One way this could occur is through a mutation on a part of the spike protein that prevents protective antibodies from binding to it. But some may cause changes that give the new version of the virus a selective advantage by making it more transmissible or infectious. Most mutations will not be beneficial and either stop the spike protein from working or have no effect on its function. Encoded within the viral genome, the protein can mutate and changes its biochemical properties as the virus evolves. One of the most concerning features of the spike protein of SARS-CoV-2 is how it moves or changes over time during the evolution of the virus.
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The SARS-CoV-2 virus is changing over time. The spike protein is made up of different sections that perform different functions. Production of the spike inside our cells then starts the process of protective antibody and T cell production. Given how crucial the spike protein is to the virus, many antiviral vaccines or drugs are targeted to viral glycoproteins.įor SARS-CoV-2, the vaccines produced by Pfizer/BioNTech and Moderna give instructions to our immune system to make our own version of the spike protein, which happens shortly following immunization. The spike can be subdivided into distinct functional units, known as domains, which fulfill different biochemical functions of the protein, such as binding to the target cell, fusing with the membrane, and allowing the spike to sit on the viral envelope. Spike proteins like to stick together and three separate spike molecules bind to each other to form a functional "trimeric" unit. The spike protein is composed of a linear chain of 1,273 amino acids, neatly folded into a structure, which is studded with up to 23 sugar molecules. Ebola viruses have one, the influenza virus has two, and herpes simplex virus has five. The spike protein of coronaviruses is one such viral glycoprotein. In order to gain entry to the inside of the cell, enveloped viruses use proteins (or glycoproteins as they are frequently covered in slippery sugar molecules) to fuse their own membrane to that of cells' and take over the cell. Like cellular life, coronaviruses themselves are surrounded by a fatty membrane known as an envelope. Viruses must traverse this barrier to gain access to the cell. Due to the biochemical nature of fats, the outer surface is highly negatively charged and repellent. One of the major defenses cellular life has against invaders is its outer coating, which is composed of a fatty layer that holds in all the enzymes, proteins and DNA that make up a cell. Our cells have evolved to ward off such intrusions. Instead, they have to get inside cells in order to replicate, where they use the cell's own biochemical machinery to build new virus particles and spread to other cells or individuals. In the world of parasites, many bacterial or fungal pathogens can survive on their own without a host cell to infect. But what exactly is the spike protein and why is it so important? The spike protein is also the basis of current COVID-19 vaccines, which seek to generate an immune response against it.
The new mutations may alter the biochemistry of the spike and could affect how transmissible the virus is.
#Coronavirus spike protein how to#
At the end of the process, our bodies have learned how to protect against future infection."Īn FDA spokesperson told PolitiFact: "There is no scientific data to indicate that the spike protein in mRNA vaccines is toxic or that it lingers at any toxic level in the body after vaccination.The new variant carries several peculiar changes to the spike protein when compared to other closely related variants-and that's one of the reasons why it's more concerning than other, harmless changes to the virus we have observed before. The federal Centers for Disease Control and Prevention, which calls the spike protein harmless, explains: "Our immune systems recognize that the protein doesn’t belong there and begin building an immune response and making antibodies, like what happens in natural infection against COVID-19.
As with the mRNA vaccines, this leads the immune system to recognize the spike protein as foreign and make an immune response against it, he said. The Johnson & Johnson vaccine contains a modified adenovirus - not the COVID-19 virus - with a gene that induces cells to produce the spike protein, said vaccine expert Dr. The immune system then spots the unknown protein and makes antibodies to protect against the virus. Once the cell receives these instructions, it creates the protein and displays it on its surface. But the mRNA vaccines, from Moderna and Pfizer-BioNTech, contain neither the virus nor the spike protein - just the genetic instructions for the body to make the spike protein associated with the coronavirus. The actual COVID-19 virus uses the spike protein to bind to cells, causing infection.
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