With the outbreak of COVID-19, several studies have focused on the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its properties. Public service announcements and communications to increase awareness included illustrations of the virus that typically reveal a spherical shell. These shells also contain spike proteins and other proteins that dictate the properties of the virus, including its ability to infect other organisms. Whether the presence of these proteins affects the shape of the virus and whether the shells of these viruses are perfect spheres are still unknown.
Recently, researchers from the Seminar for Statistics in Switzerland, the Massachusetts Institute of Technology in the USA, and Duke University in the USA attempted to answer the question of the SARS-CoV-2 virus shape. The group examined 590 virus photographs and obtained a diameter ratio of 1.22 for the virus, indicating a deviation from a perfect spherical geometry.
The group combined structural mechanics, microbiology, and statistics to predict the 3D shape of a coronavirus through measurements of 2D photographs. They identified 22 papers that contained high-quality photos of the coronaviruses and analyzed them by using theoretical models. They used four geometric models of increasing complexity and determined that the viruses may not be perfectly spherical; they may be ellipsoidal.
This new work holds importance in determining the structural properties of viruses. The team believes that their work is a stepping stone toward inactivating the coronavirus family by mechanical vibrations. The work also acknowledges the assumptions made in the paper, such as the orientation of the viruses relative to the plane of the microscope and the differences in sample preparation in the different images used for the analysis. Nevertheless, this work considers the effect of various proteins embedded in the membrane on the overall structure of the viral shell and contributes to fundamental studies of virus formation.
Their study titled “Reconstruction of the real 3D shape of the SARS-CoV-2 virus” was released recently in Biophysical Journal.