The Outer Membrane Protein PorB from Neisseria Meningitidis: from Structure to Function to Disease

Abstract

PorB is the second most prevalent outer membrane protein in Neisseria meningitidis, is required for neisserial pathogenesis and can elicit a Toll-like receptor mediated host immune response. The x-ray crystal structure of PorB has been determined to 2.3 A resolution. Structural analysis and co-crystallization studies identify three putative solute translocation pathways through the channel pore: one pathway transports anions non-selectively, one transports cations non-selectively, and one facilitates the specific uptake of sugars. During infection, PorB likely binds host mitochondrial ATP, and co-crystallization with the ATP analog AMP-PNP suggests that binding of nucleotides regulates these translocation pathways both by partial occlusion of the pore and by restricting the motion of a putative voltage gating loop. PorB is located on the surface of N. meningitidis and can be recognized by receptors of the host innate immune system. Features of PorB suggest that Toll-like receptor mediated recognition outer membrane proteins may be initiated with a non-specific electrostatic attraction.View Large Image | View Hi-Res Image | Download PowerPoint Slide