Binding of SecA ATPase monomers and dimers to lipid vesicles

Roussel, G.; White, Stephen H.

doi:10.1016/j.bbamem.2019.183112

Cited by 10 publications

(22 citation statements)

References 58 publications

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“…The model assumes a monomeric SecA conformation on the membrane surface because (i) complete dissociation of aqueous SecA dimers has previously been observed in the presence of liposomes containing acidic phospholipids, 25 and (ii) articially stabilized SecA dimers are unable to bind to the membrane surface. 38,39 The overall SecA abundance on the membrane was comparable at different [KCl], as indicated by the size of the SPR signal (Fig. S2C †).…”

Section: Resultsmentioning

confidence: 75%

Interaction of the motor protein SecA and the bacterial protein translocation channel SecYEG in the absence of ATP

et al. 2020

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Section: Resultsmentioning

confidence: 75%

Interaction of the motor protein SecA and the bacterial protein translocation channel SecYEG in the absence of ATP

et al. 2020

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“…The model assumes a monomeric SecA conformation on the membrane surface because (i) complete dissociation of aqueous SecA dimers has previously been observed in the presence of liposomes containing acidic phospholipids 25 , and (ii) artificially stabilized SecA dimers are unable to bind to the membrane surface. 36,37 The overall SecA abundance on the membrane was comparable at different [KCl], as indicated by the size of the SPR signal ( Fig S2).…”

Section: Resultsmentioning

confidence: 80%

“…3 The transition between state I and II may be associated with the insertion of the N-terminus into the lipid membrane as previously suggested. 4 The model does not refer to the SecA dimer, because it is (i) apparently unable to bind to the membrane surface 36,37 , and (ii) dissociates the presence of acidic lipids 25 . Reports about the functionality of covalently linked SecA dimers 5,42 do not challenge the conclusion, because they do not contain evidence that the dimer may bind to the lipid in the absence of SecYEG.…”

Section: Discussionmentioning

confidence: 99%

Interaction of the Motor Protein SecA and the Bacterial Protein Translocation Channel SecYEG in the Absence of ATP

Winkler

Karner

Hörner

et al. 2019

Preprint

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16Translocation of many secretory proteins through the bacterial plasma membrane is facilitated by 17 a complex of the protein translocase SecYEG with the motor protein SecA. The ATP-free complex 18 is unstable in detergent, raising the question how SecA may perform several rounds of ATP 19 hydrolysis without being released. Here we show that dual recognition of (i) SecYEG and (ii) acidic 20 lipids in its immediate vicinity confers an apparent nanomolar affinity. As a result the complex 21 between SecA and reconstituted SecYEG may be stable for tens of seconds as visualized by high-22 27 28 29 30

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“…SecA:lipid binding is largely mediated by the N-terminal amphipathic helix of the ATPase: The helix is essential for interactions with the membrane, where it extensively binds anionic lipids via lysine and arginine residues at the polar side [26,35,36]. Further partitioning of the helix into the lipid leaflet, however, must rely on interactions with the hydrophobic fatty acids.…”

Section: Discussionmentioning

confidence: 99%

“…Despite the extensive research, neither the quaternary state and dynamics of SecA nor its processivity in translocation have been clarified [38][39][40]. Recent reports have suggested that the oligomeric state of the membrane-bound SecA depends on the membrane lipid composition [35,41], so it deserves further evaluation, whether UFAmediated lipid packing influences SecA dynamics or, potentially, diffusion at the membrane interface.…”

Section: Discussionmentioning

confidence: 99%

Unsaturated fatty acids augment protein transport via the SecA:SecYEG translocon

Kamel

Löwe

Schott‐Verdugo

et al. 2021

Preprint

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The translocon SecYEG forms the primary protein-conducting channel in the cytoplasmic membrane of bacteria, and the associated ATPase SecA provides the energy for the transport of secretory and cell envelope protein precursors. The translocation requires negative charge at the lipid membrane surface, but its dependence on the properties of the membrane hydrophobic core is not known. Here, we demonstrate that SecA:SecYEG-mediated protein transport is immensely stimulated by unsaturated fatty acids (UFAs). Furthermore, UFA-rich tetraoleoyl-cardiolipin, but not bis(palmitoyloleoyl)-cardiolipin, facilitate the translocation via the monomeric translocon. Biophysical analysis and molecular dynamics simulations show that UFAs determine the loosely packed membrane interface, where the N-terminal amphipathic helix of SecA docks. While UFAs do not affect the translocon folding, they promote SecA binding to the membrane, and the effect is enhanced manifold at elevated ionic strength. Tight SecA:lipid interactions convert into the augmented translocation. As bacterial cells actively change their membrane composition in response to their habitat, the modulation of SecA:SecYEG activity via the fatty acids may be crucial for protein secretion over a broad range of environmental conditions.

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Binding of SecA ATPase monomers and dimers to lipid vesicles

Cited by 10 publications

References 58 publications

Interaction of the motor protein SecA and the bacterial protein translocation channel SecYEG in the absence of ATP

Interaction of the motor protein SecA and the bacterial protein translocation channel SecYEG in the absence of ATP

Interaction of the Motor Protein SecA and the Bacterial Protein Translocation Channel SecYEG in the Absence of ATP

Unsaturated fatty acids augment protein transport via the SecA:SecYEG translocon

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