Coiled-coil receptor-binding R-domain of colicin E2
E2 is a DNase which utilizes the outer membrane receptor BtuB to bind to and enter the cell. This family of proteins is E2R135 (residues 321-443) which is the part of E2 which is responsible for binding to BtuB in a coiled coil formation.
Jiyao W et al.(2023). "The conserved domain database in 2023.",