First cells reprogrammed to make synthetic polymers – and virus-resistant drug manufacturers

Scientists have developed the first cells that can construct artificial polymers from building blocks that are not found in nature, by following instructions the researchers encoded in their genes.

The study, led by scientists from the Medical Research Council (MRC) Laboratory of Molecular Biology, in Cambridge, UK, also found the synthetic genome made the bacteria entirely resistant to infection by viruses.

The scientists say their research could lead to the development of new polymers – large molecules made of many repeating units, such as proteins, plastics, and many drugs including antibiotics – and make it easier to manufacture drugs reliably using bacteria.

They engineered the bacteria to produce tRNAs coupled with artificial monomers, which recognized the newly available codons (TCG and TAG).

They inserted genetic sequences with strings of TCG and TAG codons into the bacteria's DNA. These were read by the altered tRNAs, which assembled chains of synthetic monomers in the sequence defined by the sequence of codons in the DNA.

The researchers were able to create polymers made of up to eight monomers strung together. They joined the ends of these polymers together to make macrocycles – a type of molecule that form the basis of some drugs, such as certain antibiotics and cancer drugs.