Related Experiment Video
Updated: Jun 1, 2026
11:14
Mass Spectrometric Approaches to Study Protein Structure and Interactions in Lyophilized Powders
Published on: April 14, 2015
Measurement of SDS Micelle-Peptide Association Using (1)H NMR Chemical Shift Analysis and Pulsed-Field Gradient NMR
1Department of Chemistry, University of Kansas, Lawrence, Kansas 66045.
Analytical Chemistry
|June 8, 2011
Summary
This study investigated how two peptides, glycyl-histidyl-glycine (GHG) and phenylalanyl-histidyl-phenylalanine (FHF), interact with SDS micelles. Researchers found that GHG binds to micelles, while the more hydrophobic FHF associates strongly, with minimal impact on micelle concentration.
Area of Science:
- Biophysical Chemistry
- Supramolecular Chemistry
- NMR Spectroscopy
Background:
- Understanding peptide-surfactant interactions is crucial for drug delivery and biomaterial design.
- Sodium dodecyl sulfate (SDS) micelles are common models for biological membranes.
- Tripeptides like GHG and FHF offer simple models for studying peptide-micelle binding.
Purpose of the Study:
- To investigate the binding of glycyl-histidyl-glycine (GHG) and phenylalanyl-histidyl-phenylalanine (FHF) to SDS micelles.
- To determine the binding affinity and assess the impact of these peptides on SDS micelle formation.
- To elucidate the role of peptide hydrophobicity in micelle association.
Main Methods:
- Proton Nuclear Magnetic Resonance ((1)H NMR) chemical shift analysis.
- Pulsed-field gradient NMR spectroscopy to measure self-diffusion coefficients.
- Determination of critical micelle concentration (cmc) and binding equilibrium constants.
Main Results:
- GHG shows concentration-dependent chemical shift changes and decreased diffusion coefficients, indicating micelle binding with an equilibrium constant of 17 ± 1 M⁻¹.
- The more hydrophobic FHF peptide associates strongly with SDS micelles, preventing accurate determination of binding constants.
- Neither peptide significantly altered the SDS critical micelle concentration (cmc) or average micelle size, though FHF showed a slight decrease in cmc.
Conclusions:
- GHG reversibly binds to SDS micelles, with binding affinity quantifiable via NMR.
- FHF exhibits strong association with SDS micelles, highlighting the influence of peptide hydrophobicity.
- These findings contribute to understanding peptide-surfactant interactions in micellar systems.
Related Concept Videos
01:15NMR Spectroscopy: Chemical Shift Overview
The position of the absorption signal of a sample is reported relative to the position of the signal of tetramethylsilane (TMS), which is added as an internal reference while recording spectra. The difference between the absorption frequencies of the sample and TMS (in Hz) is divided by the spectrometer operating frequency (in MHz) to obtain a dimensionless quantity called the chemical shift. It is reported on the δ (delta) scale and expressed in parts per million.
For instance, the proton...
For instance, the proton...
01:27SDS-PAGE
Gel electrophoresis is a method that separates biological macromolecules like nucleic acids or proteins by forcing them to pass through a gel matrix under an electric field.
A variation of gel electrophoresis, termed polyacrylamide gel electrophoresis (PAGE), is commonly used for separating proteins according to their molecular size by passing them through a polyacrylamide gel. Because of the varying charges associated with amino acid side chains, PAGE can be used to separate intact proteins...
A variation of gel electrophoresis, termed polyacrylamide gel electrophoresis (PAGE), is commonly used for separating proteins according to their molecular size by passing them through a polyacrylamide gel. Because of the varying charges associated with amino acid side chains, PAGE can be used to separate intact proteins...
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
01:33Peptide Identification Using Tandem Mass Spectrometry
Tandem mass spectrometry, also known as MS/MS or MS2, is an analytical technique that employs two mass analyzers. Essentially it is a series of mass spectrometers that helps isolate a particular biomolecule and then helps study its chemical properties.
This technique helps gather information regarding the protein from which the peptide was obtained and to study the peptides’ amino acid sequence. Identifying peptides from a complex mixture is an important component of the growing field of...
This technique helps gather information regarding the protein from which the peptide was obtained and to study the peptides’ amino acid sequence. Identifying peptides from a complex mixture is an important component of the growing field of...