Unmasking the ancestral activity of integron integrases reveals a smooth evolutionary transition during functional innovation.

ABSTRACT: Tyrosine (Y)-recombinases have evolved to deliver mechanistically different reactions on a variety of substrates, but these evolutionary transitions are poorly understood. Among them, integron integrases are hybrid systems recombining single- and double-stranded DNA partners. These reactions are asymmetric and need a replicative resolution pathway, an exception to the canonical second strand exchange model of Y-recombinases. Integron integrases possess a specific domain for this specialized pathway. Here we show that despite this, integrases are still capable of efficiently operating the ancestral second strand exchange in symmetrical reactions between double-stranded substrates. During these reactions, both strands are reactive and Holliday junction resolution can follow either pathway. A

SUBMITTER: Escudero JA 

PROVIDER: S-EPMC4792948 | biostudies-literature | 2016 Mar

REPOSITORIES: biostudies-literature