2026-06-27T15:46:26Zhttps://docta.ucm.es/rest/oai/request

oai:docta.ucm.es:20.500.14352/68672023-08-26T21:19:58Zcom_20.500.14352_14col_20.500.14352_15

00925njm 22002777a 4500 dc Escudero García-Calderón, José Antonio author Nivina, Aleksandra author Kemble, Harry E author Loot, Céline author Tenaillon, Olivier author Mazel, Didier author 2020-12-15 Molecular examples of evolutionary innovation are scarce and generally involve point mutations. Innovation can occur through larger rearrangements, but here experimental data is extremely limited. Integron integrases innovated from double-strand- toward single-strand-DNA recombination through the acquisition of the I2 a-helix. To investigate how this transition was possible, we have evolved integrase IntI1 to what should correspond to an early innovation state by selecting for its ancestral activity. Using synonymous alleles to enlarge sequence space exploration, we have retrieved 13 mutations affecting both I2 and the multimerization domains of IntI1. We circumvented epistasis constraints among them using a combinatorial library that revealed their individual and collective fitness effects. We obtained up to 104 -fold increases in ancestral activity with various asymmetrical trade-offs in single-strand-DNA recombination. We show that high levels of primary and promiscuous functions could have initially coexisted following I2 acquisition, paving the way for a gradual evolution toward innovation. 2050-084X 10.7554/eLife.58061 https://hdl.handle.net/20.500.14352/6867 https://doi.org/10.7554/eLife.58061 Primary and promiscuous functions coexist during evolutionary innovation through whole protein domain acquisitions