Peptide Splicing in the Proteasome Creates a Novel Type of Antigen with an Isopeptide Linkage.

ABSTRACT: The proteasome is able to create spliced Ags, in which two distant parts of a protein are excised and ligated together to form a novel peptide, for presentation by MHC class I molecules. These noncontiguous epitopes are generated via a transpeptidation reaction catalyzed by the proteasomal active sites. Transpeptidation reactions in the proteasome follow explicit rules and occur particularly efficiently when the C-terminal ligation partner contains a lysine or arginine residue at the site of ligation. Lysine contains two amino groups that theoretically may both participate in ligation reactions, implying that potentially not only peptide but also isopeptide linkages could be formed. Using nuclear magnetic resonance spectroscopy, we demonstrate in the present study that the proteasome can u

SUBMITTER: Berkers CR 

PROVIDER: S-EPMC4642838 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature