Extended Data Fig. 2: Illustration of splitting sites tested to generate the midi-Dys (ΔSR5–15) using split gp41.1.

Split gp41.1 with an optimized footprint (Gly-Tyr/Ser) was tested in four locations. The resulting midi-Dys (SR5–15) harbor a footprint between one to three residues. These additional residues were inserted in loops between Helix B and C of Spectrin-like repeat 19, the linker between Helix C and Hinge 3, or within Hinge 3 to minimize their impact on protein folding.