Cartoon and topological presentations of the overall structure of EccB1. EccB1 contains five domains: A1 and C1 are shown in green, A2 is shown in yellow and B1 and B2 are shown in green and purple, respectively. The N-terminus (predicted structure shown in grey) is likely to span the IM and is located in proximity to the C-terminus. In the topological structure, domains A1–B1–C1 are shown in green and A2–B2–C2 are shown in yellow. Loops A and B are shown in red and blue, respectively. MM, mycomembrane. IM, inner membrane.