On-resin synthesis of Lanreotide epimers and studies of their structure-activity relationships.

Peptide drugs often accompany epimeric impurities (isomers). Therefore, efficient chemical synthesis of epimers is critical to identify them correctly and investigate their biological activities. Here, we report the rapid synthesis and structure-activity relationship (SAR) studies of eight possible epimers of a somatostatin synthetic analog (SSA), lanreotide (LAN).

Harnessing a bis-electrophilic boronic acid lynchpin for azaborolo thiazolidine (ABT) grafting in cyclic peptides.

Chemical modifications of native peptides have significantly advanced modern drug discovery in recent decades. On this front, the installation of multitasking molecular grafts onto macrocyclic peptides offers numerous opportunities in biomedical applications. Here, we showcase a new class of borono-cyclic peptides featuring an azaborolo thiazolidine (ABT) graft, which can be readily assembled utilizing a bis-electrophilic boronic acid lynchpin while harnessing the inherent reactivity difference (>10 M s) between the N-terminal cysteine and backbone cysteine for rapid and highly regioselective macrocyclization (∼1 h) under physiological conditions.

Integrating a covalent probe with ubiquicidin fragment enables effective bacterial infection imaging.

Developing potent and novel bacterial imaging agents remains formidable due to the rapid development of bacterial resistance. Ubiquicidin and its derivatives are the most studied antimicrobial peptides that bind to anionic membranes of a broad range of bacterial pathogens. Studies reveal that UBI (29-41) labeled with Tc and Ga could distinguish sterile inflammation from infection.