External ID: 20130627FPNS3INTERFERECB

Protocol: Assay Overview:

The purpose of this biochemical assay is to determine the ability of compounds in a ChemBridge compound library to interfere with the fluorescence signal of a Cy5-labeled substrate oligonucliotide of the hepatitis C non-structural protein 3 helicase (NS3h). In this biochemical assay, the fluorescence of a single strand of DNA with a 5' Cy5 fluorophore (Cy5-dT15) incubated with NS3h and test compound is monitored.

Protocol Summary:

Assays were performed in 20 uL in 384-well black small-volume microplates. All assays contained 5 nM Cy5-dT15 DNA (5'- Cy5 TT TTT TTT TTT TTT T -3'), 15 nM NS3h, 25 mM MOPS, pH 7.5, 1.25 mM MgCl2, 0.0025 mg/ml BSA, 0.005% (v/v) Tween 20, and 0.025 mM DTT. Compounds dissolved in DMSO were added at final concentration of 0.1mM and a final DMSO concentration of 1% (v/v). Cy5 fluorescence was read. Interference was calculated according to the equation below.

Interference = Fc / F[-]

Where:

Fc is the fluorescence in the presence of the compound
F[-] is the average fluorescence negative controls

Any compound that exhibited an interference value greater than 0.8 or less than 1.2 was considered inactive. Any compound that exhibited an interference value greater than or equal to 1.2 was considered active (a fluorescent enhancer) in the assay and will not be pursued further. Any compound that exhibited an interference value less than or equal to 0.8 was considered active (a fluorescent quencher) in the assay and will not be pursued further.

List of Reagents:

Cy5-dT15 (Integrated DNA Technologies Inc, custom synthesized)
dT20 (Integrated DNA Technologies Inc, custom synthesized)
MOPS (Fisher Scientific, part BP308-100)
Magnesium Chloride (Fisher Scientific, part BP214-500)
384-well plates (Greiner Bio-One, black, part 784076)

Comment: The assay was performed and submitted by the Frick Lab at the University of Wisconsin-Milwaukee. The compounds tested in this assay were from a ChemBridge compound library.

External ID: 20130624FPNS3DACB

Protocol: Assay Overview:

The purpose of this biochemical assay is to determine the ability of compounds in a ChemBridge compound library to displace the hepatitis C non-structural protein 3 helicase (NS3h) from its substrate oligonucleotide. In this biochemical assay, the fluorescence polarization of a single strand of DNA with a 5' Cy5 fluorophore (Cy5-dT15) incubated with NS3h and test compound is monitored. Fluorescence polarization increases when NS3h binds the substrate. As designed, compounds that interfere with binding decrease the fluorescence polarization.

Protocol Summary:

Assays were performed in 20 uL in 384-well black small-volume microplates. All assays contained 5 nM Cy5-dT15 DNA (5'- Cy5 TT TTT TTT TTT TTT T -3'), 15 nM NS3h, 25 mM MOPS, pH 7.5, 1.25 mM MgCl2, 0.0025 mg/ml BSA, 0.005% (v/v) Tween 20, and 0.025 mM DTT. Compounds dissolved in DMSO were added at final concentration of 0.1mM and a final DMSO concentration of 1% (v/v). Cy5 fluorescence polarization was read using a G-factor calculated from a well lacking NS3h or test compounds. Percent inhibition was calculated according to the equation below.

%_Inhibition = 100 - ( ( Fc - F[+]) / (F[-] - F[+] ) ) * 100

Where:

Fc is the fluorescence polarization in the presence of the compound
F[-] is the average fluorescence polarization of no enzyme negative controls
F[+] is the average fluorescence polarization of positive controls (200 nM dT20).

Two values were calculated: (1) the average percent inhibition of all compounds tested, and (2) three times their standard deviation. The sum of these two values was used as a cutoff parameter. Any compound that exhibited greater percent inhibition than the cutoff parameter was considered active.

List of Reagents:

Cy5-dT15 (Integrated DNA Technologies Inc, custom synthesized)
dT20 (Integrated DNA Technologies Inc, custom synthesized)
MOPS (Fisher Scientific, part BP308-100)
Magnesium Chloride (Fisher Scientific, part BP214-500)
384-well plates (Greiner Bio-One, black, part 784076)

Comment: The assay was performed and submitted by the Frick Lab at the University of Wisconsin-Milwaukee. The compounds tested in this assay were from a ChemBridge Library set.