Driving Forces of Translocation Through Bacterial Translocon SecYEG

Knyazev, Denis G.; Kuttner, Roland; Zimmermann, Mirjam; Sobakinskaya, E. A.; Pohl, Peter

doi:10.1007/s00232-017-0012-9

Cited by 27 publications

(26 citation statements)

References 106 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, a more likely explanation of our results is that positive charges at the N‐terminus of the nascent peptide interact with negative charges of the rRNA of the ribosome tunnel wall, which causes retention of the N‐terminus and inversion of TM1 within the tunnel upon continued peptide elongation. In vivo, the membrane potential may additionally influence topogenesis of membrane proteins in bacteria (Andersson & von Heijne, ; Cao et al , ; van der Laan et al , ; Knyazev et al , ). Movement of the nascent chain toward the tunnel exit and into the translocon requires that eventually the N‐terminus is released from the electrostatic interactions in the tunnel.…”

Section: Discussionmentioning

confidence: 99%

Co‐translational insertion and topogenesis of bacterial membrane proteins monitored in real time

2020

View full text Add to dashboard Cite

Integral membrane proteins insert into the bacterial inner membrane co‐translationally via the translocon. Transmembrane (TM) segments of nascent proteins adopt their native topological arrangement with the N‐terminus of the first TM (TM1) oriented to the outside (type I) or the inside (type II) of the cell. Here, we study TM1 topogenesis during ongoing translation in a bacterial in vitro system, applying real‐time FRET and protease protection assays. We find that TM1 of the type I protein LepB reaches the translocon immediately upon emerging from the ribosome. In contrast, the type II protein EmrD requires a longer nascent chain before TM1 reaches the translocon and adopts its topology by looping inside the ribosomal peptide exit tunnel. Looping presumably is mediated by interactions between positive charges at the N‐terminus of TM1 and negative charges in the tunnel wall. Early TM1 inversion is abrogated by charge reversal at the N‐terminus. Kinetic analysis also shows that co‐translational membrane insertion of TM1 is intrinsically rapid and rate‐limited by translation. Thus, the ribosome has an important role in membrane protein topogenesis.

show abstract

Section: Discussionmentioning

confidence: 99%

Co‐translational insertion and topogenesis of bacterial membrane proteins monitored in real time

2020

View full text Add to dashboard Cite

show abstract

“…The energy provided by SecA dependent hydrolysis of ATP is required for protein translocation of secreted proteins across the SecYEG channel 43 and large extramembrane domains of polytopic membrane proteins 44 . ΔΨ can contribute directly to translocation and drive translocation of preprotein residues or extramembrane domains containing large numbers of negatively charged amino acids electrophoretically [45][46][47] . SecDF may couple proton-motive force (PMF) to the release of the translocated polypeptides from SecYEG translocon 2 .…”

mentioning

confidence: 99%

Cardiolipin is required in vivo for the stability of bacterial translocon and optimal membrane protein translocation and insertion

Ryabichko

Ferreira

Vitrac

et al. 2020

Sci Rep

View full text Add to dashboard Cite

translocation of preproteins across the Escherichia coli inner membrane requires anionic lipids by virtue of their negative head-group charge either in vivo or in situ. However, available results do not differentiate between the roles of monoanionic phosphatidylglycerol and dianionic cardiolipin (CL) in this essential membrane-related process. To define in vivo the molecular steps affected by the absence of CL in protein translocation and insertion, we analyzed translocon activity, SecYEG stability and its interaction with SecA in an E. coli mutant devoid of CL. Although no growth defects were observed, co-and post-translational translocation of α-helical proteins across inner membrane and the assembly of outer membrane β-barrel precursors were severely compromised in CL-lacking cells. Components of proton-motive force which could impair protein insertion into and translocation across the inner membrane, were unaffected. However, stability of the dimeric SecYEG complex and oligomerization properties of SecA were strongly compromised while the levels of individual SecYEG translocon components, SecA and insertase YidC were largely unaffected. These results demonstrate that CL is required in vivo for the stability of the bacterial translocon and its efficient function in co-translational insertion into and translocation across the inner membrane of E. coli.

show abstract

“…While SecYEG provides the pathway for protein translocation, SecA affords part of the translocation energy by hydrolyzing ATP, the other part being provided by the proton motive force. 1 SecA gains access to the SecYEG complex via a lipid-bound intermediate state. 2 Its highly amphipathic N-terminal helix carries positively charged amino acids aligned on one side, and hydrophobic amino acids on the other which interact with negatively charged phospholipids.…”

Section: Introductionmentioning

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

Self Cite

View full text Add to dashboard Cite

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

show abstract

Driving Forces of Translocation Through Bacterial Translocon SecYEG

Cited by 27 publications

References 106 publications

Co‐translational insertion and topogenesis of bacterial membrane proteins monitored in real time

Co‐translational insertion and topogenesis of bacterial membrane proteins monitored in real time

Cardiolipin is required in vivo for the stability of bacterial translocon and optimal membrane protein translocation and insertion

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

Contact Info

Product

Resources

About