Abstract
An oligomer of the Sec61 trimeric complex is thought to form the protein-conducting channel for protein transport across the endoplasmic reticulum. A purified yeast Sec61 complex bound to monomeric yeast ribosomes as an oligomer in a saturable fashion. Cryo-electron microscopy of the ribosome-Sec61 complex and a three-dimensional reconstruction showed that the Sec61 oligomer is attached to the large ribosomal subunit by a single connection. Moreover, a funnel-shaped pore in the Sec61 oligomer aligned with the exit of a tunnel traversing the large ribosomal subunit, strongly suggesting that both structures function together in the translocation of proteins across the endoplasmic reticulum membrane.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Binding Sites
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Biological Transport
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Endoplasmic Reticulum, Rough / metabolism
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Fungal Proteins / chemistry
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Fungal Proteins / metabolism
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Fungal Proteins / ultrastructure
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Image Processing, Computer-Assisted
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Macromolecular Substances
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Membrane Proteins / chemistry
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Membrane Proteins / metabolism
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Membrane Proteins / ultrastructure*
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Membrane Transport Proteins
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Microscopy, Electron
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Ribosomes / chemistry
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Ribosomes / metabolism
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Ribosomes / ultrastructure*
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SEC Translocation Channels
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Saccharomyces cerevisiae / chemistry
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Saccharomyces cerevisiae / ultrastructure
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Saccharomyces cerevisiae Proteins
Substances
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Fungal Proteins
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Macromolecular Substances
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Membrane Proteins
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Membrane Transport Proteins
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SEC Translocation Channels
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SEC61 protein, S cerevisiae
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Saccharomyces cerevisiae Proteins