InterPro domain: IPR011250

This entry represents a transmembrane beta (8,10)-barrel found in outer membrane proteins such as OmpA, OmpX and NspA, and in the outer membrane enzyme PagP [ 1 ].

OmpA is multifunctional, being required for the action of colicins K and L, and for the stabilisation of mating aggregates in conjugation; it also serves as a receptor for a number of T-even like phages, and can act as a porin with low permeability that allows slow penetration of small solutes [ 2 ]. OmpX is a cation-selective channel that is regulated by osmolarity and by MarA expression [ 3 ]. NspA (Neisseria surface protein A) is an iron-activated membrane protein of unknown function [ 4 ]. The outer membrane enzyme PagP helps pathogenic bacteria to evade the host immune response catalysing palmitate transfer from a phospholipid to a glucosamine unit of lipid A [ 5 , 6 ].

1. Gene duplication of the eight-stranded beta-barrel OmpX produces a functional pore: a scenario for the evolution of transmembrane beta-barrels. J. Mol. Biol. 366, 1174-84
2. A minimal transmembrane beta-barrel platform protein studied by nuclear magnetic resonance. Biochemistry 46, 1128-40
3. Enterobacter aerogenes OmpX, a cation-selective channel mar- and osmo-regulated. FEBS Lett. 569, 27-30
4. Expression of the iron-activated nspA and secY genes in Neisseria meningitidis group B by Fur-dependent and -independent mechanisms. J. Bacteriol. 189, 663-9
5. Topology of an outer-membrane enzyme: Measuring oxygen and water contacts in solution NMR studies of PagP. J. Am. Chem. Soc. 128, 8256-64
6. A hydrocarbon ruler measures palmitate in the enzymatic acylation of endotoxin. EMBO J. 23, 2931-41