A molecular view of SARS-CoV-2, the novel coronavirus

How scientists make out the difference between variants of a virus

Our happy memories of school often include chemistry practicals – test tubes and Bunsen burners. Chemistry is the study of the properties of molecules. Everything living and non-living, is made of molecules. The simple chemicals that were learnt in school, such as hydrochloric acid (which has two atoms, one hydrogen; one chlorine), are dwarfed by the complexities of biological chemistry. A protein molecule can have thousands of atoms. With increasing knowledge of chemical principles, it has been possible to move from the ‘test tube’ to theoretical studies of molecules, their structure and their interactions with other molecules. Just as there are games that let you simulate the landing of an aircraft on your computer screen, one can simulate the interactions between complex biological molecules with reasonable accuracy. Whether in simulating flight, or a molecule, mathematical methods are being linked to fundamental laws of physics. After all a protein is only a linear chain of linked amino acids (of which there are 20, each made up of between 10 and 27 atoms), neatly folded into a unique shape. Amino acids vary in their charge (positive, negative, neutral) or stickiness. Some regions of the chain of amino acids are buried in the core of the molecule. Others are on the surface. Surface amino acids determine interactions between proteins - important for assembling a structure, for binding to receptors, to antibodies and so on.