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Forces on Nascent Polypeptides during Membrane Insertion and Translocation via the Sec Translocon

Journal Article · · Biophysical Journal
 [1];  [2];  [2];  [2];  [1]
  1. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  2. Stockholm Univ. (Sweden)
During ribosomal translation, nascent polypeptide chains (NCs) undergo a variety of physical processes that determine their fate in the cell. This study utilizes a combination of arrest peptide experiments and coarse-grained molecular dynamics to measure and elucidate the molecular origins of forces that are exerted on NCs during cotranslational membrane insertion and translocation via the Sec translocon. The approach enables deconvolution of force contributions from NC-translocon and NC-ribosome interactions, membrane partitioning, and electrostatic coupling to the membrane potential. In particular, we show that forces due to NC-lipid interactions provide a readout of conformational changes in the Sec translocon, demonstrating that lateral gate opening only occurs when a sufficiently hydrophobic segment of NC residues reaches the translocon. The combination of experiment and theory introduced here provides a detailed picture of the molecular interactions and conformational changes during ribosomal translation that govern protein biogenesis.
Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Univ. of California, Oakland, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
Grant/Contract Number:
AC02-05CH11231
OSTI ID:
1543513
Journal Information:
Biophysical Journal, Journal Name: Biophysical Journal Journal Issue: 10 Vol. 115; ISSN 0006-3495
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

References (48)

Cryo-EM structure of the ribosome–SecYE complex in the membrane environment journal April 2011
Charge-driven dynamics of nascent-chain movement through the SecYEG translocon journal January 2015
The Sec61p Complex Mediates the Integration of a Membrane Protein by Allowing Lipid Partitioning of the Transmembrane Domain journal July 2000
Decrypting protein insertion through the translocon with free-energy calculations journal July 2016
Divergent stalling sequences sense and control cellular physiology journal February 2010
Structure of the Mammalian Ribosome-Sec61 Complex to 3.4 Å Resolution journal June 2014
Long-Timescale Dynamics and Regulation of Sec-Facilitated Protein Translocation journal October 2012
A Link between Integral Membrane Protein Expression and Simulated Integration Efficiency journal August 2016
Mechanisms of Integral Membrane Protein Insertion and Folding journal March 2015
Transmembrane helices before, during, and after insertion journal August 2005
The Sec61p Complex Mediates the Integration of a Membrane Protein by Allowing Lipid Partitioning of the Transmembrane Domain journal July 2000
Direct Simulation of Early-Stage Sec-Facilitated Protein Translocation journal August 2012
On the Nature of the Apparent Free Energy of Inserting Amino Acids into Membrane through the Translocon journal October 2013
X-ray structure of a protein-conducting channel journal December 2003
Recognition of transmembrane helices by the endoplasmic reticulum translocon journal January 2005
Protein translocation across the eukaryotic endoplasmic reticulum and bacterial plasma membranes journal November 2007
Structures of the Sec61 complex engaged in nascent peptide translocation or membrane insertion journal February 2014
Lateral opening of the bacterial translocon on ribosome binding and signal peptide insertion journal October 2014
Dual-topology insertion of a dual-topology membrane protein journal August 2015
Experimentally determined hydrophobicity scale for proteins at membrane interfaces journal October 1996
A biphasic pulling force acts on transmembrane helices during translocon-mediated membrane integration journal September 2012
Cotranslational folding of spectrin domains via partially structured states journal January 2017
Theory, analysis, and interpretation of single-molecule force spectroscopy experiments journal October 2008
Hydrophobically stabilized open state for the lateral gate of the Sec translocon journal March 2010
Lateral opening of a translocon upon entry of protein suggests the mechanism of insertion into membranes journal September 2010
Cotranslational folding of membrane proteins probed by arrest-peptide–mediated force measurements journal August 2013
Functional asymmetry within the Sec61p translocon journal November 2013
Improving membrane protein expression by optimizing integration efficiency journal September 2017
Mutations in the Sec61p Channel Affecting Signal Sequence Recognition and Membrane Protein Topology journal September 2007
Improving membrane protein expression by optimizing integration efficiency journal September 2017
Mutations in the Sec61p Channel Affecting Signal Sequence Recognition and Membrane Protein Topology journal September 2007
A gating motif in the translocation channel sets the hydrophobicity threshold for signal sequence function journal December 2012
Protein translocation mutants defective in the insertion of integral membrane proteins into the endoplasmic reticulum. journal February 1992
The Hydrophobic Core of the Sec61 Translocon Defines the Hydrophobicity Threshold for Membrane Integration journal May 2010
Molecular mechanism of signal sequence orientation in the endoplasmic reticulum journal July 2003
XSEDE: Accelerating Scientific Discovery journal September 2014
XSEDE: Accelerating Scientific Discovery journal September 2014
Mechanical force releases nascent chain-mediated ribosome arrest in vitro and in vivo journal April 2015
Energetics of Membrane Protein Folding journal May 2014
Membrane Protein Insertion at the Endoplasmic Reticulum journal November 2011
Protein Translocation Across the Bacterial Cytoplasmic Membrane journal June 2008
Structurally detailed coarse-grained model for Sec-facilitated co-translational protein translocation and membrane integration journal March 2017
Unicycler: Resolving bacterial genome assemblies from short and long sequencing reads journal June 2017
Cotranslational folding of spectrin domains via partially structured states. journalarticle January 2017
The hydrophobic core of the Sec61 translocon defines the hydrophobicity threshold for membrane integration text January 2010
Regulation of multispanning membrane protein topology via post-translational annealing journal September 2015
Mutational scanning reveals the determinants of protein insertion and association energetics in the plasma membrane journal January 2016
Regulation of multispanning membrane protein topology via post-translational annealing journal September 2015

Cited By (4)

A snapshot of membrane protein insertion journal September 2019
Domain topology, stability, and translation speed determine mechanical force generation on the ribosome journal March 2019
Cotranslational folding stimulates programmed ribosomal frameshifting in the alphavirus structural polyprotein journal May 2020
Partially inserted nascent chain unzips the lateral gate of the Sec translocon journal August 2019

Figures / Tables (3)


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