title: Characterization of an immunogenic outer membrane autotransporter protein, Arp, of Bartonella henselae.
abstract: Bartonella henselae is a recently recognized pathogenic bacterium associated with cat scratch disease, bacillary angiomatosis, and bacillary peliosis. This study describes the cloning, sequencing, and characterization of an antigenic autotransporter gene from B. henselae. A cloned 6.0-kb BclI-EcoRI DNA fragment expresses a 120-kDa B. henselae protein immunoreactive with 21.2% of sera from patients positive for B. henselae immunoglobulin G antibodies by indirect immunofluorescence, with 97.3% specificity and no cross-reactivity with antibodies against various other organisms. DNA sequencing of the clone revealed one open reading frame of 4,320 bp with a deduced amino acid sequence that shows homology to the family of autotransporters. The autotransporters are a group of proteins that mediate their own export through the outer membrane and consist of a passenger region, the alpha-domain, and an outer membrane transporter region, the beta-domain. The passenger domain shows homology to a family of pertactin-like adhesion proteins and contains seven, nearly identical 48-amino-acid repeats not found in any other bacterial or Bartonella DNA sequences. The passenger alpha-domain has a calculated molecular mass of 117 kDa, and the transporter beta-domain has a calculated molecular mass of 36 kDa. The clone expresses a 120-kDa protein and a protein that migrates at approximately 38 kDa exclusively in the outer membrane protein fraction, suggesting that the 120-kDa passenger protein remains associated with the outer membrane after cleavage from the 36-kDa transporter.
authors.affiliation: Section of Clinical Immunology, Microbiology and Virology, Department of Pathology, 50 N. Medical Drive, University of Utah, Salt Lake City, UT 84132, USA. Christine.Litwin@path.utah.edu
authors.forename: Christine M
authors.initials: CM
authors.lastname: Litwin
authors.forename: Mindy L
authors.initials: ML
authors.lastname: Rawlins
authors.forename: Erica M
authors.initials: EM
authors.lastname: Swenson
mesh_terms: D000595:Amino Acid Sequence; D016917:Angiomatosis, Bacillary / Q000276:immunology; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D018416:Bartonella henselae / Q000235:genetics* / Q000276:immunology; D001483:Base Sequence; D015153:Blotting, Western; D002372:Cat-Scratch Disease / Q000276:immunology; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D017434:Protein Structure, Tertiary / Q000235:genetics; D020449:Repetitive Sequences, Amino Acid; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid