Escherichia coli 30S mutants lacking protein S20 are defective in translation initiation.
The 30S ribosomal subunits derived from Escherichia coli TA114, a a temperature-sensitive mutant lacking ribosomal protein S20, were shown to be defective in two ways: (a) they have a reduced capacity for association with the 50S ribosomal subunit which results in the impairment of most of the functions requiring a coordinated interaction between the two subunits; (b) they are defective in functions which do not require their interaction with the large subunit (i.e., the formation of ternary complexes with aminocyl-tRNAs and templates, including the formation of 30S initiation complexes with fMet-tRNA and mRNA). The 30S (-S20) subunits seem to interact normally with both template and aminoacyl-tRNA individually, but appear to be impaired in the rate-limiting isomerization step leading to the formation of a codon-anticodon interaction in the P site.
Götz
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Max-Planck-Institut für Molekulare Genetik, Berlin, Germany.
Dabbs
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Gualerzi
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D007700:Kinetics; D009154:Mutation; D010452:Peptide Biosynthesis; D010442:Peptide Chain Initiation, Translational; D010455:Peptides; D011072:Poly U; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000235:genetics*; D012270:Ribosomes / Q000378:metabolism*; D013696:Temperature
D010455:Peptides; D012346:RNA, Transfer, Amino Acyl; D012269:Ribosomal Proteins; C029611:ribosomal protein S20; C006383:tRNA, N-acetylphenylalanine-; D011072:Poly U; C012001:polyphenylalanine