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. 1976 Sep;73(9):3005–3009. doi: 10.1073/pnas.73.9.3005

Purification and characterization of initiation factor IF-E3 from rabbit reticulocytes.

R Benne, J W Hershey
PMCID: PMC430909  PMID: 1067598

Abstract

Initiation factor IF-E3 from rabbit reticulocytes was isolated from a high salf extract of ribosomes prepared according to the procedure of Schreier and Staehelin (J. Mol9 Biol, 73, 329-349, 1973). The factor was highly purified from the crude extract by ammonium sulfate fractionation, sucrose gradient centrifugation, salf gradient elution from DEAE-cellulose and phosphocellulose columns, and glycerol gradient centrifugation. IF-E3 stimulated cell-free protein synthesis dependent on an exogenous globin mRNA fraction 4- to 5-fold. The factor under nondenaturing conditions behaved as a large multipolypeptide complex, but was separated into 11 major protein components by two-dimensional polyacrylamide gel electrophoresis with urea and sodium dodecyl sulfate. The stoichiometry and molecular weights (range: 28,000-140,000) of the IF-E3 proteins were determined. None of the components corresponded to ribosomal proteins found in high salt-washed ribosomes. 14CH3-IF-E3 was prepared by reductive alkylation without detectable loss of its initiation factor activity, and bound stoichiometrically to 40S ribosomal subunits, but not to 60S or 80S ribosomes. 14CH3-IF-E3 isolated from the 40S complex contained only nine of the 11 original protein components.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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