While the proteins that create life on Earth seem to vary indefinitely, there are a few parts they all have in common. Researchers say they have discovered which simple proteins were present when life on Earth first began to diversify, as described this week in a study published in PNAS.
The authors say these prehistoric proteins are smaller pieces of molecules that we know today as “enzymes” — materials that facilitate chemical reactions in living organisms. When isolated on their own, it appears the fragments act as enzymes, too. Two pieces in particular — one that binds iron to sulfur and one that helps nucleotides, the core pieces of DNA, connect — might be two of the oldest enzymes on Earth.
