Extended Data Fig. 7: Structural Models of CARs.

Top row: schematic representations of Hu19-CD828Z (left) and FMC63-28Z (right) CAR models are shown; scFv in blue; hinge in green; transmembrane domain in yellow; intracellular domain in red. The membrane position during molecular dynamics simulations is shown in grey. Bottom row: conformational flexibility for each corresponding CAR depicted as superimposed carbon-alpha traces for a set of 50 representative conformations observed during a 50 nanosecond molecular dynamics trajectory. The differences in flexibility originate in the very different structure and dynamic behavior of the corresponding hinge regions during the dynamics simulations. Transmembrane and scFv domains are affected by the hinge properties and display very different behaviors as well. A quantitative analysis of the molecular dynamics trajectories reveals that these behaviors affect the scFv mobility (assessed as molecular diffusibility) and the proper formation of a transmembrane dimer evaluated by the helix-helix occluded surface. All models assume a dimeric structure anchored by disulfide bonds. In short, Hu19-CD828Z exhibited less conformational flexibility than FMC63-28Z.