Thermodynamic analysis reveals that GTP binding affects the interaction between the {alpha}- and {gamma}-subunits of translation initiation factor 2
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, University of Tokyo, 301 FBS-Building, 5-1-5 Kashiwanoha, Kashiwa 277-8562 (Japan)
- Faculty of Advanced Life Sciences, Hokkaido University, Sapporo 060-0810 (Japan)
Eukaryotic and archaeal translation initiation factors 2, heterotrimers that consist of {alpha}-, {beta}-, and {gamma}-subunits, deliver methionylated initiator tRNA to a small ribosomal subunit in a manner that depends on GTP. To evaluate correlation of the function and association of the subunits, we used isothermal titration calorimetry to analyze the thermodynamics of the interactions between the {alpha}- and {gamma}-subunits in the presence or absence of a nonhydrolyzable GTP analog or GDP. The {alpha}-subunits bound to the {gamma}-subunit with large heat capacity change ({delta}C{sub p}) values. The {delta}H and {delta}C{sub p} values for the interaction between the {alpha}- and {gamma}-subunits varied in the presence of the GTP analog but not in the presence of GDP. These results suggest that the binding of both the {alpha}-subunit and GTP changes the conformation of the switch region of the {gamma}-subunit and increases the affinity of the {gamma}-subunit for tRNA.
- OSTI ID:
- 21143746
- Journal Information:
- Biochemical and Biophysical Research Communications, Vol. 371, Issue 4; Other Information: DOI: 10.1016/j.bbrc.2008.03.101; PII: S0006-291X(08)00552-4; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0006-291X
- Country of Publication:
- United States
- Language:
- English
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