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Using SecM Arrest Sequence as a Tool to Isolate Ribosome Bound Polypeptides
09:42

Using SecM Arrest Sequence as a Tool to Isolate Ribosome Bound Polypeptides

Published on: June 19, 2012

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The SecM arrest peptide traps a pre-peptide bond formation state of the ribosome

Felix Gersteuer1, Martino Morici1, Sara Gabrielli2

  • 1Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, 20146, Hamburg, Germany.

Nature Communications
|March 20, 2024
PubMed

Insights

The SecM arrest peptide halts protein production by stabilizing tRNA in the ribosome. A pulling force on the nascent chain can release this translational arrest, a mechanism relevant to bacterial protein localization.

Area of Science:

  • Molecular Biology
  • Structural Biology
  • Biochemistry

Background:

  • Nascent polypeptide chains regulate gene expression through translational stalling.
  • The E. coli secretion monitor (SecM) arrest peptide exemplifies this, controlling SecA expression for protein translocation.
  • SecA is an ATPase crucial for protein insertion via the SecYEG translocon.

Purpose of the Study:

  • To determine the structural mechanism of SecM-mediated translational arrest.
  • To investigate how pulling forces on the SecM nascent chain relieve this arrest.

Main Methods:

  • X-ray crystallography at 2.0 Å resolution to visualize the stalled ribosome.
  • Molecular dynamics simulations to study the arrest and relief mechanisms.

Main Results:

  • The structure reveals SecM stabilizes Pro-tRNA in the A-site, inhibiting peptide bond formation.
  • Molecular dynamics simulations show pulling on the SecM chain can relieve the arrest.

Conclusions:

  • SecM arrest involves specific tRNA stabilization, preventing peptide bond formation.
  • Mechanical force can release SecM-mediated translational arrest.
  • These mechanisms are likely conserved for other bacterial arrest peptides regulating protein localization.

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