Crystal structure of the OpcA integral membrane adhesin from
            <i>Neisseria</i>
            <i>meningitidis</i>

Prince, Stephen M.; Achtman, Mark; Derrick, Jeremy P.

doi:10.1073/pnas.062630899

Cited by 82 publications

(57 citation statements)

References 42 publications

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“…A closer examination of the environment surrounding these two Tyr residues reveals that they form part of a pocket of hydrophobic residues formed by association of Leu-66, Leu-81, Pro-82, Ile-123, Leu-171, and Ile-237 from loops 2-5 ( Fig. 4C) (34). To assign the source of the fluorescence from OpcA, Y169F and Y218F mutations were introduced into OpcA, and the fluorescence spectra of these mutated proteins were compared with wild type (Fig.…”

Section: Resultsmentioning

confidence: 99%

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Recognition of Saccharides by the OpcA, OpaD, and OpaB Outer Membrane Proteins from Neisseria meningitidis

Moore

Bailey

Benmechernene

et al. 2005

Journal of Biological Chemistry

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The adhesion of the pathogen Neisseria meningitidis to host cell surface proteoglycan, mediated by the integral outer membrane proteins OpcA and Opa, plays an important part in the processes of colonization and invasion by the bacterium. The precise specificities of the OpcA and Opa proteins are, however, unknown. Here we use a fluorescence-based binding assay to show that both proteins bind to mono-and disaccharides with high affinity. Binding of saccharides caused a quench in the intrinsic fluorescence emission of both proteins, and mutation of selected Tyr residues within the external loop regions caused a substantial decrease in fluorescence. We suggest that the intrinsic fluorescence arises from resonance energy transfer from Tyr to Trp residues in the ␤-barrel portion of the structure. OpcA bound sialic acid with a K d of 0.31 M and was shown to be specific for pyranose saccharides. The binding specificities of two different Opa proteins were compared; unlike OpcA, neither protein bound to monosaccharides, but both bound to maltose, lactose, and sialic acidcontaining oligosaccharides, with K d values in the micromolar range. OpaB had a 10-fold higher affinity for sialic acid-containing ligands than OpaD as a result of the mutation Y165V, which was shown to restore this specificity to OpaD. Finally, the OpcA-and Opa-dependent adhesion of meningococci to epithelial cells was shown to be partially inhibited by exogenously added sialic acid and maltose. The results show that OpcA and the Opa proteins can be thought of as outer membrane lectins and that simple saccharides can modulate their recognition of complex proteoglycan receptors.

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Section: Resultsmentioning

confidence: 99%

“…The crystal structure of OpcA has shown that the protein adopts a 10-stranded ␤-barrel structure, with extensive loop regions that protrude above the surface of the outer membrane (34). The five external loop regions pack together to form a deep crevice ϳ8 Å wide, 22 Å long, and 11 Å deep, which could form a binding site for saccharide ligands.…”

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confidence: 99%

Recognition of Saccharides by the OpcA, OpaD, and OpaB Outer Membrane Proteins from Neisseria meningitidis

Moore

Bailey

Benmechernene

et al. 2005

Journal of Biological Chemistry

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“…In fact, the crystal structures of OpcA (26) and NspA (35), two outer membrane proteins of meningococci inducing bactericidal antibodies, showed that they are composed of transmembrane beta barrels containing surface-exposed loops, often with variable sequences, where the bactericidal epitopes are located. In the case of GNA 1870, secondary-structure prediction analysis shows that it is a lipoprotein with a predicted globular architecture consisting of similar proportions of alpha helices and beta strands, a structure very different from those of OpcA and NspA.…”

