Voltage gating of conductance in lipid bilayers induced by porin from outer membrane of Neisseria gonorrhoeae.

Mauro, Alexander; Blake, M. S.; Labarca, Pedro

doi:10.1073/pnas.85.4.1071

Cited by 61 publications

(51 citation statements)

References 27 publications

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“…This fits with the strong anion selectivity of the Omp34 porin from A. delafieldii (103). Also, the anion selectivity was already noted in one of the first papers describing the N. gonorrhoeae porin (408). The porin of B. pertussis also produces an anion-selective channel (22).…”

Section: Other Porinssupporting

confidence: 56%

Molecular Basis of Bacterial Outer Membrane Permeability Revisited

Nikaido

2003

Microbiol Mol Biol Rev

3,840

3,800

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Gram-negative bacteria characteristically are surrounded by an additional membrane layer, the outer membrane. Although outer membrane components often play important roles in the interaction of symbiotic or pathogenic bacteria with their host organisms, the major role of this membrane must usually be to serve as a permeability barrier to prevent the entry of noxious compounds and at the same time to allow the influx of nutrient molecules. This review summarizes the development in the field since our previous review (H. Nikaido and M. Vaara, Microbiol. Rev. 49:1-32, 1985) was published. With the discovery of protein channels, structural knowledge enables us to understand in molecular detail how porins, specific channels, TonB-linked receptors, and other proteins function. We are now beginning to see how the export of large proteins occurs across the outer membrane. With our knowledge of the lipopolysaccharide-phospholipid asymmetric bilayer of the outer membrane, we are finally beginning to understand how this bilayer can retard the entry of lipophilic compounds, owing to our increasing knowledge about the chemistry of lipopolysaccharide from diverse organisms and the way in which lipopolysaccharide structure is modified by environmental conditions

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Section: Other Porinssupporting

confidence: 56%

Molecular Basis of Bacterial Outer Membrane Permeability Revisited

Nikaido

2003

Microbiol Mol Biol Rev

3,840

3,800

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“…There is much preliminary evidence that neisserial porins can directly interact with artificial planar lipid bilayers (41) and eukaryotic cell membranes (30,31) and form aqueous transmembrane channels for the transport of solutes and macromolecules across the outer membrane. In addition, they can form voltage-gated pores at low membrane potential (32,33). These pores are regulated by ATP and GTP with a gating mechanism that modulates the pore size and ion selectivity (similar to mitochondrial VDAC) (34), when they insert in mammalian cells, potentially contributing to the pathogenicity of the microorganism (35).…”

Section: Discussionmentioning

confidence: 99%

Neisseria meningitidisporin PorB interacts with mitochondria and protects cells from apoptosis

Massi

Ho²,

Wetzler³

2000

Proc. Natl. Acad. Sci. U.S.A.

155

141

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Neisserial porins are strong immune adjuvants and B cell activators. The effect of neisserial porin PorB on activation-induced cell death was investigated, as a potential additional mechanism of the porin's immunopotentiating ability. Neisserial porins interact with target cells to localize intracellularly in the mitochondrial compartment without negatively affecting cellular survival. Pretreatment with Neisseria meningitidis PorB porin decreased or abrogated the mitochondrial damage induced by apoptotic stimuli. In addition, end stage determinants of apoptosis, including DNA breakdown, were diminished by PorB. Immunoprecipitation experiments revealed that PorB interacts with the mitochondrial porin VDAC (voltage-dependent anion channel). The mechanism of the antiapoptotic effect of neisserial porins could be explained by the proteinprotein interaction of PorB with VDAC, similar to the interaction of VDAC with antiapoptotic Bcl-2 proteins, resulting in an enhancement of cell survival and continued activation of B cells.cell death ͉ voltage-dependent anion channel (VDAC) ͉ membrane potential ͉ staurosporine N eisserial porins, meningococcal PorA (class 1 protein) or PorB (class 2 or 3 proteins) or gonococcal protein IA or protein IB, are the major outer membrane protein of the pathogenic Neisseriaceae (1). They act as pores and are essential for organism survival. Interestingly, we and other investigators have demonstrated that these proteins act as immune stimulants and adjuvants (2-4) and can induce a T cell-dependent immune response against cell independent antigens (5-8). The mechanism of the adjuvant activity of neisserial porins recently has been elucidated, correlating with the porins' ability to upregulate the expression of the costimulatory molecule, B7-2, on the surface of B cells (and possibly other antigen-presenting cells) (6,8). Moreover, neisserial porins are potent B cell mitogens and act synergistically with CD40 or B cell receptor ligation to induce B cell proliferation and Ig secretion (6, 9). † Stimulation of immune cells normally increases their susceptibility to activation-induced cell death or apoptosis (10). Neisserial porins activate B cells as a probable mechanism of their adjuvant activity. If the porins also increased the susceptibility of B cells to apoptosis, this obviously would attenuate their immunopotentiating ability. Therefore, we investigated the ability of neisserial porins to affect the susceptibility of various cell types to apoptosis to determine whether another mechanism of the porins' adjuvant activity is to prevent B cell (and͞or antigen-presenting cell) apoptosis.If neisserial porins decreased the susceptibility of immune cells to apoptosis, what could be the possible mechanisms? It has been demonstrated that mitochondria and mitochondrial factors are intimately connected to the process of apoptosis (11). The mechanism of action of certain apoptotic stimuli, such as Fas receptor ligation or drugs like staurosporine (STS), involves opening of the mitochondrial permeabil...

