6rqx
From Proteopedia
High-resolution crystal structure of ERAP1 in complex with 10mer phosphinic peptide
Structural highlights
FunctionERAP1_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. Strongly prefers substrates 9-16 residues long. Rapidly degrades 13-mer to a 9-mer and then stops. Preferentially hydrolyzes the residue Leu and peptides with a hydrophobic C-terminus, while it has weak activity toward peptides with charged C-terminus. May play a role in the inactivation of peptide hormones. May be involved in the regulation of blood pressure through the inactivation of angiotensin II and/or the generation of bradykinin in the kidney.[1] [2] [3] Publication Abstract from PubMedEndoplasmic reticulum aminopeptidase 1 (ERAP1) is an intracellular enzyme that optimizes the peptide cargo of major histocompatibility class I (MHC-I) molecules and regulates adaptive immunity. It has unusual substrate selectivity for length and sequence, resulting in poorly understood effects on the cellular immunopeptidome. To understand substrate selection by ERAP1, we solved 2 crystal structures of the enzyme with bound transition-state pseudopeptide analogs at 1.68 A and 1.72 A. Both peptides have their N terminus bound at the active site and extend away along a large internal cavity, interacting with shallow pockets that can influence selectivity. The longer peptide is disordered through the central region of the cavity and has its C terminus bound in an allosteric pocket of domain IV that features a carboxypeptidase-like structural motif. These structures, along with enzymatic and computational analyses, explain how ERAP1 can select peptides based on length while retaining the broad sequence-specificity necessary for its biological function. Mechanism for antigenic peptide selection by endoplasmic reticulum aminopeptidase 1.,Giastas P, Mpakali A, Papakyriakou A, Lelis A, Kokkala P, Neu M, Rowland P, Liddle J, Georgiadis D, Stratikos E Proc Natl Acad Sci U S A. 2019 Dec 16. pii: 1912070116. doi:, 10.1073/pnas.1912070116. PMID:31843903[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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