Chemists discover how a single enzyme maintains a cell's pool of DNA building blocks

Cell survival depends on having a plentiful and balanced pool of the four chemical building blocks that make up DNA—the deoxyribonucleosides deoxyadenosine, deoxyguanosine, deoxycytidine, and thymidine, often abbreviated as A, G, C, and T. However, if too many of these components pile up, or if their usual ratio is disrupted, that can be deadly for the cell.