title: Proteome analysis of Neisseria meningitidis serogroup A.
abstract: Neisseria meningitidis is an encapsulated Gram-negative bacterium responsible for significant morbidity and mortality worldwide. Meningococci are opportunistic pathogens, carried in the nasopharynx of approximately 10% of asymptomatic adults. Occasionally they enter the bloodstream to cause septicaemia and meningitis. Meningococci are classified into serogroups on the basis of polysaccharide capsule diversity, and serogroup A strains have caused major epidemics mainly in the developing world. Here we describe a two-dimensional gel electrophoresis protein map of the serogroup A strain Z4970, a clinical isolate classified as ancestral to several pandemic waves. To our knowledge this is the first systematically annotated proteomic map for N. meningitidis. Total protein samples from bacteria grown on GC-agar were electrophoretically separated and protein species were identified by matrix-assisted laser desorption/ionization time of flight spectrometry. We identified the products of 273 genes, covering several functional classes, including 94 proteins so far considered as hypothetical. We also describe several protein species encoded by genes reported by DNA microarray studies as being regulated in physiological conditions which are relevant to natural meningococcal pathogenicity. Since menA differs from other serogroups by having a fairly stable clonal population structure (i.e. with a low degree of variability), we envisaged comparative mapping as a useful tool for microevolution studies, in conjunction with established genotyping methods. As a proof of principle, we performed a comparative analysis on the B subunit of the meningococcal transferrin receptor, a vaccine candidate encoded by the tbpB gene, and a known marker of population diversity in meningococci. The results show that TbpB spot pattern variation observed in the maps of nine clinical isolates from diverse epidemic spreads, fits previous analyses based on allelic variations of the tbpB gene.
authors.affiliation: Dipartimento di Biologia Molecolare, Università degli Studi di Siena, Siena, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Bernardini
authors.forename: Giovanni
authors.initials: G
authors.lastname: Renzone
authors.forename: Maurizio
authors.initials: M
authors.lastname: Comanducci
authors.forename: Roberta
authors.initials: R
authors.lastname: Mini
authors.forename: Simona
authors.initials: S
authors.lastname: Arena
authors.forename: Chiara
authors.initials: C
authors.lastname: D'Ambrosio
authors.forename: Stefania
authors.initials: S
authors.lastname: Bambini
authors.forename: Lorenza
authors.initials: L
authors.lastname: Trabalzini
authors.forename: Guido
authors.initials: G
authors.lastname: Grandi
authors.forename: Paola
authors.initials: P
authors.lastname: Martelli
authors.forename: Mark
authors.initials: M
authors.lastname: Achtman
authors.forename: Andrea
authors.initials: A
authors.lastname: Scaloni
authors.forename: Giulio
authors.initials: G
authors.lastname: Ratti
authors.forename: Annalisa
authors.initials: A
authors.lastname: Santucci
mesh_terms: D000362:Agar / Q000737:chemistry; D000483:Alleles; D001426:Bacterial Proteins / Q000737:chemistry; D003720:Densitometry; D015180:Electrophoresis, Gel, Two-Dimensional; D005798:Genes, Bacterial; D014644:Genetic Variation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008589:Meningococcal Infections / Q000175:diagnosis; D009345:Neisseria meningitidis / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D020543:Proteome; D040901:Proteomics / Q000379:methods*; D013045:Species Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013223:Statistics as Topic
chemical_list: D001426:Bacterial Proteins; D020543:Proteome; D000362:Agar