Description
ACE2 is a human cell surface receptor that has been identified as the main point of entry for SARS-CoV-2 virions, which match and bind ACE2 with their own viral Spike protein S1 subunits. This interaction is therefore a key target in COVID-19 therapeutic research, as its inhibitors may yield a protective effect by preventing SARS-CoV-2 entry into cells. For this reason, protein-protein interaction assays suitable for ACE2-Spike inhibitor screening are relevant to current research.
HTRF assays offer many advantages over other technologies:
Homogeneous add-and-read format
No wash steps
Low background
Straightforward miniaturization from 96- or 384-well microplates to high density assay formats such as 384-well low volume and 1536-well plates
Stable signal, providing flexibility in time of readout or size of assays
Assay principle
The PPI S1/ACE2 binding is mimicking the binding of the Spike S1 protein of SARS-CoV-2 to the Angiotensin Converting Enzyme 2 (ACE2) receptor found on the surface of type I and II pneumocytes, endothelial cells, and ciliated bronchial epithelial cells. This kit should help to identify drugs or antibodies which could interfere or prevent from SARS-CoV-2 infection.
Assay protocol
4 µL of the sample is added to a 384 LV volume plate. The sample could be a protein, an Ab or a potential drug. 8 µL of labeled S1 with d2 and 8µl of ACE2 labeled with cryptate are added to the same well. The plate is incubated 24h at +4°C before reding on a specific time resolved fluorescence reader.
Validation of S1/ACE2 binding kit with unlabeled S1 and ACE2 proteins
4 µL of the unlabeled S1 or ACE2 proteins were dispensed into a 384 LV volume plate. 8 µL of labeled S1 with d2 and 8µl of ACE2 labeled with cryptate were added to the same wells. The plate was incubated 24h at +4°C before reading on a special time-resolved fluorescence reader.
Validation of S1/ACE2 binding kit with neutralizing Ab control
4 µL of the neutralizing Ab were added to a 384 LV volume plate. 8 µL of S1 labeled with d2 and 8µl of ACE2 labeled with cryptate were added to the same wells. The plate was incubated 24h at +4°C before reading on a special time-resolved fluorescence reader.
