Dataset Information

Identification and functional characterization of the Neisseria gonorrhoeae lbpB gene product.

ABSTRACT: We cloned lbpB, encoding a predicted 80-kDa lipoprotein, upstream of lbpA. A nonpolar mutant (LbpB- LbpA+) had normal lactoferrin (LF) binding and grew normally with LF as an iron source, whereas LbpB- LbpA- and LbpB+ LbpA- strains had reduced binding of LF and did not grow with LF as an iron source. LbpB bound LF directly in an affinity purification, suggesting that LbpB might play a still-uncharacterized role in the LF iron utilization.

SUBMITTER: Biswas GD

PROVIDER: S-EPMC96337 | biostudies-literature | 1999 Jan

REPOSITORIES: biostudies-literature

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Identification and functional characterization of the Neisseria gonorrhoeae lbpB gene product.

Biswas G D GD Anderson J E JE Chen C J CJ Cornelissen C N CN Sparling P F PF

Infection and immunity 19990101 1

We cloned lbpB, encoding a predicted 80-kDa lipoprotein, upstream of lbpA. A nonpolar mutant (LbpB- LbpA+) had normal lactoferrin (LF) binding and grew normally with LF as an iron source, whereas LbpB- LbpA- and LbpB+ LbpA- strains had reduced binding of LF and did not grow with LF as an iron source. LbpB bound LF directly in an affinity purification, suggesting that LbpB might play a still-uncharacterized role in the LF iron utilization. ...[more]

PMID: 9864256

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Project description:Many Neisseriaceae do not exhibit Dam methyltransferase activity and, instead of the dam gene, possess drg (dam replacing gene) inserted in the leuS/dam locus. The drg locus in Neisseria gonorrhoeae FA1090 has a lower GC-pairs content (40.5%) compared to the whole genome of N. gonorrhoeae FA1090 (52%). The gonococcal drg gene encodes a DNA endonuclease Drg, with GmeATC specificity. Disruption of drg or insertion of the dam gene in gonococcal genome changes the level of expression of genes as shown by transcriptome analysis. For the drg-deficient N. gonorrhoeae mutant, a total of 195 (8.94% of the total gene pool) genes exhibited an altered expression compared to the wt strain by at least 1.5 fold. In dam-expressing N. gonorrhoeae mutant, the expression of 240 genes (11% of total genes) was deregulated. Most of these deregulated genes were involved in translation, DNA repair, membrane biogenesis and energy production as shown by cluster of orthologous group analysis. In vivo, the inactivation of drg gene causes the decrease of the number of live neisserial cells and long lag phase of growth. The insertion of dam gene instead of drg locus restores cell viability. We have also shown that presence of the drg gene product is important for N. gonorrhoeae FA1090 in adhesion, including human epithelial cells, and biofilm formation. Biofilm produced by drg-deficient strain is formed by more dispersed cells, compared to this one formed by parental strain as shown by scanning electron and confocal microscopy. Also adherence assays show a significantly smaller biomass of formed biofilm (OD570 = 0.242 ± 0.038) for drg-deficient strain, compared to wild-type strain (OD570 = 0.378 ± 0.057). Dam-expressing gonococcal cells produce slightly weaker biofilm with cells embedded in an extracellular matrix. This strain has also a five times reduced ability for adhesion to human epithelial cells. In this context, the presence of Drg is more advantageous for N. gonorrhoeae biology than Dam presence.

Project description:Neisseria gonorrhoeae, the causative agent of gonorrhea, has a number of factors known to contribute to pathogenesis; however, a full understanding of these processes and their regulation has proven to be elusive. Post-translational modifications (PTMs) of bacterial proteins are now recognized as one mechanism of protein regulation. In the present study, Western blot analyses, with an anti-acetyl-lysine antibody, indicated that a large number of gonococcal proteins are post-translationally modified. Previous work has shown that N?-lysine acetylation can occur non-enzymatically with acetyl-phosphate (AcP) as the acetyl donor. In the current study, an acetate kinase mutant (1291ackA), which accumulates AcP, was generated in N. gonorrhoeae. Broth cultures of N. gonorrhoeae 1291wt and 1291ackA were grown, proteins extracted and digested, and peptides containing acetylated-lysines (K-acetyl) were affinity-enriched from both strains. Mass spectrometric analyses of these samples identified a total of 2686 unique acetylation sites. Label-free relative quantitation of the K-acetyl peptides derived from the ackA and wild-type (wt) strains demonstrated that 109 acetylation sites had an ackA/wt ratio>2 and p-values <0.05 in at least 2/3 of the biological replicates and were designated as "AckA-dependent". Regulated K-acetyl sites were found in ribosomal proteins, central metabolism proteins, iron acquisition and regulation proteins, pilus assembly and regulation proteins, and a two-component response regulator. Since AckA is part of a metabolic pathway, comparative growth studies of the ackA mutant and wt strains were performed. The mutant showed a growth defect under aerobic conditions, an inability to grow anaerobically, and a defect in biofilm maturation. In conclusion, the current study identified AckA-dependent acetylation sites in N. gonorrhoeae and determined that these sites are found in a diverse group of proteins. This work lays the foundation for future studies focusing on specific acetylation sites that may have relevance in gonococcal pathogenesis and metabolism.

Dataset Information

Identification and functional characterization of the Neisseria gonorrhoeae lbpB gene product.

Publications

Identification and functional characterization of the Neisseria gonorrhoeae lbpB gene product.

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