A newly released three-dimensional model of SARS-CoV-2, the novel coronavirus responsible for the severe respiratory disease Covid-19, shows the widespread virus in atomic detail.
Experts say the models are as “accurate as they can be” given current understanding of the virus. To create the “striking” images, molecular and computational biologists from the award-winning biomedical visualization studio Visual Science turned to published scientific information about the virus, beginning with its known structure and components available in the Protein Data Bank, an international database housing 3D structural data of biological molecules like viruses, as well as proteins and nucleic acids. Specialists working with the structural virology of coronaviruses were consulted to provide feedback.
"After thorough and careful analysis of the data, we reconstruct complete models of the viral proteins and their interactions using computational biology software and then assemble the whole model of the virion based on these structures and information about the virion composition and assembly", said Scientific Director Yury Stefanov, PhD, in a statement emailed to IFLScience.
Coronaviral particles are pleiomorphic, meaning their shape can vary, but have generally been described as oval or roughly spherical in shape and ranging between 50 and 150 nanometers long. Bright colors in the image show the proteins encoded by the viral genome while gray shades correspond to structures within the host’s cells that have been taken over by the virus. The image goes deeper than previous examples and shows in “stunning detail” the viral particle with its telltale crown-like (corona) spike glycoproteins embedded within the membrane. Along the surface are spike proteins used by the virus to target and fuse with the host cell, serving as the first phase of infection. The average SARS-CoV-2 particle has about 90 spike trimers. Also visible is the membrane protein, which facilitates the virus assembly and essentially holds its many parts together.
“The model reflects scientists' current understanding of the virus's architecture. It includes surface protein spikes that interact with the receptors on the surface of the human cell to get inside, lipid envelope with an integrated layer of matrix proteins, and a genome assembly, reconstructed based on the available scientific data", explained Ivan Konstantinov, CEO, and founder of Visual Science.
Scientists around the world have been quick to document the structure of the virus through images and high-resolution reconstructions. In April, Brazilian researchers from the Oswaldo Cruz Institute isolated samples and captured the first images using electron microscopy. Other images captured by the US National Institute of Allergy and Infectious Disease showed hundreds of virus particles littered on the surface of a human cell taken from a patient.
“These gorgeous images will enhance our understanding of the virus particle, and for the non-scientist will make even more palpable the virus that is infecting millions of people,” said Vincent Racaniello, PhD, Higgins Professor at the Department of Microbiology & Immunology of Columbia University, New York.