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A High Throughput MHC II Binding Assay for Quantitative Analysis of Peptide Epitopes
07:59

A High Throughput MHC II Binding Assay for Quantitative Analysis of Peptide Epitopes

Published on: March 25, 2014

Thermal stability of MHC class I-beta 2-microglobulin peptide complexes in the endoplasmic reticulum is determined by

B A Owen1, L R Pease

  • 1Departments of Biochemistry and Molecular Biology, Mayo Clinic/Foundation, Rochester, MN 55905, USA.

Journal of Immunology (Baltimore, Md. : 1950)
|February 13, 2001
PubMed

Once MHC class I heavy chain binds beta(2)-microglobulin (beta(2)m) within the endoplasmic reticulum, an assembly complex comprising the class I heterodimer, TAP, TAPasin, calreticulin, and possibly Erp57 is formed before the binding of high affinity peptide. TAP-dependent delivery of high affinity peptide to in vitro translated K(b)beta(2)m complexes within microsomes (TAP(+)/TAPasin(+)) was studied to determine at which point peptide binding becomes resistant to thermal denaturation. It was determined that the thermal stability of K(b)-beta(2)m-peptide complexes depends on the timing of peptide binding to K(b)beta(2)m relative to TAP binding high affinity peptide. Premature exposure of the TAP complex to high affinity peptide before its association with class I heavy chain results in K(b)beta(2)m-peptide-TAP complexes that lose peptide upon exposure to elevated temperature after solubilization away from microsome-associated proteins. These findings suggest that the order in which class I heavy chain associates with endoplasmic reticulum-resident chaperones and peptide determines the stability of K(b)beta(2)m-peptide complexes.

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