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Scientists Develop a New Molecule That Blocks COVID-19 Infection

The Spike protein on the surface of SARS-CoV-2 virus (marked in red) recognizes the hACE2 protein (marked in blue) that protrudes from healthy human cells in the throat and lungs. In this way, the Spike protein acts like a key that allows the virus to invade the cell and use its machinery to reproduce itself. The newly developed RNA aptamer (marked in yellow) binds the Spike protein very strongly and blocks it ability to recognize ACE2, thereby preventing further infection. Credit: Julián Valero, Aarhus University

A research team at Aarhus UniversityEstablished in Aarhus, Denmark in 1928, Aarhus University (AU) is the largest and second oldest research university in Denmark. It comprises four faculties in Arts, Science and Technology, Health, and Business and Social Sciences and has a total of 27 departments. (Danish: Aarhus Universitet.)”>Aarhus University has developed a new molecule that attaches to the surface of SARS-CoV-2Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the official name of the virus strain that causes coronavirus disease (COVID-19). Previous to this name being adopted, it was commonly referred to as the 2019 novel coronavirus (2019-nCoV), the Wuhan coronavirus, or the Wuhan virus.”>SARS-CoV-2 virus particles. This attachment prevents the virus from entering human cells and spreading the infection.

The newly developed molecule belongs to a class of compounds known as RNARibonucleic acid (RNA) is a polymeric molecule similar to DNA that is essential in various biological roles in coding, decoding, regulation and expression of genes. Both are nucleic acids, but unlike DNA, RNA is single-stranded. An RNA strand has a backbone made of alternating sugar (ribose) and phosphate groups. Attached to each sugar is one of four bases—adenine (A), uracil (U), cytosine (C), or guanine (G). Different types of RNA exist in the cell: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA).”>RNA aptamers and it is based on the same type of building blocks that are used for mRNA vaccines. This makes them much cheaper and easier to manufacture than the antibodies that are currently used to treat Covid-19 and to detect viral infection using rapid antigen tests.

An aptamer is a piece of DNADNA, or deoxyribonucleic acid, is a molecule composed of two long strands of nucleotides that coil around each other to form a double helix. It is the hereditary material in humans and almost all other organisms that carries genetic instructions for development, functioning, growth, and reproduction. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).”>DNA or RNA that folds into a 3D structure that can recognize a specific target molecule of interest. By attaching itself to the virus surface, the RNA aptamer prevents the Spike protein from serving as a key that allows the virus to enter a cell.

Hence, the RNA aptamer is not a new type of vaccine but a compound that can potentially stop the virus from spreading in the body once someone is exposed to the virus.

The efficient binding to SARS-CoV-2 virus also means that the aptamer can be used to test for covid-19 infection.

“We have started testing the new aptamer in rapid tests and we expect to be able to detect very low concentrations of the virus,” says Professor Jørgen Kjems from Aarhus University who is the main author of the article which has just been published in the prestigious journal, PNAS.

Studies in cell culture show that the aptamer works against the previous variants of coronavirus that the researchers had the opportunity to test.

“Since we submitted the article for peer review, we have continued our studies and been able to show that it also recognizes the delta variant. Now we are waiting for samples of the newly identified variant, omicron, so we can test whether the aptamer also recognizes that,” says Jørgen Kjems.

He emphasizes, that the results with the delta variant have not yet been peer reviewed and published.

Reference: “A serum-stable RNA aptamer specific for SARS-CoV-2 neutralizes viral entry” by Julián Valero, Laia Civit, Daniel M. Dupont, Denis Selnihhin, Line S. Reinert, Manja Idorn, Brett A. Israels, Aleksandra M. Bednarz, Claus Bus, Benedikt Asbach, David Peterhoff, Finn S. Pedersen, Victoria Birkedal, Ralf Wagner, Søren R. Paludan and Jørgen Kjems, 7 December 2021, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2112942118

Funding: Carlsberg Foundation, Danish National Research Foundation, EU Horizon2020 

Source: SciTechDaily