Chemically Diverse Helix-Constrained Peptides Using Selenocysteine Crosslinking.

Area of Science:

• Biochemistry
• Organic Chemistry
• Peptide Science

Background:

• Bioactive peptides often require specific structures, like helices, for function.
• Inducing stable helical structures in peptides can be challenging under mild conditions.
• Cysteine cross-linking is common but can be slow or require harsh conditions.

Purpose of the Study:

• To describe a novel method for inducing helicity in bioactive peptides.
• To explore the use of selenocysteine for efficient peptide cross-linking.
• To demonstrate the tailoring of peptide structure using variable cross-linkers.

Main Methods:

• Incorporation of selenocysteine residues into a p53 peptide sequence.
• Cross-linking of selenocysteine pairs using alkylating agents with varying properties.
• Analysis of peptide structure and cross-linking efficiency under mild aqueous conditions.

Main Results:

• Selenocysteine demonstrated higher reactivity than cysteine for cross-linking.
• Rapid and efficient cross-linking occurred under mild, aqueous conditions with unprotected peptides.
• Diverse helical peptide structures were achieved by varying cross-linker topology and electrophilicity.
• Selenoether bond formation was facile and enabled structural control.

Conclusions:

• Selenocysteine offers a superior alternative to cysteine for rapid peptide cross-linking.
• This method provides a versatile platform for designing structurally defined helical peptides.
• The approach facilitates the development of tailored bioactive peptides with specific conformations.