Binding and release of eukaryotic initiation factor eIF-2 and GTP during protein synthesis initiation.

Proceedings of the National Academy of Sciences of the United States of America ·Vol. 75 ·No. 1 ·1978-01-00 ·Pages 204-8

Trachsel H, Staehelin T

Abstract

The eukaryotic initiation factor eIF-2 forms a ternary complex with Met-tRNAf and GTP. This complex binds to the 40S ribosomal subunit in the absence of mRNA and mRNA binding factors. Highly purified eIF-2 from rabbit reticulocytes was labeled with 125I by using the Bolton-Hunter reagent or with [gamma-32P]ATP by using the heme-regulated translational inhibitor protein kinase. The labeled eIF-2 was bound, together with equimolar amounts of Met-tRNAf and GTP, to the 40S subunit. In the presence of mRNA, mRNA binding factors, and 60S ribosomal subunits (complete initiation assay), eIF-2 was released from the 40S initiation complex in the subunit joining reaction. GTP also was released in this step and probably was hydrolyzed in the reaction that is dependent upon eIF-5 and the 60S subunit. The function of phosphorylated eIF-2 in initiation of protein synthesis is discussed.

MeSH Terms

Animals Guanosine Triphosphate/metabolism Peptide Chain Initiation, Translational Peptide Initiation Factors Phosphates/metabolism Protein Binding RNA, Transfer/metabolism Rabbits Ribosomes/metabolism

Chemicals

Peptide Initiation Factors Phosphates Guanosine Triphosphate RNA, Transfer

Authors & Affiliations

2 authors, click to expand affiliations / ORCID

Trachsel H

Staehelin T

References (21)

21 references, click to expand

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Article Info

Journal

Proceedings of the National Academy of Sciences of the United States of America

Abbr.

Proc Natl Acad Sci U S A

ISSN

0027-8424

DOI

10.1073/pnas.75.1.204

Published

1978-01-00

Pages

204-8

Language

English

Region

United States

NLM ID

7505876

PMCID

PMC411214

Subset

External Links

PubMed source DOI: 10.1073/pnas.75.1.204 PMC Full Text View journal details

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Binding and release of eukaryotic initiation factor eIF-2 and GTP during protein synthesis initiation.

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