Profiling of Substrate Specificity of SARS-CoV 3CLpro
Figure 3
Substrate specificity for SARS-CoV 3CLpro.
The relative activity significantly correlated with various structural properties of substituting residues. (A) At P5 position, the relative activity correlated well with the β-sheet propensity (r = 0.711, p<0.001). (B) At P4 position, significant correlation was observed for hydrophobicity (r = 0.587, p = 0.008). The correlation was improved (r = 0.942, p<0.001) when only residues with side chain volumes of <80 Å3 (Ala, Asn, Asp, Cys, Glu, Gly, Pro, Ser, Thr and Val) were included. (C) The relative activity on P3 variants were correlated with β-sheet propensity (r = 0.510, p = 0.022). Increase in the correlation (r = 0.729, p = 0.001) was found after neglecting charged residues (Arg, Asp, Glu and Lys). (D) Only variants with hydrophobic residues (Ala, Cys, Ile, Leu, Met, Phe, and Val) at P2 position were cleavable. (E) The relative activity on P1' variants with side chain volume of <50 Å3 (Ala, Cys, Gly and Ser) were higher than that on others.