Kinetic intermediates in the reactions between peptides and proteins of major histocompatibility complex class II.

AUTOR(ES)

Beeson, C

RESUMO

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.

Documentos Relacionados

• High-affinity reactions between antigen-specific T-cell receptors and peptides associated with allogeneic and syngeneic major histocompatibility complex class I proteins.
• Reactions of the subunits of the class II major histocompatibility complex molecule IAd.
• Identification of two distinct properties of class II major histocompatibility complex-associated peptides.
• Subtle conformational changes induced in major histocompatibility complex class II molecules by binding peptides
• The invariant chain forms complexes with class II major histocompatibility complex molecules and antigenic peptides "in vivo".