Direct arginine modification in native peptides and application to chemical probe development

Area of Science:

• Chemical Biology
• Organic Chemistry
• Biochemistry

Background:

• Peptide modification is crucial for biochemical research and drug development.
• Targeted labeling of specific amino acid residues in peptides remains a challenge.
• Arginine residues are prevalent in biologically active peptides and proteins.

Purpose of the Study:

• To develop an efficient and direct method for labeling the arginine guanidinium group in native peptides.
• To enable late-stage diversification of peptides with various reporter molecules.
• To demonstrate the utility of this method in biological applications.

Main Methods:

• Direct modification of the Arg guanidinium group under mild conditions.
• Utilizing various reporter groups including fluorophores and biotin.
• Assessing the compatibility with other common amino acid residues.

Main Results:

• An efficient method for direct arginine labeling in native peptides was established.
• The procedure is operationally simple and tolerates diverse amino acids (His, Ser, Trp, Tyr, Glu).
• Limitations were identified for cysteine and free amine residues.
• Successful labeling of leuprolide and microcystin was demonstrated.

Conclusions:

• This method provides a straightforward approach for arginine modification in peptides.
• It serves as a valuable tool for late-stage diversification and biological applications.
• The technique facilitates the monitoring of biologically relevant molecules like drugs and toxins.