Modeling of Piezo1 protein and location of Er antigenic sites. A homology model for the human Piezo1 sequence was generated using coordinates form PDB ID 5Z10¹⁶ and inserted into a model membrane for subsequent molecular dynamics calculations for a total trajectory time of 100 ns. (A) Top view on extracellular side of equilibrated Piezo1 trimer (composed of 3 chains: red, green, and blue). Lipids have been omitted from the illustration for simplicity. The residues encompassing the antigenic sites are shown as spheres (colored by atom type) located in and around the center of the trimer. (B) Side-view slice of the Piezo1 trimer with the transmembrane section of 1 monomer (red) removed to allow view on center. Representation is the same as in panel A. Side chains of antigenic sites (Er^a/Er^b, Er4, and Er5) are highlighted for the red monomer. (C-E) Er^a/Er^b loops as predicted by molecular dynamics calculations. The backbones of loops encompassing residues 2384 to 2408 are shown in green with the remainder of the protein trimer in beige. The conformation (in green) is representative of the highest populated cluster in the trajectory. The first row represents a side view onto the central extracellular domain, and below it is a depiction of the apical view on the membrane plane as indicated in figure panels. (C) Er^a representative loop. (D) Er^b representative loop. (E) Glu2392Lys representative loop.