SecYEG assembles into a tetramer to form the active protein translocation channel
Open Access
- 1 March 2000
- journal article
- research article
- Published by Springer Nature in The EMBO Journal
- Vol. 19 (5), 852-861
- https://doi.org/10.1093/emboj/19.5.852
Abstract
Translocase mediates preprotein translocation across the Escherichia coli inner membrane. It consists of the SecYEG integral membrane protein complex and the peripheral ATPase SecA. Here we show by functional assays, negative‐stain electron microscopy and mass measurements with the scanning transmission microscope that SecA recruits SecYEG complexes to form the active translocation channel. The active assembly of SecYEG has a side length of 10.5 nm and exhibits an ∼5 nm central cavity. The mass and structure of this SecYEG as well as the subunit stoichiometry of SecA and SecY in a soluble translocase–precursor complex reveal that translocase consists of the SecA homodimer and four SecYEG complexes.Keywords
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