Abstract: Transfer RNAs (tRNAs) are essential adapter molecules of protein synthesis, mediating the translation of the genetic codes into amino acid sequences. To be fully active, tRNAs undergo an extensive range of post-transcriptional modifications that not only maintain the molecule’s structural stability but also ensure translational competency and promote cellular viability, especially in response to cellular stress factors. Due to the importance of tRNA modifications on the survival of bacteria, tRNA modification enzymes hold promise to be a novel antimicrobial drug target. Recently, we discovered a set of unstudied bacterial enzymes found in pathogenic organisms including Mycobacterium smegmatis, Mycobacterium tuberculosis, and Clostridium innocuum. Based on the gene context, these enzymes are hypothesized to be involved in tRNA modification pathways and hence could potentially be potent antibiotic targets against the aforementioned pathogens. First, the enzyme from M. smegmatis has been expressed in E. coli and purified. The absorbance spectra we obtained from UV-Vis spectroscopic analysis of the purified protein exhibits a leftward shift from 280 nm to 260 nm, indicating the presence of nucleic acids, supporting the hypothesis that this enzyme may modify tRNA. Attempts at extracting the nucleic acid copuritant for identification has been unsuccessful due to possible RNases contamination during the purification process. With more precautions employed, we hope to isolate the nucleic acids in near future to characterize the enzyme and its nucleic acid substrates of M. smegmatis and the other two bacterial strains.
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