Domain-dependent interaction of eukaryotic initiation factor eIF4A for binding to middle and C-terminal domains of eIF4G.
The interactions of recombinant human eIF4A (4A) and its N- and C-terminal side domains (AN and AC, respectively) with the middle- and C-terminal-domain-linked fragment (GMC) of eIF4G and its middle and C-terminal domains (GM and GC, respectively) were investigated by surface plasmon resonance (SPR) analysis and isothermal titration calorimetry (ITC). It is remarkable that the kinetic parameter-dependent SPR profile observed for the 4A-GMC pair was quite different from the steady affinity profiles of the 4A-GM/GC pairs, suggesting the simultaneous contribution of the middle and C-terminal domains of eIF4G for the binding with eIF4A. On the other hand, ITC yielded the enthalpy energies of -1.5 x 10(4) to -2.5 x 10(4) J/mol for the domain-domain interactions of 4A with GMC. Although the ITC profile of the 4A-GM pair reflects well the structural feature shown previously by NMR and X-ray analyses, it was essentially different from that of the 4A-GMC pair. The present results suggest that the intimate interaction between the eIF4A N- and C-terminal domains and the eIF4G middle and C-terminal domains is necessary to reveal the biologically active function of the eIF4A-eIF4G complex.
Fujita
Yuki
Y
Department of Physical Chemistry, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
Oe
Masako
M
Tutsumino
Tatsuya
T
Morino
Shigenobu
S
Imataka
Hiroaki
H
Tomoo
Koji
K
Ishida
Toshimasa
T
D002151:Calorimetry; D039601:Eukaryotic Initiation Factor-4A / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D039603:Eukaryotic Initiation Factor-4G / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D020349:Surface Plasmon Resonance; D013816:Thermodynamics; D017186:Titrimetry; D044366:Transition Temperature
C113920:EIF4G1 protein, human; D039603:Eukaryotic Initiation Factor-4G; D050505:Mutant Proteins; D011993:Recombinant Fusion Proteins; D039601:Eukaryotic Initiation Factor-4A