The Protein ‘Periodic Table’

Researchers have created a “periodic table” that enables them to organize and predict a range of possible quaternary structures for protein complexes. Understanding such structures can provide insight into protein function and evolution. A team led by Sarah A. Teichmann of the European Bioinformatics Institute and the Wellcome Trust Sanger Institute constructed the table from experimental and computational data about the assembly pathways of homomeric and heteromeric complexes (Science 2015, DOI: 10.1126/science.aaa2245). The researchers identified five types of assembly steps, which they used to elucidate all possible patterns of subunit interfaces for complexes with given stoichiometries. They organized the resulting structures into a table ordered by number of subunit repeats and the number of unique subunits in a given complex. Approximately 92% of all known protein complex structures fit into the model; the other 8% may indicate structure assignment errors, the researchers note. The table could help in the bioengineering of proteins by showing what combinations of subunits and interfaces would form a complex with a desired arrangement.