3se6
Crystal structure of the human Endoplasmic Reticulum Aminopeptidase 2
Structural highlights
FunctionERAP2_HUMAN Aminopeptidase that plays a central role in peptide trimming, a step required for the generation of most HLA class I-binding peptides. Peptide trimming is essential to customize longer precursor peptides to fit them to the correct length required for presentation on MHC class I molecules. Preferentially hydrolyzes the basic residues Arg and Lys.[1] [2] [3] Publication Abstract from PubMedEndoplasmic reticulum aminopeptidases ERAP1 and ERAP2 cooperate to trim a vast variety of antigenic peptide precursors to generate mature epitopes for binding to major histocompatibility class I molecules. We report here the first structure of ERAP2 determined at 3.08 A by X-ray crystallography. On the basis of residual electron density, a lysine residue has been modeled in the active site of the enzyme; thus, the structure corresponds to an enzyme-product complex. The overall domain organization is highly similar to that of the recently determined structure of ERAP1 in its closed conformation. A large internal cavity adjacent to the catalytic site can accommodate large peptide substrates. The ERAP2 structure provides a structural explanation for the different peptide N-terminal specificities between ERAP1 and ERAP2 and suggests that such differences extend throughout the whole peptide sequence. A noncrystallographic dimer observed may constitute a model for a proposed ERAP1-ERAP2 heterodimer. Overall, the structure helps explain how two homologous aminopeptidases cooperate to process a large variety of sequences, a key property of their biological role. The Crystal Structure of Human Endoplasmic Reticulum Aminopeptidase 2 Reveals the Atomic Basis for Distinct Roles in Antigen Processing.,Birtley JR, Saridakis E, Stratikos E, Mavridis IM Biochemistry. 2011 Dec 9. PMID:22106953[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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