Structures of MERS-CoV N-NTD complexed with potent compounds. The structures were solved using HCoV-OC43 N-NTD (PDB:4J3K) as the search model.24 Left panel: (Upper) structural superimposition of the MERS-CoV N-NTD:P1 complex (monomers 1 and 2 are in purple and pink, respectively) and the MERS-CoV N-NTD:P3 complex (monomers 1 and 2 are in brown and green, respectively) with compounds depicted as stick structures. (Lower) Interactions involving vector-fusion residues in the non-native dimer of the apoprotein shown for comparison with (A) and (B). Color is the same as in Figure 1A. Right panel: detailed interactions among MERS-CoV N-NTD and P1 (A, B) and P3 (C, D). Different Fo–Fc maps were contoured at ∼2.5 σ. (A) Detailed stereoview of interactions at the P1-binding site. The color of each monomer is the same as in the left panel. Residues constructing the P1-binding pocket are labeled and showed as sticks. (B) Schematic of P1 bound to MERS-CoV N-NTD. Hydrophobic contacts between P1 and each monomer are displayed as dashed lines. Nonbonding interactions are indicated by cyan arrows. (C) Detailed stereoview of interactions at the P3-binding site. The color of each monomer is the same as in the left panel. Residues belonging to the P3-binding pocket are labeled and shown as sticks. (D) Schematic of P3 bound to MERS-CoV N-NTD. Hydrophobic contacts between P3 and each monomer are displayed as dashed lines. Nonbonding interactions are indicated by red arrows.