Thermal stability comparison of purified empty and peptide-filled forms of a class I MHC molecule.
A secreted form of a class I major histocompatibility complex (MHC) molecule was denatured and renatured in vitro in the absence of peptide. The resulting empty class I heterodimer was immunologically reactive and structurally similar to a heterodimer renatured in the presence of an appropriate restricted peptide. Thermal stability profiles indicated that the two forms of heterodimer differed in their resistance to denaturation by heat but that a significant portion of the empty class I heterodimers had a native conformation at physiological temperatures. Free energies calculated from these data gave a direct measure of the stabilization of the class I MHC molecule that resulted from peptide binding.
Division of Biology, California Institute of Technology, Pasadena 91125.
M L
ML
Fahnestock
I
I
Tamir
L
L
Narhi
P J
PJ
Bjorkman
D000818:Animals; D016466:CHO Cells; D002942:Circular Dichroism; D006224:Cricetinae; D004355:Drug Stability; D004797:Enzyme-Linked Immunosorbent Assay; D005974:Glutamate-Ammonia Ligase / Q000235:genetics / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000737:chemistry* / Q000235:genetics; D006358:Hot Temperature; D006801:Humans; D046911:Macromolecular Substances; D011487:Protein Conformation; D017510:Protein Folding; D013816:Thermodynamics; D014162:Transfection
D015395:Histocompatibility Antigens Class I; D046911:Macromolecular Substances; D005974:Glutamate-Ammonia Ligase