Figure 9
Cryo-EM structure of CD25-BT942 Fab complex. (a) The cryo-EM map of CD25-BT942 Fab complex. CD25 is colored in yellow, and the light chain and heavy chain of BT942 Fab is shown as cyan and green density, respectively. (b) The atomic model of CD25-BT942 Fab complex. Color codes are as in (a). The left and right panels show two different views of this complex. (c) BT942 Fab and IL-2 bind with CD25 in opposite direction according to the superposition of the CD25-BT942 Fab cryo-EM structure with the IL-2 quaternary signaling complex structure (PDB: 2B5I). The color codes of CD25-BT942 Fab complex are as in (a), with IL-2Rβ and IL-2Rγ shown as a grey transparent surface. IL-2 is shown in red to highlight its orientation. The boxed area represents the interface shown in (d) and (e). (d,e) The close-up views of the interface between CD25 and BT942 Fab showing the epitopes on CD25 (grey labels) and paratopes on BT942 (green labels). The hydrogen bonds are depicted as yellow dashed lines.
