An "Exquisitely Designed" Enzyme that Maintains DNA Building Blocks

It's molecular machine time, and today we'll be looking at a particularly amazing one. It's essential, it's "evolutionarily ancient," and it's unique. This machine, named ribonucleotide reductase, or RNR for short, is a beauty. News from MIT explains why your life depends on this machine:

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,...