnRS bacteria with non-specific binding tRNA cofactors from yeast, known as Arc1p, capable of increasing tRNA binding and activity of enzyme from bacteria to yeast system in vivo both in cytoplasm and mitochondria. By using the same combination of Arc1p to TtGlnRS bacterial enzyme, different mechanisms were found because they were only able to function in the mitochondria as well, not with the cytoplasm. T. thermophilus posses similarity in tRNA identity determinants of E. Coli but has a difference in yeast cytoplasm and mitochondrial tRNAGln isoacceptors. Arc1p-TtGlnRS fusion significantly enhanced its protein expression. In this finding, we report the trans-kingdom and eukaryotic glutaminylation were able to replace the role of the enzyme from yeast, it can also express equally noteworthy.