Kinetic and Mechanistic Studies of Native Chemical Ligation with Phenyl α-Selenoester Peptides.

ABSTRACT: Native chemical ligation (NCL) ligates two unprotected peptides in an aqueous buffer. One of the fragments features a C-terminal α-thioester functional group, and the second bears an N-terminal cysteine. The reaction mechanism depicts two steps: an intermolecular thiol-thioester exchange resulting in a transient thioester, followed by an intramolecular S-to-N acyl shift to yield the final native peptide bond. Although this mechanism is well established, the direct observation of the transient thioester has been elusive because the fast intramolecular rearrangement prevents its accumulation. Here, the use of α-selenoester peptides allows a faster first reaction and an early buildup of the intermediate, enabling its quantification and the kinetic monitoring of the first and second ste

SUBMITTER: Sanchez-Campillo I 

PROVIDER: S-EPMC11600164 | biostudies-literature | 2024 Nov

REPOSITORIES: biostudies-literature