BrnA is family of antitoxins that neutralises the toxin BrnT, Pfam:PF04365. It consists of 3 alpha-helices and a C-terminal ribbon-helix-helix DNA binding domain. As in other toxin-antitoxin systems, BrnA negatively autoregulates the brnTA operon and has higher affinity for the DNA operator when complexed with BrnT. It dimerises with two molecules of its toxin BrnT [1].

1: Molecular structure and function of the novel BrnT/BrnA toxin-antitoxin system of Brucella abortus. Heaton BE, Herrou J, Blackwell AE, Wysocki VH, Crosson S; J Biol Chem. 2012;287:12098-12110. PMID:22334680