Polypeptide chain initiation in eukaryotes: mechanism of formation of initiation complex.

Proceedings of the National Academy of Sciences of the United States of America ·Vol. 73 ·No. 2 ·1976-02-00 ·Pages 298-301

Nombela C, Nombela NA, Ochoa S, Safer B, Anderson WF, Merrick WC

Abstract

Artemia salina ribosomal subunits and highly purified reticulocyte initiation factors (IF) are used to study the mechanism of formation of the puromycin-sensitive initiation complex Met-tRNAi-80S ribosome-AUG. A complex with equimolar amounts of 40S subunit, GTP, and Met-tRNAi is formed at low Mg2+ concentration with a requirement for IF-MP (homogeneous) but not AUG or other factors. An 80S complex is formed only upon the further addition of AUG, IF-M2A, and IF-M2B, but not of either factor alone. This complex contains no GTP or GDP. A 40S complex, which cannot be converted to an 80S one, is formed when the nonhydrolyzable analog GMPPCP is substituted for GTP. IF-M2A has no effect on the formation of this complex, but IF-M2B enhances its formation.

MeSH Terms

Animals Crustacea/metabolism Guanosine Triphosphate/metabolism Peptide Chain Initiation, Translational Peptide Initiation Factors Puromycin/metabolism RNA, Transfer/metabolism Rabbits Reticulocytes/metabolism Ribosomes/metabolism Templates, Genetic

Chemicals

Peptide Initiation Factors Puromycin Guanosine Triphosphate RNA, Transfer

Authors & Affiliations

6 authors, click to expand affiliations / ORCID

Nombela C

Nombela N A

Ochoa S

Safer B

Anderson W F

Merrick W C

References (14)

14 references, click to expand

Initiation of eukaryotic protein synthesis: (Met-tRNA f -40S ribosome) initiation complex catalysed by purified initiation factors in the absence of mRNA.
Nat New Biol. 1973 Mar 14;242(115):35-8 PMID: 4512006
Two eukaryotic initiation factors (IF-I and IF-II) of protein synthesis that are required to form an initiation complex with rabbit reticulocyte ribosomes.
Proc Natl Acad Sci U S A. 1974 Feb;71(2):436-40 PMID: 4521815
Protein synthesis initiation in eukaryotes. Characterization of ribosomal factors from mouse fibroblasts.
J Biol Chem. 1973 Sep 25;248(18):6416-25 PMID: 4581104
Polypeptide chain initiation in eukaryotes: initiation factor requirements for translation of natural messengers.
Proc Natl Acad Sci U S A. 1976 Jan;73(1):44-8 PMID: 1061126
Purification and characterization of homogeneous initiation factor M2A from rabbit reticulocytes.
J Biol Chem. 1975 Jul 25;250(14):5556-62 PMID: 1095581
Polypeptide chain initiation in eukaryotes: initiation factor MP in Artemia salina embryos.
Proc Natl Acad Sci U S A. 1975 Oct;72(10):3947-51 PMID: 1105571
Nature of eukaryotic proteins required for joining of 40S and 60S ribosomal subunits.
Biochem Biophys Res Commun. 1975 Mar 17;63(2):409-16 PMID: 1125031
The ribosome cycle in mammalian protein synthesis. 3. Evidence that the nonribosomal proteins bound to the native smaller subunit are initiation factors.
J Biol Chem. 1973 Jun 25;248(12):4386-93 PMID: 4736429
Binding of radioactive oligonucleotides to ribosomes.
Biochemistry. 1971 Nov;10(23):4318-23 PMID: 4942456
A supernatant factor involved in initiation complex formation with eukaryotic ribosomes.
Proc Natl Acad Sci U S A. 1971 Dec;68(12):3059-63 PMID: 4943553
Nonribosomal proteins associated with eukaryotic native small ribosomal subunits.
Proc Natl Acad Sci U S A. 1975 Sep;72(9):3392-6 PMID: 1059126
Eukaryotic initiation complex formation. Evidence for two distinct pathways.
J Biol Chem. 1975 Dec 10;250(23):9083-9 PMID: 1194278
Protein synthesis in rabbit reticulocytes. A study of Met-tRNA f Met binding factor(s) and Met-tRNA f Met binding to ribosomes and AUG codon.
J Biol Chem. 1975 Feb 10;250(3):853-62 PMID: 1112794
A ribosome dissociation factor from rabbit reticulocytes distinct from initiation factor M3.
Proc Natl Acad Sci U S A. 1973 Aug;70(8):2220-3 PMID: 4525161

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.73.2.298

Published

1976-02-00

Pages

298-301

Language

English

Region

United States

NLM ID

7505876

PMCID

PMC335894

Subset

External Links

PubMed source DOI: 10.1073/pnas.73.2.298 PMC Full Text View journal details

Analysis Services

Polypeptide chain initiation in eukaryotes: mechanism of formation of initiation complex.

Contact

WeChat Official Account