Under certain conditions, initiation factor 3 (IF-3) can cause the release of aminoacyl-tRNA bound to 30S ribosomal subunits of E. coli. It is shown that this IF-3-induced aminoacyl-tRNA release cannot be attributed to either nucleolytic attack or competition between IF-3 and aminoacyl-tRNA for the same ribosomal binding site. It was found that the 30S-aminoacyl-tRNA-codon complexes formed in the absence of IF-3 are intrinsically different from those prepared in the presence of IF-3. In the absence of IF-3, the ribosomal binding of aminoacyl-tRNA is a virtually irreversible process, since the bound aminoacyl-tRNA can neither be spontaneously released upon dilution nor exchanged for unbound aminoacyl-tRNA. In the presence of IF-3, the binding of one molecule of IF-3 per 30S ribosome renders the binding of aminoacyl-tRNA reversible upon dilution and promotes exchange between bound and unbound aminoacyl-tRNA. It is suggested that this difference is due to a conformational transition of the 30S ribosomal subunit induced by the binding of IF-3. The possible implications of this finding in relation to the mechanism of action of IF-3 and its functional role in the cell are discussed.
Requirement of initiation factor 3 in the initiation of polypeptide synthesis with N-acetylphenylalanyl-tRNA
Translation of the genetic message. VII. Role of initiation factors in formation of the chain initiation complex with Escherichia coli ribosomes
Function of three protein factors and ribosomal subunits in the initiation of protein synthesis in E. coli
Initiation of protein synthesis in Escherichia coli. II. Role of the initiation factors in polypeptide synthesis
Initiation factor dependent release of aminoacyl-tRNAs from complexes of 30S ribosomal subunits, synthetic polynucleotide and aminoacyl tRNA
Escherichia coli initiation factor IF3 binding to AUG and AUG-containing single strands and hairpin loops, and nonspecific binding to polymers
A proposed role for IF-3 and EF-T in maintaining the specificity of prokaryotic initiation complex formation
Identification of the ribosome binding sites of translation initiation factor IF3 by multidimensional heteronuclear NMR spectroscopy
Translation of mRNAs with degenerate initiation triplet AUU displays high initiation factor 2 dependence and is subject to initiation factor 3 repression
Selective stimulation of translation of leaderless mRNA by initiation factor 2: evolutionary implications for translation
The antibiotic Furvina® targets the P-site of 30S ribosomal subunits and inhibits translation initiation displaying start codon bias
A single mutation in the IF3 N-terminal domain perturbs the fidelity of translation initiation at three levels
Letter to the editor: Circular dichroism analysis of the ribosomal binding of initiation factor IF-3
Reactivity of ribosomal sulfhydryl groups in 30S ribosomal subunits of Escherichia coli and 30S-IF-3 complexes
Structure--function relationship in Escherichia coli initiation factors: role of tyrosine residues in ribosomal binding and functional activity of IF-3
Mechanism of translational initiation in prokaryotes. Evidence for a direct effect of IF2 on the activity of the 30 S ribosomal subunit
Initiation factor IF-3 and the binary complex between initiation factor IF-2 and formylmethionyl-tRNA are mutually exclusive on the 30-S ribosomal subunit
The mechanism of codon-anticodon interaction in ribosomes. Quantitative study of codon-dependent binding of tRNA to the 30-S ribosomal subunits of Escherichia coli
Specificity and properties of the destabilization, induced by initiation factor IF-3, of ternary complexes of the 30-S ribosomal subunit, aminoacyl-tRNA and polynucleotides
Regulation of the activity of chloroplast translational initiation factor 3 by NH2- and COOH-terminal extensions.
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