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Updated: Aug 14, 2026

Production of Disulfide-stabilized Transmembrane Peptide Complexes for Structural Studies
Published on: March 6, 2013
Distance between phosphine-sulfide sidechains of a disubstituted peptide by DRAMA 31P NMR
C A Klug1, D R Studelska, G Chen
1Department of Chemistry, Washington University, St. Louis, MO 63130, USA.
Dipolar Restoration at the Magic Angle (DRAMA) measured a 7.4 Å distance between phosphorus atoms in a helical peptide. Matrix isolation reduced linewidth, indicating less heterogeneity in the peptide
Area of Science:
- Solid-state Nuclear Magnetic Resonance (NMR) spectroscopy.
- Biophysical chemistry.
- Structural biology.
Background:
- Phosphine-sulfide substituted peptides are valuable for structural studies.
- Understanding peptide structure and dynamics in different environments is crucial.
- Heterogeneity in bulk samples can complicate structural analysis.
Purpose of the Study:
- To measure the internuclear distance between 31P nuclei in a helical peptide using DRAMA.
- To investigate the effect of sample environment (bulk vs. matrix-isolated) on peptide structure and dynamics.
- To assess sample heterogeneity in different states.
Main Methods:
- Dipolar Restoration at the Magic Angle (DRAMA) was employed to measure 31P-31P distances.
- A 12-residue helical peptide with phosphine-sulfide sidechains was synthesized.
- Peptides were analyzed in both lyophilized bulk and matrix-isolated states (poly(ethylene glycol) and sucrose).
Main Results:
- A consistent 31P-31P internuclear distance of 7.4 Å was determined for both bulk and matrix-isolated peptides.
- The 31P linewidth was significantly greater (by an order of magnitude) for the bulk peptide compared to the matrix-isolated peptide.
- The observed linewidth difference suggests charge and hydration heterogeneity in the bulk state.
Conclusions:
- DRAMA is effective for determining internuclear distances in peptides.
- Matrix isolation can reduce sample heterogeneity, leading to narrower spectral lines.
- The structural integrity of the peptide, as indicated by the internuclear distance, is maintained across different sample preparations.
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