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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the COVID-19 pandemic that began in 2019. The coronavirus 3-chymotrypsin-like cysteine protease (3CLpro) controls replication and is therefore considered a major target for antiviral discovery. This study describes the evaluation of SARS-CoV-2 3CLpro inhibitors in a novel self-assembled monolayer desorption ionization mass spectrometry (SAMDI-MS) enzymatic assay. Compared with a traditional FRET readout, the label-free SAMDI-MS assay offers greater sensitivity and eliminates false positive inhibition from compound interference with the optical signal. The SAMDI-MS assay was optimized and validated with known inhibitors of coronavirus 3CLpro such as GC376 (IC = 0.060 μM), calpain inhibitors II and XII (IC ~20-25 μM). The FDA-approved drugs shikonin, disulfiram, and ebselen did not inhibit SARS-CoV-2 3CLpro activity in the SAMDI-MS assay under physiologically relevant reducing conditions. The three drugs did not directly inhibit human β-coronavirus OC-43 or SARS-CoV-2 in vitro, but instead induced cell death. In conclusion, the SAMDI-MS 3CLpro assay, combined with antiviral and cytotoxic assessment, provides a robust platform to evaluate antiviral agents directed against SARS-CoV-2.
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http://dx.doi.org/10.1016/j.antiviral.2020.104924 | DOI Listing |
Antiviral Res
April 2022
SAMDI Tech, Inc. Chicago, IL, 60616, USA. Electronic address:
The 3-chymotrypsin-like cysteine protease (3CLpro) of severe acute respiratory syndrome conoravirus 2 (SARS-CoV-2) remains a promising therapeutic target to combat COVID-19. Our group recently described a novel duplexed biochemical assay that combines self-assembled monolayers of alkanethiolates on gold with matrix assisted laser desorption ionization (MALDI) time of flight (TOF) mass spectrometry (MS) to simultaneously measure 3CLpro and human rhinovirus 3C protease activities. This study describes applying the assay for the completion of a high-throughput duplexed screen of 300,000 diverse, drug-like small molecules in 3 days.
View Article and Find Full Text PDFNat Metab
December 2021
Department of Medicine, Division of Endocrinology, Metabolism, and Molecular Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
In mammals, circadian rhythms are entrained to the light cycle and drive daily oscillations in levels of NAD, a cosubstrate of the class III histone deacetylase sirtuin 1 (SIRT1) that associates with clock transcription factors. Although NAD also participates in redox reactions, the extent to which NAD(H) couples nutrient state with circadian transcriptional cycles remains unknown. Here we show that nocturnal animals subjected to time-restricted feeding of a calorie-restricted diet (TRF-CR) only during night-time display reduced body temperature and elevated hepatic NADH during daytime.
View Article and Find Full Text PDFChemistry
February 2022
Department of Chemistry, Northwestern University, 2145 Sheridan Rd, Evanston, IL, 60208, USA.
This paper describes a method that combines a microfluidic device and self-assembled monolayers for matrix-assisted laser desorption/ionization mass spectrometry (SAMDI) mass spectrometry to calculate the cooperativity in binding of calcium ions to peptidylarginine deiminase type 2 (PAD2). This example uses only 120 μL of enzyme solution and three fluidic inputs. This microfluidic device incorporates a self-assembled monolayer that is functionalized with a peptide substrate for PAD2.
View Article and Find Full Text PDFSLAS Discov
September 2021
SAMDI Tech, Inc., Chicago, IL, USA.
Affinity selection mass spectrometry (ASMS) has emerged as a powerful high-throughput screening tool used in drug discovery to identify novel ligands against therapeutic targets. This report describes the first high-throughput screen using a novel self-assembled monolayer desorption ionization (SAMDI)-ASMS methodology to reveal ligands for the human rhinovirus 3C (HRV3C) protease. The approach combines self-assembled monolayers of alkanethiolates on gold with matrix-assisted laser desorption ionization time-of-flight (MALDI TOF) mass spectrometry (MS), a technique termed SAMDI-ASMS.
View Article and Find Full Text PDFAntiviral Res
March 2021
Aligos Therapeutics, Inc., South San Francisco, USA. Electronic address:
The 3-chymotrypsin-like cysteine protease (3CLpro) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is considered a major target for the discovery of direct antiviral agents. We previously reported the evaluation of SARS-CoV-2 3CLpro inhibitors in a novel self-assembled monolayer desorption ionization mass spectrometry (SAMDI-MS) enzymatic assay (Gurard-Levin et al., 2020).
View Article and Find Full Text PDF