Oligomeric states of the SecA and SecYEG core components of the bacterial Sec translocon

Rusch, Sharyn L.; Kendall, Debra A.

doi:10.1016/j.bbamem.2006.08.013

Cited by 29 publications

(26 citation statements)

References 98 publications

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“…This finding has been confirmed by thiol-cross-linking (11,12) and by cryoelectron microscopy analysis of the eukaryotic Sec complex bound to a translating ribosome (13). It is thus well-established that a single SecY copy is sufficient to form the translocation pathway, yet it remains mysterious that the channel exists as oligomers (14)(15)(16)(17).…”

mentioning

confidence: 51%

Two copies of the SecY channel and acidic lipids are necessary to activate the SecA translocation ATPase

Dalal

Chan

Sligar

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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The SecA ATPase associates with the SecY complex to push preproteins across the bacterial membrane. Because a single SecY is sufficient to create the conducting channel, the function of SecY oligomerization remains unclear. Here, we have analyzed the translocation reaction using nanodiscs. We show that one SecY copy is sufficient to bind SecA and the preprotein, but only the SecY dimer together with acidic lipids supports the activation of the SecA translocation ATPase. In discs, the dimer is predominantly arranged in a back-to-back manner and remains active even if a constituent SecY copy is defective for SecA binding. In membrane vesicles and in intact cells, the coproduction of two inactive SecYs, one for channel gating and the other for SecA binding, recreates a functional translocation unit. These results indisputably argue that the SecY dimer is crucial for the activation of SecA, which is necessary for preprotein transport.

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mentioning

confidence: 51%

Two copies of the SecY channel and acidic lipids are necessary to activate the SecA translocation ATPase

Dalal

Chan

Sligar

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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“…These conformational rearrangements convert SecA from a water-soluble dimeric protein to an integral membrane protein, whose oligomeric state is as yet unclear despite extensive effort. 82 The complex overall architecture of the cytoplasmic form of SecA, which represents the closed form, was first revealed at atomic resolution in a crystal structure of Bacillus subtilis SecA reported by Hunt et al 81 The structure showed the unique multiple domain organization of SecA ( Figure 4A). The motor domains of SecA (termed NBF in the figure) share homology with the super family II DEAD helicases, 83 which bind nucleotide at the interface between the two Using Signal Peptides to Explore Protein Export 313 motor domains.…”

Section: Seca Is Central To the Bacterial Sec Pathwaymentioning

confidence: 92%

Use of synthetic signal sequences to explore the protein export machinery

Clérico¹,

Maki²,

Gierasch³

2008

Biopolymers

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The information for correct localization of newly synthesized proteins in both prokaryotes and eukaryotes resides in self‐contained, often transportable targeting sequences. Of these, signal sequences specify that a protein should be secreted from a cell or incorporated into the cytoplasmic membrane. A central puzzle is presented by the lack of primary structural homology among signal sequences, although they share common features in their sequences. Synthetic signal peptides have enabled a wide range of studies of how these “zipcodes” for protein secretion are decoded and used to target proteins to the protein machinery that facilitates their translocation across and integration into membranes. We review research on how the information in signal sequences enables their passenger proteins to be correctly and efficiently localized. Synthetic signal peptides have made possible binding and crosslinking studies to explore how selectivity is achieved in recognition by the signal sequence‐binding receptors, signal recognition particle, or SRP, which functions in all organisms, and SecA, which functions in prokaryotes and some organelles of prokaryotic origins. While progress has been made, the absence of atomic resolution structures for complexes of signal peptides and their receptors has definitely left many questions to be answered in the future. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90: 307–319, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com

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“…47). We mapped the 20 SecA residues that were positive for SecY photocross-linking on to front-to-front and back-to-back models of the SecA⅐SecYEG complex that were made in silico (Fig.…”

Section: Resultsmentioning

confidence: 99%

Mapping of the SecA·SecY and SecA·SecG Interfaces by Site-directed in Vivo Photocross-linking

Das

Oliver

2011

Journal of Biological Chemistry

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Oligomeric states of the SecA and SecYEG core components of the bacterial Sec translocon

Cited by 29 publications

References 98 publications

Two copies of the SecY channel and acidic lipids are necessary to activate the SecA translocation ATPase

Two copies of the SecY channel and acidic lipids are necessary to activate the SecA translocation ATPase

Use of synthetic signal sequences to explore the protein export machinery

Mapping of the SecA·SecY and SecA·SecG Interfaces by Site-directed in Vivo Photocross-linking

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