Abstract
The marine Gram-negative bacteria Rhodopirellula baltica and Oceanicaulis alexandrii have, in contrast to Escherichia coli, membrane insertases with extended positively charged C-terminal regions similar to the YidC homologues in mitochondria and Gram-positive bacteria. We have found that chimeric forms of E. coli YidC fused to the C-terminal YidC regions from the marine bacteria mediate binding of YidC to ribosomes and therefore may have a functional role for targeting a nascent protein to the membrane. Here, we show in E. coli that an extended C-terminal region of YidC can compensate for a loss of SRP-receptor function in vivo. Furthermore, the enhanced affinity of the ribosome to the chimeric YidC allows the isolation of a ribosome nascent chain complex together with the C-terminally elongated YidC chimera. This complex was visualized at 8.6 Å by cryo-electron microscopy and shows a close contact of the ribosome and a YidC monomer.
© 2013 John Wiley & Sons Ltd.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Alphaproteobacteria / genetics
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Alphaproteobacteria / metabolism
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Bacterial Proteins / chemistry*
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism*
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Cryoelectron Microscopy
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Escherichia coli / genetics
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Escherichia coli / metabolism
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Escherichia coli Proteins / chemistry
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Escherichia coli Proteins / genetics
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Escherichia coli Proteins / metabolism*
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Membrane Proteins / chemistry
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Membrane Proteins / metabolism
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Models, Molecular
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Planctomycetales / genetics
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Planctomycetales / metabolism*
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Protein Conformation
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Protein Structure, Quaternary
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Protein Structure, Tertiary
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Receptors, Cytoplasmic and Nuclear / chemistry
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Receptors, Cytoplasmic and Nuclear / genetics
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Receptors, Cytoplasmic and Nuclear / metabolism*
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Receptors, Peptide / metabolism*
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Recombinant Fusion Proteins / chemistry
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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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Escherichia coli Proteins
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FtsY protein, Bacteria
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Membrane Proteins
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Receptors, Cytoplasmic and Nuclear
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Receptors, Peptide
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Recombinant Fusion Proteins
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signal peptide receptor