title: Analysis of outer membrane porin complexes of Neisseria meningitidis in wild-type and specific knock-out mutant strains.
abstract: The structure of the porin complexes of Neisseria meningitidis was assessed in the vaccine strain H44/76 and its homologous mutants lacking the main porins (PorA and PorB) and other outer membrane (OM) components (RmpM and FetA). The analysis using 1-D blue native (BN) electrophoresis, 2-D BN/SDS-PAGE and 2-D diagonal electrophoresis, followed by LC/MS-MS (for 1-D gels) or MALDI-TOF (for 2-D gels) revealed at least six porin complexes in the wild-type strain with molecular masses (MW) ranging from 145 to 195 kDa and variable composition: The two higher MW complexes are formed by PorA, PorB and RmpM, the following three are formed by PorA and PorB, and the lower MW one is formed by only PorB. Complexes in the mutants lacking either PorA, PorB or RmpM, but not those in the mutant lacking FetA, were alterered respect to those in the wild-type strain. The most evident alteration was seen in the mutant lacking PorB, in which PorA formed only a high MW complex (approximately 800 kDa). Our results suggest that PorA and PorB could form a 'basic' template for the transportation systems in the OM of the meningococci. Other proteins (such as RmpM) could be transiently associated to the porin complexes, depending on the specific tranport needs at different stages of the meningococcal life cycle, resulting in a dynamic net of pores of variable composition.
authors.affiliation: Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Marzoa
authors.forename: Ana
authors.initials: A
authors.lastname: Abel
authors.forename: Sandra
authors.initials: S
authors.lastname: Sánchez
authors.forename: Hannah
authors.initials: H
authors.lastname: Chan
authors.forename: Ian
authors.initials: I
authors.lastname: Feavers
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Criado
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Ferreirós
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000032:analysis*; D002853:Chromatography, Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D009345:Neisseria meningitidis / Q000378:metabolism*; D018272:Porins / Q000032:analysis*; D053719:Tandem Mass Spectrometry
chemical_list: D001425:Bacterial Outer Membrane Proteins; D018272:Porins