Primary and promiscuous functions coexist during evolutionary innovation through whole protein domain acquisitions

eLife

Didier Mazel¹  Aleksandra Nivina¹  Harry E Kemble²  Céline Loot³  José Antonio Escudero⁴  Olivier Tenaillon⁴ 

[1] CNRS, UMR3525, Paris, France;Molecular Basis of Adaptation, Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain;VISAVET Health Surveillance Centre. Universidad Complutense Madrid. Avenida Puerta de Hierro, Madrid, Spain;Institut Pasteur, Unité de Plasticité du Génome Bactérien, Département Génomes et Génétique, Paris, France;

关键词: integron;    evolution;    recombination;    innovation;    integrase;    domain acquisition;   

DOI  :  10.7554/eLife.58061

来源: DOAJ

【 摘 要 】

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 α-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.

【 授权许可】

Unknown