The TerB_N domain is found N-terminal to TerB, and TerB_C containing proteins [1]. It has a predominantly alpha-helical structure and contains an absolutely conserved glutamate [1]. The presence of a conserved acidic residue suggests that it might chelate metal like TerB [1]. These proteins occur in a two-gene operon containing an AAA+ ATPase and SF-II DNA helicase suggesting a role in stress-response or phage defence [1].

1: Ter-dependent stress response systems: novel pathways related to metal sensing, production of a nucleoside-like metabolite, and DNA-processing. Anantharaman V, Iyer LM, Aravind L; Mol Biosyst. 2012;8:3142-3165. PMID:23044854