Extended Data Fig. 4: Sample cryo-EM density for JUNV and MACV GPC and comparisons with prior GP1 structures.

a,d, Examples of cryo-EM density for segments of JUNV GPC (a) and MACV GPC (d). Segments of SSP, GP1, and GP2 are shown as sticks. Zinc ions are shown as green spheres. b,e, Superposition of JUNV GP1 (b) and MACV GP1 (e) as part of the GPC cryo-EM structures and previously determined X-ray crystal structures. For JUNV, these include structures of GP1 bound to the antigen-binding fragments (Fabs) of neutralizing antibodies GD01 (PDB: 5EN2)²², eOD01 (5NUZ)²⁴, CR1-28 (5W1K)²⁰, and JUN1 (7QU2)²³. For MACV, these include structures of unliganded GP1 (PDB: 2WFO)²⁶, GP1 bound to the ectodomain of human TfR1 (PDB: 3KAS)²⁷, GP1 bound to a soluble form of the apical domain of Neotoma albigula (rodent ortholog) TfR1 (PDB: 6S9J)²¹, and GP1 bound to the Fabs of neutralizing antibodies CR1-07 (PDB: 5W1M)²⁰ and MAC1 (PDB: 7QU1)²³. N: N terminus; C: C terminus. c,f, Cryo-EM density associated with G2_SSP consistent with myristoylation. The myristoyl group (myr) was modeled in Coot and is shown here for illustrative purposes; it was not deposited in final models because it could not be modeled unambiguously. SSP residues 2–5 are shown as sticks.