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“…Biological Activities of Native and Rclass 2 Protein-The functionality of porins may be assessed by several techniques including measurements of conductivity and liposome swelling (1,2,9,29). Studies conducted by Frasch and Mocca (4) originally postulated that class 2 protein resembled bacterial porins on the basis of electrophoretic properties similar to E. coli protein I (5).…”

Section: Discussionmentioning

confidence: 99%

Structural and Functional Characterization of a Recombinant PorB Class 2 Protein from Neisseria meningitidis

Minetti¹,

Tai²,

Blake³

et al. 1997

Journal of Biological Chemistry

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An outer membrane PorB class 2 protein from Neisseria meningitidis has been overexpressed in Escherichia coli, isolated from inclusion bodies, and refolded in the presence of zwitterionic detergent. The purified recombinant and native (strain M986) counterpart exhibit most of the typical functional and structural properties that are characteristic of bacterial porins. Channel forming activity has been monitored by incorporating class 2 into reconstituted liposomes and measuring the permeation rates of various oligosaccharides through the proteoliposomes to derive a pore diameter of ϳ1.6 nm. Structural studies employing a combination of spectroscopic and electrophoretic techniques reveal that recombinant and native class 2 are identical in terms of overall conformational stability. Both proteins form stable trimers in zwitterionic detergent and retain significant secondary and tertiary structure in the presence of SDS. The thermal unfolding of zwittergen-solubilized class 2 trimers (T m ‫؍‬ 88°C) is reversible and characterized by solvent exposure of aromatic residues with concomitant disruption of tertiary and partial loss of secondary structures. SDS-induced destabilization and irreversible unfolding of the native trimeric assembly occurs at temperatures above 60°C. Our physicochemical studies of PorB class 2 protein furnish significant insight regarding the structural and functional properties of this meningococcal outer membrane protein within the porin superfamily.Porins are integral outer membrane proteins that function as molecular sieves in Gram-negative bacteria, mediating the aqueous diffusion of solutes through the water-filled channels derived from their unique folding/assembly (1-2). Although meningococcal outer membranes may contain as many as five major proteins, much of the observed serotype specificity can be attributed to PorB class 2 and class 3 proteins, both of which are mutually exclusive within different meningococcal strains and alleles from the porB gene (3). Studies on meningococcal outer membranes (3, 4) originally suggested that class 2 protein might function as a bacterial porin on the basis of noted similarities with Escherichia coli protein I (5). The strongest argument to date regarding porin function arises from comparative studies with other neisserial strains (i.e. gonococcal) for which equivalents of class 2 and class 3 proteins have been proposed (6). Evidence regarding the porin function of protein I from Neisseria gonorrhoeae has been furnished by Douglas et al. (7) and extended through further biophysical characterization (8 -9). Meningococcal porin function has also been assessed in vivo by characterizing the relative sensitivity of native and mutant strains to hydrophilic antibiotics (10 -11). A remarkable finding that appears exclusive to pathogenic neisserial strains (including the class 2-expressing serotypes) is the spontaneous transfer of porin molecules from the outer membrane of whole cells into artificial lipid bilayers (12) as well as target cell membranes (13)(1...

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Voltage gating of conductance in lipid bilayers induced by porin from outer membrane of Neisseria gonorrhoeae.

Cited by 61 publications

References 27 publications

Molecular Basis of Bacterial Outer Membrane Permeability Revisited

Molecular Basis of Bacterial Outer Membrane Permeability Revisited

Neisseria meningitidisporin PorB interacts with mitochondria and protects cells from apoptosis

Structural and Functional Characterization of a Recombinant PorB Class 2 Protein from Neisseria meningitidis

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