The cartoon representation on the left shows the various antibodies’ Fragment variable (Fv) aligned to unbound, uncleaved EBOV GP (PDB 5JQ3). The zoomed-in panel shows a stereoview of each alignment. On the right is a molecular surface of GPCL with the footprints of each antibody highlighted by selecting all atoms within 4 Å of the Fv. (a) The position of the β17-β18 loop (green) in unbound, uncleaved GP sterically overlaps the position of ADI-15946 in the EBOV GPCL–ADI-15946 crystal structure. (b-c) The position of the β17-β18 loop also interferes with the binding of c2G4 (PDB 5KEL), and c4G7 (PDB 5KEN). (d) The CDRs of KZ52 (PDB 3CSY), however, do not clash with the β17-β18 loop, but rather may form favorable interactions with the loop in its tethered position.