External ID: APP-Toga-CHIKV-nsp2-p
Protocol:
PROTOCOL TABLE (as described by Inglese J, Shamu CE and Guy RK. 2007)
SEQUENCE No. (e.g., 1, 2, 3, etc.); PARAMETER (e.g., Cells, Incubation, Reagent, etc.); VALUE; DESCRIPTION.
1; Control / Compound; 20 nL; Echo 655 acoustic dispenser, Greiner 1536-well solid bottom black plate.
2; Enzyme; 4 uL; BioRAPTR FRD liquid dispenser (Beckman Coulter).
3; Incubation; 15 min; room temperature.
4; Reagent; 4 uL; 2.5 uM Peptide 2 substrate.
5; Incubation; 1 hr; room temperature.
6; Detection; Fluorescence; WiewLux microplate reader (PerkinElmer), 525 nm excitation, 598/25 nm emission.
NOTES (numbers refer to sequence numbers above).
1. Briefly, 20 nL DMSO, positive control ZnAc (20nM final concentration), and test compounds were transferred into a 1,536-well solid bottom black plate (789176-F, Greiner One) via Echo 655 acoustic dispenser (Beckman Coulter). For primary screens, compounds were tested at 7 concentrations, 1:3 dilution points ranging from 25 uM to 34 nM. Follow-up confirmatory screens were carried out at 11 concentrations, 1:3 dilution points from 25 uM to 0.42 nM.
2. Four uL nsP2pro enzyme mix (150 nM final concentration) in 10 mM Tris-HCl pH 8.0 with 0.01% Tween 20 assay buffer was dispensed into the plate using a BioRAPTR FRD liquid dispenser (Beckman Coulter).
3. The plate was incubated at room temperature (protected from light) for 15 min
4. Four microliter of peptide 2 substrate (2.5 uM final concentration) in assay buffer was added to the plate.
5. After 1 hour, plates were immediately read on a ViewLux high-throughput CCD imager (Exposure = 10 sec, Gain = High, Speed = Slow, Binning = 2X). The above assay was also incorporated in the NCATS HTS facility41, which allowed for robotic liquid and compound dispensing, microplate handling, and fluorescence reading..
REFERENCE:
Inglese J, Shamu CE and Guy RK, Reporting data from high throughput screening of small molecule libraries, Nature Chemical Biology, 2007, 3(8): 438-441. doi.org/10.1038/nchembio0807-438.
Comment:
Disclaimer:
Although all reasonable efforts have been made to ensure the accuracy and reliability of the data, caution should be exercised when interpreting the results as artifacts are possible from nonspecific effects such as assay signal interference. The curve fitting and activity calls presented here are based on the NCATS analysis methods [1].
Compound Ranking:
1. Compounds are first classified as having full titration curves, partial modulation, partial curve (weaker actives), single point activity (at highest concentration only), or inactive. For this assay, apparent inhibitors are ranked higher than compounds that showed apparent activation.
2. For all inactive compounds, with a ratio activity curve class of 4, PUBCHEM_ACTIVITY_SCORE is 0. For all active compounds, a score range was given for each curve class type given above. Active compounds have PUBCHEM_ACTIVITY_SCORE between 40 and 100. For a ratio activity curve class = -1.1, score = 80+abs((log_ac50+4.5)*inf_activity/20). For ratio.curve_class == -1.2 && abs(ratio.max_response) > 6*10, score = 60+abs((log_ac50+4.5)*inf_activity/20). For ratio.curve_class == -2.1 || ( ratio.curve_class==-2.2 && abs(ratio.max_response) > 6*10), score = 40+abs((log_ac50+4.5)*inf_activity/20). For ratio.curve_class == -1.2 || ratio.curve_class == -2.2, score = 20+abs((log_ac50+4.5)*inf_activity/20). Inconclusive compounds, with a donor curve class other than 4, have PUBCHEM_ACTIVITY_SCORE of 10. Inconclusive compounds have PUBCHEM_ACTIVITY_SCORE between 1 and 39.
Reference:
1. Inglese J, Auld DS, Jadhav A, et al. Quantitative high-throughput screening: a titration-based approach that efficiently identifies biological activities in large chemical libraries. Proc Natl Acad Sci U S A. 2006;103(31):11473-11478.