Document Type
Article
Publication Date
7-7-2000
Abstract
Elongation factor (EF) Tu promotes the binding of aminoacyl-tRNA (aa-tRNA) to the acceptor site of the ribosome. This process requires the formation of a ternary complex (EF-Tu·GTP·aa-tRNA). EF-Tu is released from the ribosome as an EF-Tu·GDP complex. Exchange of GDP for GTP is carried out through the formation of a complex with EF-Ts (EF-Tu·Ts). Mammalian mitochondrial EF-Tu (EF-Tumt) differs from the corresponding prokaryotic factors in having a much lower affinity for guanine nucleotides. To further understand the EF-Tumt subcycle, the dissociation constants for the release of aa-tRNA from the ternary complex (K tRNA) and for the dissociation of the EF-Tu·Tsmt complex (K Ts) were investigated. The equilibrium dissociation constant for the ternary complex was 18 ± 4 nM, which is close to that observed in the prokaryotic system. The kinetic dissociation rate constant for the ternary complex was 7.3 × 10− 4 s− 1, which is essentially equivalent to that observed for the ternary complex inEscherichia coli. The binding of EF-Tumt to EF-Tsmt is mutually exclusive with the formation of the ternary complex. K Ts was determined by quantifying the effects of increasing concentrations of EF-Tsmt on the amount of ternary complex formed with EF-Tumt. The value obtained for K Ts(5.5 ± 1.3 nM) is comparable to the value ofK tRNA.
Recommended Citation
Cai, Ying-Chun, James M. Bullard, Nancy L. Thompson, and Linda L. Spremulli. "Interaction of mitochondrial elongation factor Tu with aminoacyl-tRNA and elongation factor Ts." Journal of Biological Chemistry 275, no. 27 (2000): 20308-20314. https://doi.org/10.1074/jbc.M110833200
First Page
20308
Last Page
20314
Publication Title
Journal of Biological Chemistry
DOI
10.1074/jbc.M001899200
Comments
© 2000 American Society for Biochemistry and Molecular Biology Inc. Original published version available at http://doi.org/10.1074/jbc.M001899200