title: Differential expression of porins OmpP2A and OmpP2B of Haemophilus ducreyi.
abstract: Haemophilus ducreyi is a strict human pathogen and the causative agent of the sexually transmitted disease chancroid. The genome of the human-passaged strain of H. ducreyi (35000HP) contains two homologous genes whose protein products have estimated molecular masses of 46 and 43 kDa. A comparative analysis of the deduced amino acid sequences revealed that these proteins share 27 to 33% identity to the outer membrane protein P2 (OmpP2), a major porin of Haemophilus influenzae. Therefore, these proteins have been designated OmpP2A and OmpP2B, respectively. The detection of ompP2A and ompP2B transcripts by reverse transcriptase PCR indicated that these genes were independently transcribed in H. ducreyi 35000HP. Western blot analysis of outer membrane proteins isolated from a geographically diverse collection of H. ducreyi clinical isolates revealed that OmpP2A and OmpP2B were differentially expressed among these strains. Although PCR analysis suggested that ompP2A and ompP2B were conserved among the strains tested, the differential expression observed was due to nucleotide additions and partial gene deletions. Purified OmpP2A and OmpP2B were isolated under nondenaturing conditions, and subsequent analysis demonstrated that these two proteins exhibited porin activity. OmpP2A and OmpP2B are the first porins described for H. ducreyi.
authors.affiliation: Department of Microbiology and Immunology, State University of New York at Buffalo, 14214, USA.
authors.forename: Derrick T
authors.initials: DT
authors.lastname: Prather
authors.forename: Manjeet
authors.initials: M
authors.lastname: Bains
authors.forename: Robert E W
authors.initials: RE
authors.lastname: Hancock
authors.forename: Melanie J
authors.initials: MJ
authors.lastname: Filiatrault
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Campagnari
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D015964:Gene Expression Regulation, Bacterial; D006191:Haemophilus ducreyi / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D006801:Humans; D008051:Lipid Bilayers / Q000378:metabolism; D018272:Porins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D001425:Bacterial Outer Membrane Proteins; D008051:Lipid Bilayers; C493458:OMP2A protein, Haemophilus ducreyi; C493457:OMP2B protein, Haemophilus ducreyi; C063931:Omp2 protein, bacteria; D018272:Porins; D011994:Recombinant Proteins