By screening a small number of mutant enzymes, the team discovered two individual single distant mutations —located more than 11 Å from the active site— that significantly improved the enzyme’s properties.
A leading biotech company had invested significant resources into improving an enzyme’s activity and specificity. After five intensive rounds of directed evolution, they had achieved an 8x increase in activity and a 12x increase in specificity. However, they had reached a plateau.
Further progress was blocked by a critical lack of information. The enzyme had no known crystal structure (bear in mind that this was long before the release of Alphafold 2), very few similar sequences were available to serve as references, and there were no appropriate templates to build a high-quality homology model. This made standard, structure-based computational design methods impossible.
To bypass the need for structural data, our team deployed a novel sequence-based machine-learning algorithm.
This approach allowed us to pinpoint the most promising mutations without ever seeing the enzyme’s 3D structure. To compare our results from the experimental ones, we started from the wild-type sequence, achieving better results with less lab effort. We performed two additional enzyme engineering rounds with this methodology to guide the search.