Recombinant 2019-nCoV S-trimer Protein is produced by our Mammalian expression system and the target gene encoding Cys15-Gln1208 is expressed with a 6His tag at the C-terminus. Proline substitutions ( K986P, V987P), and G/S substitutions (R682G, R683S, R685S) are introduced to stabilize the trimeric prefusion state of Spike protein and remove the furin cleavage site, respectively.