TY - JOUR
T1 - Distinct epitopes in eukaryotic initiation factor 2 for binding of mRNA and for ternary complex formation with methionyl-tRNAf and GTP
AU - Harary, Ronit
AU - Kaempfer, Raymond
PY - 1990/8/27
Y1 - 1990/8/27
N2 - Eukaryotic initiation factor 2 (eIF-2) forms a ternary complex with methionyl-tRNAMetf and GTP on one hand, and it binds to a specific site in mRNA molecules on the other. Antibodies directed against eIF-2 were used to analyze these dual binding activities. A monoclonal antibody directed against the β-subunit of eIF-2, 5A4, is able to inhibit ternary complex formation as well as binding of mRNA, showing that this subunit is essential for both binding activities of eIF-2. However, a polyclonal antibody, PR1, is able to distinguish between these activities in the eIF-2 molecule. In the presence of PR1, binding of mRNA by eIF-2 is inhibited completely, yet ternary complex formation with methionyl-tRNAMetf and GTP is stimulated more than 5-fold. Apparently, specific antibodies to eIF-2 can induce a conformational change in inactive factor molecules that permits them to form ternary complexes. These results show that distinct epitopes in eIF-2 are involved in binding of mRNA and in ternary complex formation with methionyl-tRNAMetf and GTP.
AB - Eukaryotic initiation factor 2 (eIF-2) forms a ternary complex with methionyl-tRNAMetf and GTP on one hand, and it binds to a specific site in mRNA molecules on the other. Antibodies directed against eIF-2 were used to analyze these dual binding activities. A monoclonal antibody directed against the β-subunit of eIF-2, 5A4, is able to inhibit ternary complex formation as well as binding of mRNA, showing that this subunit is essential for both binding activities of eIF-2. However, a polyclonal antibody, PR1, is able to distinguish between these activities in the eIF-2 molecule. In the presence of PR1, binding of mRNA by eIF-2 is inhibited completely, yet ternary complex formation with methionyl-tRNAMetf and GTP is stimulated more than 5-fold. Apparently, specific antibodies to eIF-2 can induce a conformational change in inactive factor molecules that permits them to form ternary complexes. These results show that distinct epitopes in eIF-2 are involved in binding of mRNA and in ternary complex formation with methionyl-tRNAMetf and GTP.
KW - Antibodies against eIF-2
KW - Eukaryotic initiation factor 2
KW - Translational control
KW - eIF-2 epitope
KW - mRNA binding
KW - methionyl-tRNA binding
UR - http://www.scopus.com/inward/record.url?scp=0025041056&partnerID=8YFLogxK
U2 - 10.1016/0167-4781(90)90153-S
DO - 10.1016/0167-4781(90)90153-S
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C2 - 1698457
AN - SCOPUS:0025041056
SN - 0167-4781
VL - 1050
SP - 129
EP - 133
JO - Biochimica et Biophysica Acta - Gene Structure and Expression
JF - Biochimica et Biophysica Acta - Gene Structure and Expression
IS - 1-3
ER -