Ebselen specifically inhibits the ability
of HCV helicase to bind
nucleic acids. (A) FP-based assay to monitor HCV NS3h (or Escherichia coli SSB) binding to a Cy5-labeled oligonucleotide.
(B) Ability of compounds in the NIH clinical collection to inhibit
NS3h–DNA binding. All compounds were tested at 100 μM.
Positive control assays contained primuline (triangles) or dT20 (squares).
The solid line represents the mean of all assays, and the dotted lines
three standard deviations around the mean. (C) Cy5-dT15–NS3h
(squares) or Cy5-rU15–NS3h (circles) complexes were titrated
with ebselen (n = 3, normalized mean ± SD).
(D) Cy5-dT15–SSB (squares) or Cy5-rU15–SSB (circles)
complexes were titrated with ebselen. (E) Electrophoretic mobility
shift assay (EMSA). Samples containing the Cy5-dT15 (20 nM), NS3h
(200 nM), and various concentrations of ebselen were examined on a
15% native polyacrylamide gel (lanes 3–12). Lane 1, no NS3h;
lane 2, no ebselen.