Investigating the glutamine-trna (glutamine) synthesis appartus of the human pathogen helicobacter pylori
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چکیده
INVESTIGATING THE GLUTAMINE-TRNA (GLUTAMINE) SYNTHESIS APPARTUSOF THE HUMAN PATHOGEN HELICOBACTER PYLORIby NILESH JOSHIAugust 2012Advisor: Tamara L. HendricksonMajor: ChemistryDegree: Master of ScienceAccurate protein biosynthesis is a vital process to all cellular life. Aminoacyl-tRNAs are at the heart of this process: A correctly formed aminoacyl-tRNA is critical forprotein biosynthesis. Organisms have evolved many mechanisms to repair misacylatedtRNAs before they cause errors in protein biosynthesis, thus maintaining the integrity ofthe genetic code. The human pathogen Helicobacter pylori (H. pylori) synthesizes Glu-tRNA as an intermediate to producing Gln-tRNA. This misacylated intermediatecould cause lethal errors if used by the ribosome for protein synthesis. H. pylori repairsthis intermediate by the amidotransferase GatCAB.This dissertation focuses on indirect aminoacylation and transamidation toproduce Gln-tRNA in H. pylori. A combination of phylogenetic analyses andenzymatic assays were used that contribute to a picture of this process.Chapter 2 discusses our examination of sequence conservation of gltX2 (the genethat encodes GluRS2) across different H. pylori strains. The conclusions of thissequencing effort are compared with trends in sequences of genes important in theaminoacylation step of protein synthesis.
منابع مشابه
Gln-tRNAGln synthesis in a dynamic transamidosome from Helicobacter pylori, where GluRS2 hydrolyzes excess Glu-tRNAGln
In many bacteria and archaea, an ancestral pathway is used where asparagine and glutamine are formed from their acidic precursors while covalently linked to tRNA(Asn) and tRNA(Gln), respectively. Stable complexes formed by the enzymes of these indirect tRNA aminoacylation pathways are found in several thermophilic organisms, and are called transamidosomes. We describe here a transamidosome form...
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