title: The leucine zipper of Aeromonas salmonicida AbcA is required for the transcriptional activation of the P2 promoter of the surface-layer structural gene, vapA, in Escherichia coli.
abstract: The Aeromonas salmonicida AbcA protein is involved in the synthesis of the O-polysaccharide side-chains on the lipopolysaccharide and is also capable of enhancing the expression of the structural gene for the A-layer, vapA, when cloned into Escherichia coli. The P2 promoter of the vapA gene of A. salmonicida was cloned into a promoter probe vector and expression in E. coli was monitored. The expression of P2::lacZ was shown to be increased when abcA was provided in trans. AbcA contains an N-terminal ATP-binding domain as well as a C-terminal leucine zipper domain. Site-directed mutagenesis has been used to show that the ATP-binding domain is required for the synthesis of the O-polysaccharide side-chains, but not for the enhancement of vapA expression. Conversely, the leucine zipper is needed for the increase in vapA expression, but not for O-polysaccharide side-chain synthesis. This indicates that AbcA is a bifunctional protein that can influence the synthesis of the two principle antigenic components of the A. salmonicida cell surface.
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000255:Adenosine Triphosphate; D000333:Aeromonas / Q000235:genetics*; D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000096:biosynthesis; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000502:physiology; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics; D016350:Leucine Zippers / Q000502:physiology*; D008070:Lipopolysaccharides / Q000096:biosynthesis; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015533:Transcriptional Activation / Q000235:genetics*; D037521:Virulence Factors
chemical_list: D018528:ATP-Binding Cassette Transporters; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D002352:Carrier Proteins; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D011993:Recombinant Fusion Proteins; D037521:Virulence Factors; C081168:abcA protein, Aeromonas salmonicida; D000255:Adenosine Triphosphate