Scientists incubated mouse cells with fluorescently labeled SARS-CoV-2 spike protein (green), and then used fluorescence microscopy to see human ACE2 proteins produced on the cells.
Viewed from the left, the arrow points to the cell membrane and shows a view through the center of the cells. An International collaboration of scientists from Columbia University and the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory has shown how to make huge amounts of the receptor on the surface of human cells that is bound by the COVID-19 virus, SARS-CoV-2.
The initial stage of the virus’s infection is the binding between the now-famous viral spike protein and the human “ACE2” receptor. Generating human ACE2 protein in mouse cells provides researchers with a novel approach to investigate these receptors and maybeUse them.
Furthermore, the technique may make it easier to investigate other complex proteins that have proven challenging to make through conventional methods, as detailed in an article that was just published in the journal Virology.
Early in the pandemic, the scientists at Brookhaven set out to produce vast quantities of human ACE2 and then bind the protein to nanoparticles. Subsequently, the ACE2-coated nanoparticles might be investigated as antiviral medications or as virus particle detectors.
Large amounts of fully functioning protein are required for both of these uses, according to virologist Paul Freimuth of Brookhaven Laboratories, who oversaw the study in association with researchers at the Center for Functioning Nanomaterials (CFN) at Brookhaven Laboratories.
However, producing useful membrane proteins such as ACE2is especially difficult since proteins are distributed in the cell membrane by a complicated process.” One explanation for this is that, before being inserted into the cell membrane, these proteins undergo a variety of modifications following their synthesis. Specifically, the addition of carbohydrates to proteins is critical for the folding of the lengthy protein chain into its final three-dimensional shape as well as the activity of the protein in the membrane.
Approximately one-third of the bulk of the ACE2 protein is made up of carbohydrates. The enzymes needed to attach those carbohydrate add-ons are absent from bacteria, the most basic organisms used by scientists to synthesize proteins .
The group employed the intact gene to boost the likelihood that mouse cells would absorb and read the human ACE2 gene correctly. In addition to the DNA sequence that codes for the amino acid building blocks that make up a protein, genes from humans and other “higher organisms” carry a wealth of other information.
This additional data aids in controlling the structure and function of genes within the chromosomes of the cell. The Human Genome Project, a DOE-sponsored endeavor to map out the locations of every gene that makes us human, produced libraries of cloned DNA fragments that the scientists searched until they found a fragment that contained the entire ACE2 gene, complete with its embedded regulatory information.
Next, they coated nanoparticles in this and exposed mouse cells to it.