title: Molecular analysis of VCA1008: a putative phosphoporin of Vibrio cholerae.
abstract: The PhoB/PhoR-dependent response to inorganic phosphate (Pi)-starvation in Vibrio cholerae O1 includes the expression of vc0719 for the response regulator PhoB, vca0033 for an alkaline phosphatase and vca1008 for an outer membrane protein (OMP). Sequences with high identity to these genes have been found in the genome of clinical and environmental strains, suggesting that the Pi-starvation response in V. cholerae is well conserved. VCA1008, an uncharacterized OMP involved in V. cholerae pathogenicity, presents sequence similarity to porins of Gram-negative bacteria such as phosphoporin PhoE from Escherichia coli. A three-dimensional model shows that VCA1008 is a 16-stranded pore-forming beta-barrel protein that shares three of the four conserved lysine residues responsible for PhoE anionic specificity with PhoE. VCA1008 beta-barrel apparently forms trimers that collapse into monomers by heating. Properties such as heat modifiability and resistance to denaturation by sodium dodecyl sulfate at lower temperatures permitted us to suggest that VCA1008 is a classical porin, more precisely, a phosphoporin due to its Pi starvation-induced PhoB-dependent expression, demonstrated by electrophoretic mobility shift assay and promoter fusion-lacZ assays.
authors: Unidade Multidisciplinar de Genômica, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Carolina L
authors: CL
authors: Goulart
authors: Letícia M S
authors: LM
authors: Lery
authors: Michelle M P
authors: MM
authors: Diniz
authors: João L
authors: JL
authors: Vianez-Junior
authors: Ana Gisele C
authors: AG
authors: Neves-Ferreira
authors: Jonas
authors: J
authors: Perales
authors: Paulo M
authors: PM
authors: Bisch
authors: Wanda M A
authors: WM
authors: von Krüger
mesh_terms: D000595:Amino Acid Sequence; D019677:Artificial Gene Fusion; D001426:Bacterial Proteins / Q000378:metabolism; D004269:DNA, Bacterial / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D006358:Hot Temperature; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010710:Phosphates / Q000378:metabolism; D018272:Porins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D041241:Vibrio cholerae O1 / Q000235:genetics* / Q000378:metabolism*; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D010710:Phosphates; D018272:Porins; C061278:PhoB protein, Bacteria; D001616:beta-Galactosidase