An Experimentally Tested Scenario for the Structural Evolution of Eukaryotic Cys2His2 Zinc Fingers from Eubacterial Ros Homologs

Fortuna Netti (1) , Gaetano Malgieri (1) , Sabrina Esposito (1) , Maddalena Palmieri (1) , Ilaria Baglivo (1) , Carla Isernia (1) , James G Omichinski (2) , Paolo V Pedone (1) , Nicolas Lartillot (3) , Roberto Fattorusso (1)

1 Seconda Università degli Studi di Napoli = Second University of Naples
2 UdeM - Université de Montréal
3 BPGE - Bioinformatique, phylogénie et génomique évolutive

The exact evolutionary origin of the zinc finger (ZF) domain is unknown, as it is still not clear from which organisms it was first derived. However, the unique features of the ZF domains have made it very easy for evolution to tinker with them in a number of different manners, including their combination, variation of their number by unequal crossing-over or tandem duplication and tuning of their affinity for specific DNA sequence motifs through point substitutions. Classical Cys 2 His 2 ZF domains as structurally autonomous motifs arranged in multiple copies are known only in eukaryotes. Nonetheless, a single prokaryotic Cys 2 His 2 ZF domain has been identified in the transcriptional regulator Ros from Agrobacterium tumefaciens and recently characterized. The present work focuses on the evolution of the classical ZF domains with the goal of trying to determine whether eukaryotic ZFs have evolved from the prokaryotic Ros-like proteins. Our results, based on computational and experimental data, indicate that a single insertion of three amino acids in the short loop that separates the b-sheet from the a-helix of the Ros protein is sufficient to induce a structural transition from a Ros like to an eukaryotic-ZF like structure. This observation provides evidence for a structurally plausible and parsimonious scenario of fold evolution, giving a structural basis to the hypothesis of a horizontal gene transfer (HGT) from bacteria to eukaryotes.

Mots clés: zinc finger domain; nuclear magnetic resonance; phylogenetics analysis; evolution

Domaines: Evolution [q-bio.PE]; Génomique, Transcriptomique et Protéomique [q-bio.GN]; Applications [stat.AP]; Méthodologie [stat.ME]

Fortuna Netti, Gaetano Malgieri, Sabrina Esposito, Maddalena Palmieri, Ilaria Baglivo, et al.. An Experimentally Tested Scenario for the Structural Evolution of Eukaryotic Cys2His2 Zinc Fingers from Eubacterial Ros Homologs. Molecular Biology and Evolution, 2013, 30 (7), pp.1504 - 1513. ⟨10.1093/molbev/mst068⟩. ⟨hal-03459186⟩