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An AI has designed anti-microbial (抗菌的) proteins that were then tested in real life and shown to work.

Proteins are made of chains of amino acids (氨基酸). The sequencest (序列) of those acids determine the protein’s shape and function. Ali Madani at Profluent, a biotechnology start-up in California, and his colleagues used an AI to design millions of new proteins, and then created a small sample of those to test whether they worked.

The AI, called ProGen, works in a similar way to AIs that can generate text. ProGen learned how to generate new proteins by learning the grammar of how amino acids combine to form 280 million existing proteins. Instead of choosing a topic for the AI to write about, the researchers could specify a group of similar proteins for it to focus on. In this case, they chose a group of proteins with anti-microbial activity.

The researchers programmed checks into the AI’s process, and they also tested a sample of the AI-proposed molecules in real cells. Of the 100 molecules they physically created, 66 participated in chemical reactions similar to those of natural proteins that destroy bacteria. This suggested that these new proteins could also kill bacteria.

The researchers then imaged them with X-rays. Even though their amino acid sequences were up to 30 percent different from any existing proteins, their shapes almost matched naturally occurring proteins. James Fraser at the University of California, San Francisco, who was part of the team, says it was not clear from the start that the AI could work out how to change the amino acid sequence so much and still produce the correct shape.

“A similar process could be used to create new test molecules for drug development, though they will still have to be tested in labs, which is time-consuming,” says Madani.