Figure S6.

Conformational Change Surrounding the “Pocket” of Echo 6 Virus and Echo 6 Virus with Its Receptor FcRn, Related to Figure 4

(A) Backbone traces of atomic models showing the conformation of the “pocket” in Echo 6 full particles in pH 7.4. Backbone of Echo 6 full particles is shown in gray. The inner pocket is shown in surface model.

(B) Conformational difference of the protein surrounding the “pocket” region of Echo 6 full-particle with empty-particle at pH 7.4. The backbone of Echo 6 full particle is shown in gray, and empty particle is shown in pink. The remarkable residues involved in conformational changes are shown as sticks and colored by elements. The pocket in the empty-particle is obviously collapsed as compared to that in the full viral particle.

(C) Backbone traces of atomic models showing the conformation of the “pocket.” Backbone of Echo 6 particle in the Echo 6-FcRn complex at pH 7.4 is shown in green. The pocket is highly similar to that in the full viral particle and allows the accommodation of the “pocket factor.”

(D) The conformational difference of the Echo 6-FcRn complex at pH 7.4 and pH 5.5. Backbones of the Echo 6 particle in the Echo 6-FcRn complex at pH 7.4 and pH 5.5 are shown in green and cyan, respectively. The “pocket” in the Echo 6-FcRn complex at pH 5.5 began to shrink compared to that at pH 7.4, but is not fully collapsed as observed in the empty particle. The remarkable residues involved in the conformational change are shown as sticks and colored by elements.