Issues

(Left) Ribbons diagram of the complex between a T cell receptor (TCR) Vβ domain (yellow) and the bacterial superantigen staphylococcal enterotoxin C3 (SEC3; gray). (Right) The TCR Vβ–SEC3 complex opened like a book along a horizontal axis to show the interacting surfaces between the components. The Vβ CDR loops are colored as follows: CDR1, dark blue; CDR2, red; and CDR3, light blue; Vβ HV4, green. SEC3 residues are color coded according to their relative energetic contribution to binding the TCR β chain: red, >2.5 kcal/mol (most important); yellow, 1.5–2.5 kcal/mol; green, 0.5–1.5 kcal/mol; blue, <0.5 kcal/mol (least important). See related article in this issue by Leder et al., pp. 823–833.