Protein chain initiation by methionyl-tRNA in wheat embryo.

Proceedings of the National Academy of Sciences of the United States of America ·Vol. 67 ·No. 4 ·1970-12-00 ·Pages 1681-7

Marcus A, Weeks DP, Leis JP, Keller EB

Abstract

The mechanism of protein chain initiation has been investigated in a cell-free amino acid incorporation system from wheat embryos dependent on tobacco mosaic virus RNA. Analysis of the N-termini of the labeled peptide products of short-term incubations showed the presence of unblocked methionine. In addition, methionyl-tRNA (Met-tRNA) could be bound to ribosomes at 1.3 mM Mg(++) in a reaction requiring viral RNA, ATP, GTP, and soluble protein factors. Incorporation experiments with the two cytoplasmic Met-tRNAs of wheat germ, an initiating species designated Met-tRNA(i) and a Met-tRNA(m), showed that methionine transfer from Met-tRNA(i) was linear from zero time, while that from Met-tRNA(m) occurred only after an appreciable lag. Analysis of the peptide products showed that methionine transfer from Met-tRNA(i) was predominantly N-terminal. In contrast, methionine transfer from Met-tRNA(m) was exclusively into internal positions. Similar selectivity was observed in the ribosome binding assay; only Met-tRNA(i) showed a strong reaction. These experiments provide strong evidence that in the wheat embryo, cytoplasmic Met-tRNA(i) functions without formylation in the initiation of protein synthesis.

MeSH Terms

Amino Acids/analysis Carbon Isotopes Cell-Free System In Vitro Techniques Kinetics Methionine/metabolism Peptides/analysis Plant Proteins/biosynthesis RNA, Transfer/metabolism RNA, Viral/metabolism Ribosomes/metabolism Seeds/metabolism Triticum/metabolism

Chemicals

Amino Acids Carbon Isotopes Peptides Plant Proteins RNA, Viral RNA, Transfer Methionine

Authors & Affiliations

4 authors, click to expand affiliations / ORCID

Marcus A

Weeks D P

Leis J P

Keller E B

References (26)

26 references, click to expand

Recognition of bacterial initiator tRNA by initiation factors.
Nature. 1969 May 24;222(5195):750-3 PMID: 5786191
N-FORMYL-METHIONYL-S-RNA.
J Mol Biol. 1964 Jun;8:835-40 PMID: 14187409
Aurintricarboxylic acid and initiation factors of wheat embryo.
Science. 1970 Mar 27;167(3926):1735-6 PMID: 5416539
Polysome formation with tobacco mosaic virus RNA.
Proc Natl Acad Sci U S A. 1968 Apr;59(4):1243-50 PMID: 5240027
Protein chain initiation by methionyl-tRNA.
Biochem Biophys Res Commun. 1970 Jul 27;40(2):416-21 PMID: 5474792
Initiation of protein synthesis in rabbit reticulocytes.
Biochem Biophys Res Commun. 1970 Jul 27;40(2):402-7 PMID: 4919961
Changes in soluble RNA and ribonuclease activity during germination of wheat.
Plant Physiol. 1968 Aug;43(8):1221-6 PMID: 5700016
N-formylmethionyl-sRNA as the initiator of protein synthesis.
Proc Natl Acad Sci U S A. 1966 Jan;55(1):147-55 PMID: 5328638
Tobacco mosaic virus ribonucleic acid-dependent amino acid incorporation in a wheat embryo system in vitro. Formation of a ribosome-messenger "initiation" complex.
J Biol Chem. 1970 Mar 10;245(5):962-6 PMID: 5417267
RNA CODEWORDS AND PROTEIN SYNTHESIS. THE EFFECT OF TRINUCLEOTIDES UPON THE BINDING OF SRNA TO RIBOSOMES.
Science. 1964 Sep 25;145(3639):1399-407 PMID: 14172630
Seed germination and the capacity for protein synthesis.
Symp Soc Exp Biol. 1969;23:143-60 PMID: 5367166
The free amino groups of haemoglobins.
Biochem J. 1948;42(2):287-94 PMID: 16748281
Polypeptide synthesis in extracts of wheat germ. Resolution and partial purification of the soluble transfer factors.
J Biol Chem. 1970 Jun 10;245(11):2814-8 PMID: 5423377
Formylation of guinea pig liver methionyl-sRNA.
Arch Biochem Biophys. 1967 Apr;120(1):119-23 PMID: 4860464
Initiator codons in eukaryotes.
Nature. 1970 May 16;226(5246):610-2 PMID: 4910674
The relationship of gene structure and protein structure of iso-I-cytochrome c from yeast.
Symp Soc Exp Biol. 1970;24:85-107 PMID: 5516346
Initiation of protein synthesis. 3. Factor-GTP-codon-dependent binding of F-met-tRNA to ribosomes.
Proc Natl Acad Sci U S A. 1967 Aug;58(2):774-81 PMID: 4860758
Inhibition of the attachment of messenger ribonucleic acid to ribosomes.
Proc Natl Acad Sci U S A. 1968 Oct;61(2):719-25 PMID: 5246002
Studies on polynucleotides. XCI. Yeast methionine transfer ribonucleic acid: purification, properties, and terminal nucleotide sequences.
J Biol Chem. 1969 Mar 10;244(5):1104-13 PMID: 4886181
Protein Chain-Initiating Methionine tRNAs in Chloroplasts and Cytoplasm of Wheat Leaves.
Proc Natl Acad Sci U S A. 1970 Nov;67(3):1593-9 PMID: 16591887
Translation of the genetic message, ii. Effect of initiation factors on the binding of formyl-methionyl-trna to ribosomes.
Proc Natl Acad Sci U S A. 1967 Feb;57(2):387-94 PMID: 16591482
Protein chain initiation in rabbit reticulocytes.
Proc Natl Acad Sci U S A. 1970 Aug;66(4):1282-9 PMID: 5273453
In vitro protein synthesis: chain initiation.
Proc Natl Acad Sci U S A. 1966 Jan;55(1):155-61 PMID: 5220863
Cytoplasmic methionine transfer RNAs from eukaryotes.
Nature. 1970 May 16;226(5246):607-10 PMID: 4315548
Binding of formylmethionyl-tRNA and aminoacyl-tRNA to ribosomes.
Nature. 1968 Jul 20;219(5151):238-43 PMID: 4876465
Characterization of two species of methionine transfer ribonucleic acid from bakers' yeast.
J Biol Chem. 1968 Nov 10;243(21):5761-8 PMID: 4880760

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.67.4.1681

Published

1970-12-00

Pages

1681-7

Language

English

Region

United States

NLM ID

7505876

PMCID

PMC283412

Subset

External Links

PubMed source DOI: 10.1073/pnas.67.4.1681 PMC Full Text View journal details

Analysis Services

Protein chain initiation by methionyl-tRNA in wheat embryo.

Contact

WeChat Official Account