Biomedical subjects

D Pawelec

Publications and source records attributed to D Pawelec.

At least 19 recordsLinked to original sources

PubMed1998

Campylobacter jejuni 72Dz/92 cjaC gene coding 28 kDa immunopositive protein, a homologue of the solute-binding components of the ABC transport system.

Screening of the Campylobacter jejuni 72Dz/92 cosmid gene bank enabled identification of the cjaC (Camp. jejuni antigen C) gene encoding a highly immunogenic protein of apparent molecular mass 28 kDa. Gene bank searches indicated significant overall homology of the cjaC gene product, mainly to the Gram-negative periplasmic solute-binding proteins of the ABC transport system which recognize polar amino acids and opines. CjaC protein contains the motif LVAC at the end of the putative 19 amino acid signal sequence, which suggests that it might be a lipoprotein. In the 5' flanking region of the cjaC gene, two potential promoter regions were observed. The cjaC gene is conserved among some isolates of three serotypes commonly isolated from humans (HL serotypes 1,4,71).

ATP-Binding Cassette Transporters↗

PubMed1997

Cloning and characterization of a Campylobacter jejuni 72Dz/92 gene encoding a 30 kDa immunopositive protein, component of the ABC transport system; expression of the gene in avirulent Salmonella typhimurium.

Three gene libraries of Campylobacter jejuni 72Dz/92 DNA were prepared using lambda gt11, pSupercos and pWSK129 cloning vectors. Screening of the libraries with Escherichia coli absorbed antiserum generated against whole C. jejuni revealed several immunoreactive clones of apparent molecular masses 19, 28, 30 and 50 kDa. The most commonly isolated clones expressed 30 kDa protein. The nucleotide sequence of the 1768 bp C. jejuni DNA yielded one complete (ORF2) and two partial open reading frames (ORF1 and ORF3). ORF2 encoded CjaA protein exhibits relevant overall homology to several prokaryotic solute binding proteins (family 3), components of the ABC transport system, while the product of the truncated ORF3 (CjaB protein) shows extensive homology to Gram-negative bacterial proteins, members of the sugar transporter family. The genetic organization of the putative cjaAB operon was studied. The cjaA gene fragment (616 bp) was amplified from three C. jejuni strains isolated from patients with acute bloody diarrhea, whereas it was not amplified from strains which caused acute diarrhea with no blood in the stools. The gene was introduced into avirulent Salmonella typhimurium vaccine strain where it is expressed at a reasonably high level.

ATP-Binding Cassette Transporters↗

PubMed1996

Complete nucleotide sequence of the Campylobacter jejuni 72Dz asd gene.

Campylobacter jejuni asd gene was sequenced. The GC content of the gene coding region is 32.7%. The codon usage is typical for a gene in a genome with low GC content. The structure of the gene regulatory sequences resembles that one used for Escherichia coli gene transcription and translation. The amino acid sequence of the Asd protein exhibits significant homology to asd gene products from other microorganisms.

Amino Acid Sequence↗

PubMed1995

Characterization of Campylobacter jejuni asd gene cloned in Escherichia coli.

asd gene of the human enteric pathogen, Campylobacter jejuni Dz72/92, has been isolated from a genomic library constructed in the expression plasmid vector pUC8-2 in Escherichia coli. The gene has been fished out by complementation of the asd gene deletion present in the genome of E. coli chi 6097. The smallest recombinant plasmid (pUWM3) able to confer Asd+ phenotype contains a 1.8 kb insert cloned into HindIII site located within the multi-cloning site of the pUC8-2 vector. The origin of the insert has been confirmed by hybridization. Several pieces of evidence indicate that the expression of the cloned house-keeping gene is driven from its own promoter, which can be recognised by E. coli RNA polymerase. The asd gene promoter has been located on 300 kb HindIII-DraI fragment of pUWM3. Recombinant plasmid pUWM3 specifies a new 38 kDa protein which we believe is the asd gene product. Overproduction of the 38 kDa protein due to the transcription originating from the vector lacZ gene promoter is toxic for the cells.

Aspartate-Semialdehyde Dehydrogenase↗

PubMed1983