Fig. 2.

(A) Design of self-assembling nanoparticles with Ig-binding potential. Surface representation of the 60-meric LS nanoparticle of A. aeolicus (N-terminal residues are labeled in red) and ribbon presentation of Ig-binding domain B of pA of S. aureus, including a schematic of LS, pA-LS, and pA-LS in complex with chimeric CoV S1 fused to Fc-part of human IgG1 (blue-purple). (B) Electron microscopic analysis of LS nanoparticles. Representative electron microscopic photographs of pA-LS (mean diameter of 15.21 ± 1.00) and pA-LS complexed with MERS-CoV S1-Fc (molar ratio of 1:1.2) are shown. (Scale bar, 50 nm.) (C) Schematic representation of the MERS-CoV spike protein sequence (drawn to scale). S1 and S2 subunits of the 1,353-aa-long MERS-CoV spike protein are indicated, as well as the four domains (A–D) within S1 and their respective boundaries: A (blue), B (green), C (yellow), and D (orange). The positions of the transmembrane domain (black bar; predicted by the TMHMM server) and of the predicted N-glycosylation sites (Ψ; predicted by the NetNGlyc server) are indicated.