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Updated: Jul 8, 2026
10:09
Detection of Detergent-sensitive Interactions Between Membrane Proteins
Published on: March 7, 2018
Melittin interaction with sulfated cell surface sugars.
Gabriela Klocek1, Joachim Seelig
1Department of Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland.
Biochemistry
|January 29, 2008
Summary
Melittin binds to glycosaminoglycans (GAGs) like heparan sulfate (HS) via electrostatic and hydrophobic interactions, inducing an alpha-helical structure. This contrasts with magainin 2 and nisin Z, which do not bind GAGs.
Area of Science:
- Biochemistry
- Molecular Biology
- Biophysics
Background:
- Melittin, a cationic peptide, exhibits cytolytic and antimicrobial properties.
- Previous research focused on melittin's interaction with lipid membranes.
- Cell surfaces are often decorated with anionic glycosaminoglycans (GAGs).
Purpose of the Study:
- To investigate an alternative mechanism of melittin-cell membrane interaction via GAGs.
- To characterize the binding affinity and thermodynamics of melittin-GAG interactions.
- To compare melittin's GAG binding with that of other antimicrobial peptides.
Main Methods:
- Isothermal titration calorimetry (ITC) to quantify binding affinity and thermodynamics.
- Circular dichroism (CD) spectroscopy to assess conformational changes.
- Comparative analysis with magainin 2 and nisin Z binding to GAGs.
Main Results:
- Melittin exhibits high affinity for heparan sulfate (HS), dermatan sulfate, and heparin.
- Binding to HS involves both Coulombic and hydrophobic interactions, with a significant negative heat capacity change.
- Melittin adopts a predominantly alpha-helical structure upon binding to HS.
- Magainin 2 and nisin Z showed no detectable binding to HS.
Conclusions:
- Melittin interacts with cell surfaces through GAGs, offering an alternative to membrane perturbation.
- The binding induces a conformational change in melittin, suggesting a role in its biological activity.
- GAG binding specificity differs among antimicrobial peptides, highlighting distinct mechanisms of action.
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