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Synthesis of cyclic tryptathionine peptides
G Zanotti1, B Beijer, T Wieland
1C.N.R. Institute of Pharmaceutical Chemistry, University La Sapienza, Rome, Italy.
International Journal of Peptide and Protein Research
|September 1, 1987
Summary
Researchers synthesized cyclic thioether tripeptides to study amino acid configuration effects on peptide conformation. D-cysteine analogues exhibited distinct CD spectra, and a dimeric hexapeptide showed positive helicity, forming a copper complex.
Area of Science:
- Peptide Chemistry
- Structural Biology
- Biophysical Chemistry
Background:
- The helicity of phallotoxins' tryptathionine moiety is known.
- Understanding amino acid configuration's impact on cyclic peptide conformation is crucial.
Purpose of the Study:
- To investigate how amino acid configuration influences cyclic peptide conformation.
- To synthesize and characterize analogue thioether tripeptides.
Main Methods:
- Synthesis of six analogue thioether tripeptides with L- and D-amino acids.
- Circular Dichroism (CD) spectroscopy to analyze peptide conformation.
- Cyclization and dimerization reactions to form cyclic hexapeptides.
Main Results:
- Synthesized analogues showed CD spectra similar to each other, mirroring phalloidin's negative helicity.
- D-cysteine containing peptides displayed distinct CD spectra with positive ellipticity around 270 nm.
- A dimeric cyclic hexapeptide formed, exhibiting positive helicity and strong Cu2+ complexation.
Conclusions:
- Amino acid configuration significantly impacts cyclic peptide helicity.
- D-cysteine incorporation alters conformational properties.
- Dimeric thioether peptides can form stable metal complexes.