Functional role of the conserved amino acids Cysteine 81, Arginine 279, Glycine 280 and Arginine 283 in elongation factor Tu from Escherichia coli

Loading...
Thumbnail Image
Date
2011
Authors
Mo, Fan
Journal Title
Journal ISSN
Volume Title
Publisher
Lethbridge, Alta. : University of Lethbridge, Dept. of Chemistry and Biochemistry, c2011
Abstract
During protein synthesis, elongation factor Tu (EF-Tu) delivers aminoacyl-tRNA (aa-tRNA) to the A-site of mRNA-programmed ribosomes in a GTP-dependent manner. To enable future studies on the functional and structural requirement of EF-Tu’s function, a Cysteine-free variant of EF-Tu was constructed suitable for subsequent labelling of the protein and use in kinetic studies. Here, the kinetic properties of three Cysteine-less EF-Tu variants are reported, demonstrating that only the variant with the Alanine substitution in position 81 retains wild-type activity with respect to the interaction with guanine nucleotides, aa-tRNA and the ribosome. To explore a possible tRNA independent pathway for the GTPase activation signal, three residues in domain II of EF-Tu (Arginine 279, Glycine 280, Arginine 283) were mutated; the activity of EF-Tu variants were analyzed. Results suggest that these residues are indeed required for efficient ribosome-dependent stimulation of the GTPase activity of EF-Tu.
Description
x, 85 leaves : ill. (some col.) ; 29 cm
Keywords
Aminoacyl-tRNA , Guanosine triphosphatase , Proteins -- Synthesis , Binding sites (Biochemistry) , Genetic translation , Escherichia coli , Dissertations, Academic
Citation