ASSEMBLY AND FUNCTION OF MACROMOLECULAR COMPLEXES FORACCURATE TRNA AMINOACYLATION IN HELICOBACTER PYLORIbyGAYATHRI SILVAMay 2014Advisor: Dr. Tamara L. HendricksonMajor: Chemistry (Biochemistry)Degree: Doctor of PhilosophyThe aminoacylation of tRNA is a critical step in maintaining the accuracyof the genetic code. Many microorganisms are missing one or mor...

The discovery of separate 5' and 3' halves of transfer RNA (tRNA) molecules-so-called split tRNA-in the archaeal parasite Nanoarchaeum equitans made us wonder whether ancestral tRNA was encoded on 1 or 2 genes. We performed a comprehensive phylogenetic analysis of tRNAs in 45 archaeal species to explore the relationship between the three types of tRNAs (nonintronic, intronic and split). We clas...

For most aminoacyl-tRNA synthetases (aaRS), their cognate tRNA is not obligatory to catalyze amino acid activation, with the exception of four class I (aaRS): arginyl-tRNA synthetase, glutamyl-tRNA synthetase, glutaminyl-tRNA synthetase and class I lysyl-tRNA synthetase. Furthermore, for arginyl-, glutamyl- and glutaminyl-tRNA synthetase, the integrated 3' end of the tRNA is necessary to activa...

INTRODUCTION................................................ 71 ORGANIZATION OF tRNA GENE REGIONS ................................................ o 71 Mapping of tRNA and rRNA Gene Clusters ................................................ 71 Large Clusters of tRNA genes-Evolutionary Considerations ................................................ 73 SEQUENCE ANALYSIS OF tRNA STRUCTURAL GENES .....

The tRNA structure contains conserved modifications that are responsible for its stability and are involved in the initiation and accuracy of the translation process. tRNA modification enzymes are prevalent in bacteria, archaea, and eukaryotes. tRNA Gm18 methyltransferase (TrmH) and tRNA m(1)G37 methyltransferase (TrmD) are prevalent and essential enzymes in bacterial populations. TrmH involves...

All mitochondrial tRNAs in Leishmania tarentolae are encoded in the nuclear genome and imported into the mitochondrion from the cytosol. One imported tRNA (tRNA(Trp)) is edited by a C to U modification at the first position of the anticodon. To determine the in vivo substrates for mitochondrial tRNA importation as well as tRNA editing, we examined the subcellular localization and extent of 5'- ...

Aminoacyl-tRNA synthetases catalyze the attachment of amino acids to their cognate tRNAs. In general, aminoacyl-tRNA synthetase assays require stoichiometric amounts of tRNA, which limits their sensitivity while increasing their cost. This requirement for stoichiometric amounts of tRNA can be alleviated if the aminoacyl-tRNA product is cleaved following the tRNA aminoacylation reaction, regener...

Human immunodeficiency virus type 1 (HIV-1) uses tRNA 3 Lys as a primer for reverse transcription and, during viral assembly, this tRNA is selectively packaged into the virus along with the other major tRNA Lys , tRNA 1,2 Lys. Increasing the cytoplasmic concentration of tRNA 3 Lys through transfection of cells with a plasmid containing both HIV-1 proviral DNA and a tRNA 3 Lys gene results in a ...

Transfer RNAs play a crucial role in protein translation where they bring amino acids to the ribosome be incorporated into nascent polypeptide chains. During stress conditions tRNAs can cleaved generate tRNA-derived fragments. Several ribonucleases have been identified that cleave tRNA, however mutations stress-induced ribonuclease Angiogenin range of neurological disorders including Amyotrophi...

Studies on translation frequently require large amounts of purified individual tRNAs. However, few purified tRNAs are commercially available. Individual tRNAs can be easily produced by in vitro transcription, but the lack of modifications of the tRNA transcripts may influence or impair their function [1,2]. The purification of specific tRNAs from total tRNA is a laborious process that requires ...