Section: Discussionmentioning

confidence: 99%

The Region Comprising Amino Acids 100 to 255 ofNeisseria meningitidisLipoprotein GNA 1870 Elicits Bactericidal Antibodies

et al. 2005

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GNA 1870 is a novel surface-exposed lipoprotein, identified by genome analysis of Neisseria meningitidis strain MC58, which induces bactericidal antibodies. Three sequence variants of the protein were shown to be sufficient to induce bactericidal antibodies against a panel of strains representative of the diversity of serogroup B meningococci. Here, we studied the antigenic and immunogenic properties of GNA 1870, which for convenience was divided into domains A, B, and C. The immune responses of mice immunized with each of the three variants were tested using overlapping peptides scanning the entire protein length and using recombinant fragments. We found that while most of the linear epitopes are located in the A domain, the bactericidal antibodies are directed against conformational epitopes located in the BC domain. This was also confirmed by the isolation of a bactericidal murine monoclonal antibody, which failed to recognize linear peptides on the A, B, and C domains separately but recognized a conformational epitope formed only by the combination of the B and C domains. Arginine in position 204 was identified as important for binding of the monoclonal antibody. The identification of the region containing bactericidal epitopes is an important step in the design of new vaccines against meningococci.

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“…An 18-␤-strand porin has also been suggested (10,33). While ␤ barrel proteins with 8 ␤-strands, such as E. coli OmpX (29), Neisseria meningitidis NspA (28), and Comamonas acidovorans Omp21 (2), and a 10-␤-strand protein, OpcA, of N. meningitidis (19), have been suggested to serve as outer membrane anchors rather than forming pores (2,12), the proteoliposome swelling data presented here suggest that the 12 ␤-strands of P28 and OMP-1F form pores. Confirmation of the secondary structure of P28 and OMP-1F awaits crystal structure analysis.…”

Section: Discussionmentioning

confidence: 99%

Expression and Porin Activity of P28 and OMP-1F during Intracellular Ehrlichia chaffeensis Development

2008

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Ehrlichia chaffeensis, an obligatory intracellular gram-negative bacterium, must take up various nutrients and metabolic compounds because it lacks many genes involved in metabolism. Nutrient uptake by a gramnegative bacterium occurs primarily through pores or channels in the bacterial outer membrane. Here we demonstrate that isolated E. chaffeensis outer membranes have porin activities, as determined by a proteoliposome swelling assay. The activity was partially blocked by an antibody that recognizes the two most abundant outer membrane proteins, P28/OMP-19 and OMP-1F/OMP-18. Both proteins were predicted to have structural features characteristic of porins, including 12 transmembrane segments comprised of amphipathic and antiparallel ␤-strands. The sodium dodecyl sulfate stability of the two proteins was consistent with a ␤-barrel structure. Isolated native P28 and OMP-1F exhibited porin activities, with pore sizes similar to and larger than, respectively, that of OprF, which is the porin with the largest pore size known to date. E. chaffeensis experiences temperature changes during transmission by ticks. During the intracellular development of E. chaffeensis, both P28 and OMP-1F were expressed mostly in the mid-exponential growth phase at 37°C and the late-exponential growth phase at 28°C. The porin activity of proteoliposomes reconstituted with proteins from the outer membrane fractions derived from bacteria in the mid-and late-exponential growth phases at 28°C and 37°C correlated with the expression levels of P28 and OMP-1F. These results imply that P28 and OMP-1F function as porins with large pore sizes, suggesting that the differential expression of these two proteins might regulate nutrient uptake during intracellular E. chaffeensis development at both temperatures.

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Crystal structure of the OpcA integral membrane adhesin from Neisseria meningitidis

Cited by 82 publications

References 42 publications

Recognition of Saccharides by the OpcA, OpaD, and OpaB Outer Membrane Proteins from Neisseria meningitidis

Recognition of Saccharides by the OpcA, OpaD, and OpaB Outer Membrane Proteins from Neisseria meningitidis

The Region Comprising Amino Acids 100 to 255 ofNeisseria meningitidisLipoprotein GNA 1870 Elicits Bactericidal Antibodies

Expression and Porin Activity of P28 and OMP-1F during Intracellular Ehrlichia chaffeensis Development

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