The TerB_N domain is found N-terminal to TerB, and TerB_C containing proteins. It has a predominantly alpha-helical structure and contains an absolutely conserved glutamate. The presence of a conserved acidic residue suggests that it might chelate metal like TerB. 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.
Jiyao W et al.(2023). "The conserved domain database in 2023.",