scholarly journals Kinetics of the Interactions between Yeast Elongation Factors 1A and 1Bα, Guanine Nucleotides, and Aminoacyl-tRNA

2007 ◽  
Vol 282 (49) ◽  
pp. 35629-35637 ◽  
Author(s):  
Kirill B. Gromadski ◽  
Tobias Schümmer ◽  
Anne Strømgaard ◽  
Charlotte R. Knudsen ◽  
Terri Goss Kinzy ◽  
...  
Keyword(s):  
Elongation Factor ◽  
Guanine Nucleotides ◽  
Stopped Flow ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Binding Properties ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factor ◽  
Kinetics Of ◽  
Trna Binding

The interactions of elongation factor 1A (eEF1A) from Saccharomyces cerevisiae with elongation factor 1Bα (eEF1Bα), guanine nucleotides, and aminoacyl-tRNA were studied kinetically by fluorescence stopped-flow. eEF1A has similar affinities for GDP and GTP, 0.4 and 1.1 μm, respectively. Dissociation of nucleotides from eEF1A in the absence of the guanine nucleotide exchange factor is slow (about 0.1 s–1) and is accelerated by eEF1Bα by 320-fold and 250-fold for GDP and GTP, respectively. The rate constant of eEF1Bα binding to eEF1A (107–108m–1 s–1) is independent of guanine nucleotides. At the concentrations of nucleotides and factors prevailing in the cell, the overall exchange rate is expected to be in the range of 6 s–1, which is compatible with the rate of protein synthesis in the cell. eEF1A·GTP binds Phe-tRNAPhe with a Kd of 3 nm, whereas eEF1A·GDP shows no significant binding, indicating that eEF1A has similar tRNA binding properties as its prokaryotic homolog, EF-Tu.

Multiple Phosphorylation Sites and Quaternary Organization of Guanine-Nucleotide Exchange Complex of Elongation Factor-1 (EF-1βγδ/ValRS) Control the Various Functions of EF-1α

1998 ◽  
Vol 18 (3) ◽  
pp. 119-127 ◽  
Author(s):  
Odile Minella ◽  
Odile Mulner-Lorillon ◽  
Guillaume Bec ◽  
Patrick Cormier ◽  
Robert Bellé
Keyword(s):  
Structural Model ◽  
Elongation Factor ◽  
Trna Synthetase ◽  
Macromolecular Complex ◽  
Phosphorylation Sites ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Cellular Functions ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factor

The eukaryotic guanine-nucleotide exchange factor commonly called elongation factor-1βγδ (EF-1βγδ), comprises four different subunits including valyl-tRNA synthetase (EF-1βγδ/ValRS). The factor is multiply-phosphorylated by three different protein kinases, protein kinase C, casein kinase II and cyclin dependent kinase 1 (CDK1). EF-1βγδ/ValRS is organized as a macromolecular complex for which we propose a new structural model. Evidence that EF-1βγδ/ValRS is a sophisticated supramolecular complex containing many phosphorylation sites, makes it a potential regulator of any of the functions of its partner EF-1α, not only involved in protein synthesis elongation, but also in many other cellular functions.

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