Figure 5.

Schematics depicting characteristics of proteasome-catalyzed peptide splicing. (A) Diagram illustrating the characteristics of forward PCPS events. (B) Diagram illustrating the characteristics of reverse PCPS events occurring over cis-splicing distances >0 aa. (C) Diagram illustrating the characteristics of reverse PCPS events occurring with no intervening cis-splicing distance. In (A–C), Red arrows indicate splicing events. Amino acids typically acting as O-acyl enzyme intermediates or nucleophilic free amines as defined in splice site signatures (Figure 4) are shown in single letter code at the end and start of N- and C-terminal splice partners (respectively).