Assembly of MHC class I molecules analyzed in vitro.
Recent evidence suggests that peptide ligands take part in the assembly of class I molecules in living cells. We now describe a simple system for studying class I assembly in vitro. Detergent extracts of the mutant cells RMA-S and .174, in which class I assembly does not occur spontaneously, will support assembly in vitro when specific peptides are added. Peptides stabilize a conformational change in the class I heavy chain and association with beta 2-microglobulin, at concentrations approximately 100-fold lower than required in "peptide feeding" experiments with whole cells. We show that peptides bind class I molecules during assembly and demonstrate that the conformational change induced in the heavy chain is influenced by the concentrations of both peptide and beta 2-microglobulin.
Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, England.
A
A
Townsend
T
T
Elliott
V
V
Cerundolo
L
L
Foster
B
B
Barber
A
A
Tse
D000595:Amino Acid Sequence; D000818:Animals; D002474:Cell-Free System; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D046911:Macromolecular Substances; D051379:Mice; D008969:Molecular Sequence Data; D010455:Peptides / Q000502:physiology; D011487:Protein Conformation; D001613:beta 2-Microglobulin / Q000378:metabolism* / Q000648:ultrastructure
D015395:Histocompatibility Antigens Class I; D046911:Macromolecular Substances; D010455:Peptides; D001613:beta 2-Microglobulin