Kinetic intermediates in the reactions between peptides and proteins of major histocompatibility complex class II.
The kinetics of the reactions between fluorescently labeled sperm whale myoglobin-(110-121) peptide and the murine major histocompatibility complex class II protein I-Ed have been analyzed. The presence in solution of both short- and long-lived protein-peptide complexes is demonstrated by the biphasic dissociation of the myoglobin peptide from I-Ed. The formation of the long-lived terminal complex is preceded by a characteristic induction phase. It is shown that the initially formed complex of the myoglobin peptide and I-Ed is a kinetic intermediate that undergoes a unimolecular reaction to form the terminal complex. Reactions between peptides and the class II proteins thus involve an intermediate structurally distinct from the terminal complex. The terminal complex presumably has a structure that is biologically active and similar to the published class II protein-peptide crystal structure.
Beeson
C
C
Department of Chemistry, Stanford University, CA 94305.
McConnell
H M
HM
D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D000949:Histocompatibility Antigens Class II / Q000378:metabolism*; D066298:In Vitro Techniques; D051379:Mice; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry / Q000378:metabolism; D009211:Myoglobin / Q000737:chemistry / Q000276:immunology*; D010455:Peptides / Q000737:chemistry / Q000276:immunology*; D011485:Protein Binding
D000949:Histocompatibility Antigens Class II; C024138:I-E-antigen; D009211:Myoglobin; D010455:Peptides; D009113:Muramidase