Mechanisms of aminopeptidase function

Aminopeptidases in the ER (endoplasmic reticulum) of the cell perform the last stage of trimming of antigenic peptide precursors before loading the mature antigenic peptides onto MHC class I molecules.

ERAP1 (ER aminopeptidase 1) trims antigenic peptide precursors from their N-terminus, one residue at a time, stopping at the correct peptide length required for MHC loading:

We are currently investigating the mechanism that ERAP1 and its homologous enzymes ERAP2 and IRAP utilise to generate antigenic peptides, using a variety of molecular biology approaches, hopping to unravel the exact role of the enzyme in antigenic peptide selection (for examples read this paper and this paper).