Markus Buehler and others at the Massachusetts Institute of Technology have developed a system to convert the molecular structures of proteins, the basic building blocks of all living beings, into audible sound that resembles musical passages. The work was published in “ACS Nano”.
The system translates the 20 types of amino acids, the building blocks that join together in chains to form all proteins, into a 20-tone scale. Any protein’s long sequence of amino acids then becomes a sequence of notes. The tones and their relationships are based on the actual vibrational frequencies of each amino acid molecule itself, which are then transposed to bring them within the audible range for humans. Buehler said that after listening to the resulting melodies, he was able to distinguish certain amino acid sequences that corresponded to proteins with specific structural functions. Proteins make up the structural material of skin, bone, and muscle but are also enzymes, signalling chemicals, molecular switches, and a host of other functional materials that make up the machinery of all living things. But their structures, including the way they fold themselves into the shapes that often determine their functions, are exceedingly complicated. “We don’t know what makes a silk protein a silk protein or what patterns reflect the functions found in an enzyme. We don’t know the code,” said Buehler.
By translating that language into a form that humans are particularly well-attuned to and that allows different aspects of the information to be encoded in different dimensions—pitch, volume, and duration—Buehler and his team hope to glean new insights into the relationships and differences between different families of proteins and their variations and use this as a way of exploring the many possible tweaks and modifications of their structure and function.
The team then used an artificial intelligence system to study the catalogue of melodies produced by a wide variety of different proteins. They had the AI system introduce slight changes in the musical sequence or create completely new sequences, and then translated the sounds back into proteins that correspond to the modified or newly designed versions. With this process they were able to create variations of existing proteins, thus making new proteins unlike any produced by evolution.