Fig. 4.

Similar binding of murine β₂m and bovine β₂m to the α1α2 domains of the N*01801 heavy chain. (A and B) N*01801-Mβ (light blue), which was formed by the N*01801 heavy chain and murine β₂m, is superposed on molecule 1 (green) (A) and molecule 2 (brown) (B) of the N*01801 complex, which was renatured with the N*01801 heavy chain and bovine β₂m, respectively. The red circles indicate the similar conformations of residues in the interface of the murine and bovine β₂m during binding to the α1α2 domains of the bovine MHC I N*01801 heavy chain. (C) Similar conformations of key residues of β₂m in the binding to the α1α2 domains of N*01801. Residues 31 to 34 and 52 to 60 from murine β₂m are presented as blue strands and loops, and the corresponding residues 31 to 34 and 51 to 59 from bovine β₂m are shown as green (molecule 1) and yellow (molecule 2) strands and loops. The β-strands within the α1α2 domains of N*01801 (gray ribbons) remain in the same conformation, which does not affect the binding of the peptides (gray spheres). A transparent surface of the α1α2 domains of the N*01801 heavy chain in the structure of N*01801-Mβ is shown in light purple.