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Helical Structure of Recombinant Melittin
- Source :
- The journal of physical chemistry. B. 123(2)
- Publication Year :
- 2018
-
Abstract
- Melittin is an extensively studied, 26-residue toxic peptide from honey bee venom. Because of its versatility in adopting a variety of secondary (helix or coil) and quaternary (monomer or tetramer) structures in various environments, melittin has been the focus of numerous investigations as a model peptide in protein folding studies as well as in studies involving binding to proteins, lipids, and polysaccharides. A significant body of evidence supports the view that melittin binds to these macromolecules in a predominantly helical conformation, but detailed structural knowledge of this conformation is lacking. In this report, we present nuclear magnetic resonance (NMR)-based structural insights into the helix formation of recombinant melittin in the presence of trifluoroethanol (TFE): a known secondary structure inducer in peptides. These studies were performed at neutral pH, with micromolar amounts of the peptide. Using nuclear Overhauser effect (NOE)-derived distance restraints from three-dimensional NMR spectra, we determined the atomic resolution solution NMR structure of recombinant melittin bearing a TFE-stabilized helix. To circumvent the complications with structure determination of small peptides with high conformational flexibility, we developed a workflow for enhancing proton NOEs by increasing the viscosity of the medium. In the TFE-containing medium, recombinant monomeric melittin forms a long, continuous helical structure, which consists of the N- and C-terminal α-helices and the noncanonical 3(10)-helix in the middle. The noncanonical 3(10)-helix is missing in the previously solved X-ray structure of tetrameric melittin and the NMR structure of melittin in methanol. Melittin’s structure in TFE-containing medium provides insights into melittin’s conformational transitions, which are relevant to the peptide’s interactions with its biological targets.
- Subjects :
- 0301 basic medicine
Glycerol
Protein Conformation, alpha-Helical
Stereochemistry
Peptide
Nuclear Overhauser effect
010402 general chemistry
01 natural sciences
complex mixtures
Melittin
Article
03 medical and health sciences
chemistry.chemical_compound
Protein structure
Tetramer
Materials Chemistry
Escherichia coli
Amino Acid Sequence
Physical and Theoretical Chemistry
Protein secondary structure
Nuclear Magnetic Resonance, Biomolecular
chemistry.chemical_classification
Carbon Isotopes
Nitrogen Isotopes
Chemistry
Viscosity
technology, industry, and agriculture
Water
Hydrogen Bonding
Trifluoroethanol
Melitten
Recombinant Proteins
0104 chemical sciences
Surfaces, Coatings and Films
030104 developmental biology
Helix
Protein folding
lipids (amino acids, peptides, and proteins)
Subjects
Details
- ISSN :
- 15205207
- Volume :
- 123
- Issue :
- 2
- Database :
- OpenAIRE
- Journal :
- The journal of physical chemistry. B
- Accession number :
- edsair.doi.dedup.....c8f7a806106947aa4f107e421e6515a3