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. 2015 Oct 13;25(22):5072–5077. doi: 10.1016/j.bmcl.2015.10.023

Figure 1.

Figure 1

FIPV-3CLpro cleavage sites in polyprotein 1ab and inhibition by compounds 6 and 7. (A) The eleven polyprotein 1ab recognition sequences for FIPV-3CLpro are shown from P5 to P4′ under the blue shaded box in their respective binding locations. FIPV-3CLpro is represented by the blue shaded box where the subsites are represented as pockets and labeled accordingly. Subsites with no clear residue preferences are outlined by a dashed line, indicating they may not exist. Peptidomimetic inhibitor 6 (P4 = S) or 7 (P4 = T) binds to FIPV-3CLpro via nucleophilic attack of Cys144 at the β-carbon of the α,β-unsaturated ethyl ester, where the pyrrolidinonyl methyl acts as the P1 residue, Leu as the P2 residue, Val as the P3 residue, and either Thr or Ser as the P4 residue. (B) IC50 values for 6 and 7 against FIPV-3CLpro after both 15 and 30 min incubation periods.