The first pictures of the coronavirus, taken just seven months ago, resembled barely discernible smudges. But scientists have since captured the virus and its structures in intimate, atomic detail, offering crucial insights into how it functions.
Less than a millionth of an inch wide, the virus is studded with proteins called spikes that attach to cells in people’s airways, allowing the virus to infiltrate. But under an electron microscope, the proteins look more like tulips than spikes, consisting of long stems topped with what looks like a three-part flower. These spikes also swivel on a three-way hinge, which may increase their odds of encountering and attaching to proteins on human cells.
As the spikes sweep around, they can also be attacked by antibodies. But they are protected by shields made of sugar. Sugar molecules, in navy below, swirl around the proteins and hide them from antibodies.
The coronavirus genome consists of 30,000 letters that hold the information for making its proteins. The genes are arrayed on a molecular strand called RNA.
After the virus enters a human cell, our ribosomes — the tiny cellular factories that pump out proteins — attach to its RNA strands and glide down them like a roller coaster car running along a track. As the ribosomes pass over the genetic letters, they build proteins with corresponding structures.
In just a few hours, an infected cell can make thousands of new virus genomes. Ribosomes read the genes and create more viral proteins, which then combine with the new genomes to make more viruses.
Already, the new pictures of SARS-CoV-2 have become essential for the fight to end the pandemic. Vaccine developers study the virus’s structure to ensure that the antibodies made by vaccines grip tightly to the virus. Drug developers are concocting molecules that disrupt the virus by slipping into nooks and crannies of proteins and jamming their machinery.
A drug molecule, in blue, blocks the tip of the coronavirus spike.Ian Haydon, Institute for Protein Design
But while the past few months have delivered a flood of data about the virus, some studies have made it clear that it will take years to fully make sense of SARS-CoV-2.Carl Zimmer . New York Times