Related Experiment Video
Updated: Jun 13, 2026

Construction of Cyclic Cell-Penetrating Peptides for Enhanced Penetration of Biological Barriers
Published on: September 19, 2022
Cyclization of peptides through a urea bond: application to the Arg-Gly-Asp tripeptide
Julien Schmidt1, Véronique Garambois, Luc Rocheblave
1Institut de Recherche en Cancérologie de Montpellier, Université Montpellier1, Montpellier, France.
Abstract:
Various synthetic cyclopeptides bind different cellular proteins with high affinity and specificity. In this study, we designed a new series of cyclic tetrapeptides containing the RGD sequence, a ligand for the alpha(v)beta(3) integrin receptor, in which the ring closure was performed through a urea bond between the alpha-amino group of the peptide and either the alpha- or the epsilon-amino group of an additional lysine. Interestingly, we showed that the urea-closed peptide had a higher affinity for alpha(v)beta(3) receptors than a reference pentacyclopeptide. Moreover, the synthetic strategy allows coupling of the resulting cyclic tetrapeptide through the carboxylic acid moiety of its lysine residue to fluorescent molecules or drugs. In addition, this strategy could be easily adapted for the cyclization of any other peptides.
Related Concept Videos
Peptide Bonds
Urea Cycle
Preparation of Amides
The DCC-promoted synthesis of amides begins with the protonation of DCC by carboxylic acid. The protonation makes it a better acceptor. Next, the addition of carboxylate to the protonated carbodiimide gives a reactive acylating agent.
Subsequently, the amine acts as a nucleophile that attacks the acylating agent to form a tetrahedral intermediate. In the...
Protein Folding Quality Check in the RER
Protein Folding
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
Amino Acid Catabolism

