TABLE 3

Enzymatic and virological characterizations of the intramolecular protease-helicase interface in CSFV NS3a

ConstructbHelicase activity (%)cATPase activityViral antigenVirus titer (log10TCID50/ml)Plaque diam (pixel)
Kmapp (μM)kcat (s−1)
WT NS380.9 ± 3.8d41.2 ± 2.84.3 ± 0.1+6.6 ± 0.352.0 ± 5.8
NS3Hel20.0 ± 3.336.7 ± 3.64.3 ± 0.1NTeNTNT
NCf4.1 ± 1.3NDgNDNTNT
TAIL_Δ251.1 ± 2.035.4 ± 3.04.7 ± 0.1NDNT
TAIL_Δ441.2 ± 3.7114.2 ± 6.44.0 ± 0.1NDNT
CEX_183.4 ± 4.436.0 ± 3.15.0 ± 0.1NDNT
CEX_263.6 ± 4.128.3 ± 3.34.8 ± 0.2NDNT
CAP_185.8 ± 1.639.4 ± 2.44.3 ± 0.1+4.6 ± 0.141.0 ± 5.5
CAP_278.5 ± 5.028.7 ± 2.94.7 ± 0.1+1.2 ± 0.434.8 ± 6.0
HB_184.0 ± 4.035.9 ± 3.54.6 ± 0.1+5.7 ± 0.240.4 ± 9.0
HB_236.8 ± 5.946.9 ± 2.53.6 ± 0.1+4.5 ± 0.238.6 ± 4.6
HB_382.0 ± 1.150.1 ± 3.24.4 ± 0.1+6.4 ± 0.150.4 ± 6.1
HB_463.9 ± 3.939.8 ± 4.14.5 ± 0.1+6.1 ± 0.346.3 ± 5.2
  • a Values are means ± SDs.

  • b The S163A mutation introduced into the protein constructs were not present in virus variants.

  • c The helicase activity is evaluated by the percentage value of the unwound release strand (R20).

  • d The WT helicase unwinding data were based on 10 measurements.

  • e NT, not tested.

  • f NC, negative control.

  • g ND, not detected.