TY - JOUR
T1 - Thermodynamic analysis reveals that GTP binding affects the interaction between the α- and γ-subunits of translation initiation factor 2
AU - Nakakido, Makoto
AU - Tanaka, Yoshikazu
AU - Sokabe, Masaaki
AU - Tsumoto, Kouhei
N1 - Funding Information:
We thank I. Tanaka and N. Sakai of Hokkaido University for their helpful suggestions.This work was supported in part by the National Project on Protein Structural and Functional Analyses (Ministry of Education, Culture, Sports, Science, and Technology of Japan). It was also supported in part by Grants-in-Aid for General Research (K.T.) and Younger Scientists (Y.T.) from the Ministry of Education, Science, Sports, and Culture of Japan.
PY - 2008/7/11
Y1 - 2008/7/11
N2 - Eukaryotic and archaeal translation initiation factors 2, heterotrimers that consist of α-, β-, and γ-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 α- and γ-subunits in the presence or absence of a nonhydrolyzable GTP analog or GDP. The α-subunits bound to the γ-subunit with large heat capacity change (ΔCp) values. The ΔH and ΔCp values for the interaction between the α- and γ-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 α-subunit and GTP changes the conformation of the switch region of the γ-subunit and increases the affinity of the γ-subunit for tRNA.
AB - Eukaryotic and archaeal translation initiation factors 2, heterotrimers that consist of α-, β-, and γ-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 α- and γ-subunits in the presence or absence of a nonhydrolyzable GTP analog or GDP. The α-subunits bound to the γ-subunit with large heat capacity change (ΔCp) values. The ΔH and ΔCp values for the interaction between the α- and γ-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 α-subunit and GTP changes the conformation of the switch region of the γ-subunit and increases the affinity of the γ-subunit for tRNA.
KW - GTP
KW - Thermodynamics
KW - Translation initiation factor 2
KW - tRNA binding
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U2 - 10.1016/j.bbrc.2008.03.101
DO - 10.1016/j.bbrc.2008.03.101
M3 - Article
C2 - 18381064
AN - SCOPUS:44149113261
VL - 371
SP - 596
EP - 599
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 4
ER -