Researchers from the University of Washington’s Institute of Protein Design have created a new method to engineer protein dimers, or pairs. Working alongside molecular biologists at Ohio State, the researchers have made it possible “to design proteins so they come together exactly how you want them to,” as the paper’s lead author explains.
Before, researchers relied on DNA to engineer dimeric proteins, utilizing complementary strands to create helical proteins held together by the hydrogen bonds between base pairs. However, DNA-created proteins lack the functionality of highly active proteins like protease, while also being prone to interference during synthesis. So, longing to create these more complex protein assemblies, the researchers engineered a new way to make them.
Using a computer program called Rosetta, the researchers designed hydrogen bond networks for their desired protein complexes, creating complementary bond networks for each pair of amino acids. For this, Rosetta algorithmically determined the ideal shape of each amino acid chain, calculating the best way to balance out intermolecular forces and finding the resulting lowest energy level, the most probable state for each chain. Thus, the researchers could accurately design complementary protein structures, so the two parts would fit together exactly.
As a result, the researchers were able to create highly specific, more active protein dimers that form double helices unencumbered by DNA and do not form unwanted shapes or interfere with other proteins during synthesis.
This new method has the potential to “transform biomedical technology”, as scientists can now have much more control over protein interactions, potentially engineering bacteria to produce energy or designing protein machines to diagnose diseases, among many other tasks. As the researchers set their sights on more complicated, dynamic protein complexes, there is no telling what exciting discoveries await.