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Updated: Aug 14, 2026

A G-quadruplex DNA-affinity Approach for Purification of Enzymatically Active G4 Resolvase1
11:25

A G-quadruplex DNA-affinity Approach for Purification of Enzymatically Active G4 Resolvase1

Published on: March 18, 2017

An intrahelical salt bridge within the trigger site stabilizes the GCN4 leucine zipper

R A Kammerer1, V A Jaravine, S Frank

  • 1Departments of Biophysical Chemistry and Structural Biology, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.

The Journal of Biological Chemistry
|January 13, 2001
PubMed

Insights

A key salt bridge stabilizes the GCN4 leucine zipper

Area of Science:

  • Protein structure and folding
  • Biophysics
  • Molecular biology

Background:

  • The GCN4 leucine zipper forms a parallel two-stranded coiled coil.
  • A helical trigger segment is essential for coiled coil formation.

Purpose of the Study:

  • Investigate the role of an intrahelical salt bridge in stabilizing the GCN4 trigger segment.
  • Determine the effect of disrupting this salt bridge on GCN4 dimer stability and folding.

Main Methods:

  • Site-directed mutagenesis to remove the salt bridge.
  • Nuclear magnetic resonance (NMR) spectroscopy to assess structural changes.
  • Analysis of dimeric structure stability.

Main Results:

  • A single amino acid mutation removing the salt bridge caused minor backbone changes in the dimer.
  • The mutation significantly destabilized the overall dimeric structure.
  • The helical trigger segment's secondary structure is stabilized by the salt bridge.

Conclusions:

  • The intrahelical salt bridge is crucial for stabilizing the GCN4 trigger segment's helical structure.
  • Disruption of the salt bridge destabilizes the GCN4 coiled coil dimer.
  • Findings support a hierarchical folding model where trigger segment helix formation precedes dimerization.

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