title: The moonlighting protein fructose-1, 6-bisphosphate aldolase of Neisseria meningitidis: surface localization and role in host cell adhesion.
abstract: Fructose-1, 6-bisphosphate aldolases (FBA) are cytoplasmic glycolytic enzymes, which despite lacking identifiable secretion signals, have also been found localized to the surface of several bacteria where they bind host molecules and exhibit non-glycolytic functions. Neisseria meningitidis is an obligate human nasopharyngeal commensal, which has the capacity to cause life-threatening meningitis and septicemia. Recombinant native N. meningitidis FBA was purified and used in a coupled enzymic assay confirming that it has fructose bisphosphate aldolase activity. Cell fractionation experiments showed that meningococcal FBA is localized both to the cytoplasm and the outer membrane. Flow cytometry demonstrated that outer membrane-localized FBA was surface-accessible to FBA-specific antibodies. Mutational analysis and functional complementation was used to identify additional functions of FBA. An FBA-deficient mutant was not affected in its ability to grow in vitro, but showed a significant reduction in adhesion to human brain microvascular endothelial and HEp-2 cells compared to its isogenic parent and its complemented derivative. In summary, FBA is a highly conserved, surface exposed protein that is required for optimal adhesion of meningococci to human cells.
authors.affiliation: Molecular Bacteriology and Immunology Group, Institute of Infection, Immunity & Inflammation, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK.
authors.forename: Sarfraz A
authors.initials: SA
authors.lastname: Tunio
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Oldfield
authors.forename: Alan
authors.initials: A
authors.lastname: Berry
authors.forename: Dlawer A A
authors.initials: DA
authors.lastname: Ala'Aldeen
authors.forename: Karl G
authors.initials: KG
authors.lastname: Wooldridge
authors.forename: David P J
authors.initials: DP
authors.lastname: Turner
mesh_terms: D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D005634:Fructose-Bisphosphate Aldolase / Q000235:genetics / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008589:Meningococcal Infections / Q000382:microbiology; D009345:Neisseria meningitidis / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D021381:Protein Transport
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D005634:Fructose-Bisphosphate Aldolase