Figure 6.

Determination of the amount of oxidized rA11 heavy-chain monomer that refolds properly into the matured state with a quantitative and conformationally sensitive ELISA. The double log plot shows the amount of heavy-chain monomer offered to the folding reaction that was detected in the fully matured MHC-I complex. A non-reducing SDS-PAGE analysis of the purified rA11 sample is shown in the insert. Graded concentrations of denatured rA11 were diluted in a 100 mM Tris-maleate (pH 6.6) refolding buffer containing an excess of human β₂m (3 μM) and a specific peptide (10,000 nM). Detection of properly folded complexes and conversion of measured O.D.₄₅₀ values to picomolar complex was performed as described in Materials and methods. Lane 1, rA11 sample; lane 2, protein marker. Positions of rA11 isomers 1 and 3 are shown with arrows. Standard deviations of triplicate measurements are indicated on the figure.