Maintaining fidelity of protein biosynthesis: the role of pretransfer editing

Sumić, Sara (2009) Maintaining fidelity of protein biosynthesis: the role of pretransfer editing. Bachelor's thesis, Faculty of Science > Department of Biology.

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Abstract

Maintaining fidelity of protein biosynthesis is an essential feature of a cell. The first step of translation is synthesis of cognate amino acid:tRNA pairs by aminoacyl-tRNA synthetases (aaRS). These enzymes have to recognize and covalently link corresponding amino acid to its cognate tRNA. Selection of cognate amino acid represents a problem for some of aaRS, so they can misactivate near-cognate amino acids that are chemically and structurally similar to the cognate ones. In some cases, misactivated amino acid can be attached to tRNA. To maintain satisfying degree of translational quality, some aaRS have developed additional hydrolytic editing mechanisms to correct errors in the selection of amino acids. Editing can occur either before (pretransfer editing) or after aminoacylation to tRNA (posttransfer editing). In pretransfer editing, noncognate aminoacyl-adenylate is hydrolyzed, while in the posttransfer editing, misacylated tRNA is hydrolyzed. Many aaRS have separated and structurally distinct editing domain, where hydrolysis of misacylated tRNA takes place. With latest findings in this field of research, proposed mechanism for tRNA-dependent pretransfer editing becomes questionable. Some of the main issues are: where does aminoacyl-adenylate hydrolysis take place, within editing domain as misacylated tRNA, or within synthetic active site? What is the exact role for tRNA in that process? Both of the editing processes yield same final products, and both are tRNA dependent, so researches have difficulties with investigating them independently of one another. Still, mechanistic enzymology methods are used to further investigate pretransfer editing mechanism, and consequently to determine its role in maintaining fidelity of protein biosynthesis.

Item Type: Thesis (Bachelor's thesis)
Supervisor: Gruić Sovulj, Ita
Date: 2009
Number of Pages: 9
Subjects: NATURAL SCIENCES > Biology
Divisions: Faculty of Science > Department of Biology
Depositing User: Silvana Šehić
Date Deposited: 18 Dec 2014 11:01
Last Modified: 16 Feb 2016 13:58
URI: http://digre.pmf.unizg.hr/id/eprint/3544

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