Abstract
Translation of SecM stalls unless its N-terminal part is "pulled" by the protein export machinery. Here we show that the sequence motif FXXXXWIXXXXGIRAGP that includes a specific arrest point (Pro) causes elongation arrest within the ribosome. Mutations that bypass the elongation arrest were isolated in 23S rRNA and L22 r protein. Such suppressor mutations occurred at a few specific residues of these components, which all face the narrowest constriction of the ribosomal exit tunnel. Thus, we suggest that this region of the exit tunnel interacts with nascent translation products and functions as a discriminating gate.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Motifs
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Amino Acid Sequence
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism*
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Carrier Proteins / genetics
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Carrier Proteins / metabolism*
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Cetrimonium
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Cetrimonium Compounds / pharmacology
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Detergents / pharmacology
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Models, Molecular
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Molecular Sequence Data
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Mutation
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Protein Biosynthesis / drug effects
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Protein Biosynthesis / physiology*
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Protein Structure, Tertiary
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RNA / metabolism
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RNA, Ribosomal, 23S / genetics
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RNA, Ribosomal, 23S / metabolism
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RNA-Binding Proteins / genetics
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RNA-Binding Proteins / metabolism
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Recombinant Fusion Proteins / metabolism
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Ribosomes / metabolism*
Substances
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Bacterial Proteins
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Carrier Proteins
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Cetrimonium Compounds
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Detergents
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RNA, Ribosomal, 23S
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RNA-Binding Proteins
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Recombinant Fusion Proteins
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RNA
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Cetrimonium