OmpA domain
In molecular biology, the OmpA domain is a conserved protein domain with a beta/alpha/beta/alpha-beta structure found in the C-terminal region of many Gram-negative bacterial outer membrane proteins, such as porin-like integral membrane proteins, small lipid-anchored proteins, and MotB proton channels. The N-terminal half of these proteins is variable although some of the proteins in this group have the OmpA-like transmembrane domain at the N terminus. OmpA from Escherichia coli is required for pathogenesis, and can interact with host receptor molecules. MotB serve two functions in E. coli, the MotA-MotB complex attaches to the cell wall via MotB to form the stator of the flagellar motor, and the MotA-MotB complex couples the flow of ions across the cell membrane to movement of the rotor.