title: VlpA of Vibrio cholerae O1: the first bacterial member of the alpha 2-microglobulin lipocalin superfamily.
abstract: We have identified a gene, vlpA, which is closely linked to the mfrA,B locus associated with mannose-fucose-resistant haemagglutination. VlpA is an outer-membrane protein which can be labelled with [3H]palmitate and whose processing is globomycin-sensitive, suggesting that it is a lipoprotein. Homology searches revealed that VlpA belongs to the group of lipocalins of the alpha 2-microglobulin superfamily which function as small hydrophobic molecule transporters, and is the first identified bacterial member of this group. Multiple copies of this gene are present in Vibrio cholerae O1 and O139 and Southern hybridization reveals a biotype-specific pattern of fragment sizes. Construction of strains capable of hyperproducing VlpA suggested that it is able to bind haemin with low affinity but this may be due to a simple hydrophobic interaction. Attempts to construct specific mutants in vlpA have been unsuccessful, presumably because of the multiple copies of vlpA genes and their linkage to the VCR element.
authors.affiliation: Microbial Pathogenesis Unit, Department of Microbiology and Immunology, University of Adelaide, Adelaide, South Australia 5005, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Barker
authors.affiliation: Microbial Pathogenesis Unit, Department of Microbiology and Immunology, University of Adelaide, Adelaide, South Australia 5005, Australia.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Manning
mesh_terms: D000510:Alpha-Globulins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics*; D001483:Base Sequence; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial / Q000235:genetics; D054834:Lipocalins; D008074:Lipoproteins / Q000032:analysis / Q000737:chemistry* / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014734:Vibrio cholerae / Q000235:genetics*
chemical_list: D000510:Alpha-Globulins; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D054834:Lipocalins; D008074:Lipoproteins; C025500:alpha(2)-microglobulin; C095894:blc protein, E coli; C072058:VlpA protein, Mycoplasma hyorhinis