On the evolution of flavin-dependent enzymes: retracing the steps

MASCOTTI, ML; FRAAIJE, MW; JURI AYUB, M

Simposio; 19th International Symposium on Flavins and Flavoproteins; 2017

Thelimited number of protein domains and cofactors that Nature has employed to growan astounding variety of enzymatic functions, will never cease delighting us. Althoughenzymes are highly flexible molecules, they form thermodynamically stable structuresand therefore their evolutionary trajectories are constrained to a narrow rangeof pathways. Understandingthe evolutionary history of an enzyme family will reveal the complex network ofchanges that have occurred from ancestral sequences leading to the emergence ofextant enzymes. This will allow us to better comprehend enzyme mechanisms and identifythe essential subset of residues responsible of functional differences betweenfamily members. Moreover, dynamics of enzyme evolution can unveil thefunctional constraints and contingencies on how a new enzyme function arises,and ultimately what makes an enzyme to display a certain activity. In thiscontext, the evolutionary history of two different enzyme families (meaning, a setof enzymes displaying the same fold and active site features and thus likely toshare a common ancestor) was studied. Flavin-dependent monooxygenases are a functionallydiverse family, including aromatic hydroxylases, Baeyer-Villiger monooxygenasesand epoxidases. By integrating data from sequences, 3D structures, multidomainarchitectures, chemistry and phylogenetic inferences, we were able to unveil acomplex set of factors influencing the evolution of this family and leading toits current diversity1,2. By a different approach, we have focusedon resolving the evolutionary relationships of enzymes using F420 and/orFMN as cofactor. Particularly, how reductases and dehydrogenases, with a focuson FGDs (glucose-6-phosphate dehydrogenases)3, emerged from anFMN-dependent ancestor and diverged into the current functional variety, hasbeen addressed. Moreover, by using the ancestral sequence reconstructionapproach and resurrecting enzymes in the lab, the emergence of thedehydrogenase function has been traced.Theseexamples show how phylogeny and bioinformatics bridge the gap between biochemistryand molecular evolution and provide insight on how a new enzyme-function emerges.This offer valuable information for enzymology related research and mayfacilitate more effective enzyme discovering and enzyme engineering efforts.   References1Mascotti ML, Juri Ayub M, Furnham N,Thornton JM, Laskowski RA (2016) Chopping and changing: the evolution of the flavin-dependentmonooxygenases, J Mol Biol, 428(15): 3131-3146. 2Mascotti ML, Lapadula WJ, Juri Ayub M(2015) The origin and evolution of Baeyer-Villiger Monooxygenases (BVMOs): anancestral family of flavin monooxygenases, PLoS One, 10(7):e0132689.3Nguyen QT, Trinco G, Binda C, Mattevi A,Fraaije MW (2016) Discovery and characterization of an F420-dependent glucose-6-phosphatedehydrogenase (Rh-FGD1) from Rhodococcusjostii RHA1, Appl Microbiol Biotechnol, Epub ahead of print.*Corresponding author: mlmascotti@unsl.edu.ar