TY - JOUR
T1 - Specific interaction of eukaryocytic translation initiation factor 5 (eIF5) with the β-subunit of eIF2
AU - Das, Supratik
AU - Maiti, Tapan
AU - Das, Kallol
AU - Maitra, Umadas
PY - 1997/12/12
Y1 - 1997/12/12
N2 - Eukaryotic translocation initiation factor 5 (eIF5) interacts with the 40 S initiation complex (40 S · mRNA · eIF3 · Met-tRNA(f) · eIF2 · GTP) and mediates hydrolysis of the bound GTP. To characterize the molecular interactions involved in eIF5 function, we have used 32P-labeled recombinant rat eIF5 as a probe in filter overlay assay to identify eIF5- interacting proteins in crude initiation factor preparations. We observed that eIF5 specifically interacted with the β subunit of initiation factor eIF2. No other initiation factors including the γ subunit of eIF2 tested positive in this assay. Furthermore, both yeast and mammalian or yeast eIF2. Binding analysis with human eIF2β deletion mutants expressed in Escherichia coli identified a 22-amino acid domain, between amino acids 68 and 89, as the primary eIF5-binding region of eIF2β. These results along with our earlier observations that (a) eIF5 neither binds nor hydrolyzes free GTP or GTP bounds as Met-tRNA(f) · eIF2 · GTP ternary complex, and (b) eIF5 forms a specific complex with eIF2 suggests that the specific interaction between eIF5 and the β subunit of eIF2 may be critical for the hydrolysis of GTP during translation initiation.
AB - Eukaryotic translocation initiation factor 5 (eIF5) interacts with the 40 S initiation complex (40 S · mRNA · eIF3 · Met-tRNA(f) · eIF2 · GTP) and mediates hydrolysis of the bound GTP. To characterize the molecular interactions involved in eIF5 function, we have used 32P-labeled recombinant rat eIF5 as a probe in filter overlay assay to identify eIF5- interacting proteins in crude initiation factor preparations. We observed that eIF5 specifically interacted with the β subunit of initiation factor eIF2. No other initiation factors including the γ subunit of eIF2 tested positive in this assay. Furthermore, both yeast and mammalian or yeast eIF2. Binding analysis with human eIF2β deletion mutants expressed in Escherichia coli identified a 22-amino acid domain, between amino acids 68 and 89, as the primary eIF5-binding region of eIF2β. These results along with our earlier observations that (a) eIF5 neither binds nor hydrolyzes free GTP or GTP bounds as Met-tRNA(f) · eIF2 · GTP ternary complex, and (b) eIF5 forms a specific complex with eIF2 suggests that the specific interaction between eIF5 and the β subunit of eIF2 may be critical for the hydrolysis of GTP during translation initiation.
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U2 - 10.1074/jbc.272.50.31712
DO - 10.1074/jbc.272.50.31712
M3 - Article
C2 - 9395514
AN - SCOPUS:0031282976
VL - 272
SP - 31712
EP - 31718
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 50
ER -