Organometallic Chemistry Approach to Peptide Tricycles

Area of Science:

• Organometallic Chemistry
• Peptide Chemistry
• Bioconjugation

Background:

• Constrained peptide structures are valuable in drug discovery and materials science.
• Efficient methods for generating complex peptide architectures are needed.
• Gold-based reagents offer unique reactivity for bioconjugation.

Purpose of the Study:

• To develop a streamlined method for synthesizing constrained peptide tricycles using Au(III) chemistry.
• To create novel fluorescent macrocycles with potential as cellular probes.
• To investigate the utility of these constructs as cell markers.

Main Methods:

• Utilized tetrametallic Au(III)-based aryl reagents for selective bioconjugation with cysteine residues.
• Synthesized a library of constrained peptide tricycles from tetracysteine-containing linear peptides.
• Incorporated tetraphenylethylene core to generate fluorescent hybrid peptides.

Main Results:

• Achieved synthesis of constrained peptide tricycles in 25-55% yields.
• Demonstrated quantitative tricyclization conversion within five minutes at sub-millimolar peptide concentrations.
• Generated fluorescent macrocycles exhibiting robust solution-state emission.
• Identified these fluorescent peptides as selective luminogenic cell markers for cellular debris.

Conclusions:

• Au(III) organometallic chemistry provides an efficient route to constrained peptide tricycles.
• The developed fluorescent macrocycles are effective and selective markers for cellular debris.
• This approach offers a versatile platform for creating functional peptide-based materials.