5OPI

Crystal structure of the TAPBPR-MHC I peptide editing complex

Summary for 5OPI

• Entry DOI: 10.2210/pdb5opi/pdb
• Descriptor: H-2 class I histocompatibility antigen, D-B alpha chain, Beta-2-microglobulin, TAP binding protein-like variant (3 entities in total)
• Functional Keywords: adaptive immunity, antigen processing, antigen presentation, peptide proofreading, immune system
• Biological source: Mus musculus (Mouse); More
• Cellular location: Membrane; Single-pass type I membrane protein: P01899; Secreted . Note=(Microbial infection) In the presence of M: P61769
• Total number of polymer chains: 3
• Total formula weight: 83779.87

Authors

Thomas, C.,Tampe, R. (deposition date: 2017-08-09, release date: 2017-10-18, Last modification date: 2024-11-06)

Primary citation

Thomas, C.,Tampe, R.
Structure of the TAPBPR-MHC I complex defines the mechanism of peptide loading and editing.
Science, 358:1060-1064, 2017

PubMed Abstract: Adaptive immunity is shaped by a selection of peptides presented on major histocompatibility complex class I (MHC I) molecules. The chaperones Tapasin (Tsn) and TAP-binding protein-related (TAPBPR) facilitate MHC I peptide loading and high-affinity epitope selection. Despite the pivotal role of Tsn and TAPBPR in controlling the hierarchical immune response, their catalytic mechanism remains unknown. Here, we present the x-ray structure of the TAPBPR-MHC I complex, which delineates the central step of catalysis. TAPBPR functions as peptide selector by remodeling the MHC I α2-1-helix region, stabilizing the empty binding groove, and inserting a loop into the groove that interferes with peptide binding. The complex explains how mutations in MHC I-specific chaperones cause defects in antigen processing and suggests a unifying mechanism of peptide proofreading.

PubMed: 29025996
DOI: 10.1126/science.aao6001

Experimental method

X-RAY DIFFRACTION (3.3 Å)