Dataset Information

Structure-function relationships of the competence lipoprotein ComL and SSB in meningococcal transformation.

ABSTRACT: Neisseria meningitidis, the meningococcus, is naturally competent for transformation throughout its growth cycle. The uptake of exogenous DNA into the meningococcus cell during transformation is a multi-step process. Beyond the requirement for type IV pilus expression for efficient transformation, little is known about the neisserial proteins involved in DNA binding, uptake and genome integration. This study aimed to identify and characterize neisserial DNA binding proteins in order to further elucidate the multi-factorial transformation machinery. The meningococcus inner membrane and soluble cell fractions were searched for DNA binding components by employing 1D and 2D gel electrophoresis approaches in combination with a solid-phase overlay assay with DNA substrates. Proteins that bound DNA were identified by MS analysis. In the membrane fraction, multiple components bound DNA, including the neisserial competence lipoprotein ComL. In the soluble fraction, the meningococcus orthologue of the single-stranded DNA binding protein SSB was predominant. The DNA binding activity of the recombinant ComL and SSB proteins purified to homogeneity was verified by electromobility shift assay, and the ComL-DNA interaction was shown to be Mg²+-dependent. In 3D models of the meningococcus ComL and SSB predicted structures, potential DNA binding sites were suggested. ComL was found to co-purify with the outer membrane, directly interacting with the secretin PilQ. The combined use of 1D/2D solid-phase overlay assays with MS analysis was a useful strategy for identifying DNA binding components. The ComL DNA binding properties and outer membrane localization suggest that this lipoprotein plays a direct role in neisserial transformation, while neisserial SSB is a DNA binding protein that contributes to the terminal part of the transformation process.

SUBMITTER: Benam AV

PROVIDER: S-EPMC3140584 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature

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Structure-function relationships of the competence lipoprotein ComL and SSB in meningococcal transformation.

Benam Afsaneh V AV Lång Emma E Alfsnes Kristian K Fleckenstein Burkhard B Rowe Alexander D AD Hovland Eirik E Ambur Ole Herman OH Frye Stephan A SA Tønjum Tone T

Microbiology (Reading, England) 20110217 Pt 5

Neisseria meningitidis, the meningococcus, is naturally competent for transformation throughout its growth cycle. The uptake of exogenous DNA into the meningococcus cell during transformation is a multi-step process. Beyond the requirement for type IV pilus expression for efficient transformation, little is known about the neisserial proteins involved in DNA binding, uptake and genome integration. This study aimed to identify and characterize neisserial DNA binding proteins in order to further e ...[more]

PMID: 21330432

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Project description:PurposeTo investigate the relationship between longitudinal changes in macular thickness measurements from OCT and changes in central visual field (VF) in patients with glaucoma with central or advanced damage at baseline.DesignLongitudinal cohort study.ParticipantsA total of 116 eyes with ≥3 years of follow-up and ≥5 macular OCT images and central 10° VF tests were selected.MethodsOCT superpixels and VF locations were matched correcting for retinal ganglion cell (RGC) displacement. Superpixel thickness and VF total deviation (TD) values, in both logarithmic and linear scales, were averaged within 3 eccentricities (3.4°, 5.6°, and 6.8°) and superior and inferior hemiretinas and hemifields. We estimated pointwise TD rates of change and rates of change at superpixels for full macular thickness (FMT), ganglion cell complex (GCC), ganglion cell inner plexiform layer (GCIPL), and ganglion cell layer (GCL). Correlation of structure-function (SF) rates of change was investigated with parametric tests. We compared the proportion of worsening and positive slopes for superpixels and VF test locations (negative vs. positive rates of change with P < 0.05) throughout the follow-up period. Permutation analyses were used to control specificity.Main outcome measuresMagnitude of correlation between structural and functional rates of change and proportion of worsening and positive slopes as a function of follow-up time.ResultsThe median (interquartile range) follow-up and number of exams were 4.2 (3.7-4.6) years and 8 (7-9), respectively. The highest correlation of change rates was observed at 3.4° and 5.6° eccentricities (r = 0.24, 0.41, 0.40, and 0.40 for FMT, GCC, GCIPL, and GCL for 3.4° eccentricity and r = 0.28, 0.32, 0.31, and 0.32 for FMT, GCC, GCIPL, and GCL for 5.6° eccentricity, respectively). Although GCC measures demonstrated the highest overall longitudinal SF correlations, the differences were not statistically significant. Significant structural worsening was more frequently detected than functional deterioration at 3- and 5-year time points (P < 0.025). Permutation analyses also confirmed this finding.ConclusionsCorrelations between central structural and functional rates of change were weak to fair in this cohort. Structural changes were detected more frequently than functional changes. Measurements of both structure and function are required for optimal detection of central progression.

Dataset Information

Structure-function relationships of the competence lipoprotein ComL and SSB in meningococcal transformation.

Publications

Structure-function relationships of the competence lipoprotein ComL and SSB in meningococcal transformation.

Similar Datasets

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