Four-billion-year-old 'fossil' protein resurrected in bacteria protects them from viruses

In a proof-of-concept experiment, a 4-billion-year-old protein engineered into modern E. coli protected the bacteria from being hijacked by a bacteria-infecting virus. It was as if the E. coli had suddenly gone analogue, but the phage only knew how to hack digital. The ancient protein, an ancestral form of thioredoxin, was similar enough to its present-day analogues that it could function in E. coli but different enough that the bacteriophage couldn't use the protein to its advantage. The work,