The origin of functional diversity of flavin-dependent monooxygenases

MASCOTTI ML; FRAAIJE MW

Congreso; NWO CHAINS 2021; 2021

Identifying the determinants of enzyme functionprovides crucial information to perform activity fine-tuning more efficiently. Naturehas evolved an outstanding variety of enzyme functionalities from a limitedamount of protein folds and cofactors. How was that accomplished? Evolutionarybiochemistry tackles the origin of functional diversity in proteins bycombining molecular phylogeny and protein experimental characterization. Ancestralsequence reconstruction allows inferring the sequences of extinct ancestors ofa protein family by using sequences of modern-day enzymes. Nucleotide-dependentmonooxygenases are a populated type of key enzymes for the cellular metabolism.Particularly, flavin-dependent monooxygenases are distributed among the wholetree of life exhibiting an ample arch of chemistries. Some perform heteroatomoxidations and hydroxylations while others catalyze epoxidations and oxidationsof carbonyl moieties. In this context, our work is devoted to the understandingof how such functional diversity was achieved. By an integrated approachincluding bioinformatics, molecular evolution and ancestral sequencereconstruction, we identified changes in the architecture of this proteinfamily corresponding to the displayed chemistries. The main reaction mechanismis dictated by the structural diversification of a common central fold while substratescopes are defined by sets of historical substitutions.