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Isolation and biochemical and molecular analyses of a species-specific protein antigen from the gastric pathogen
P W O'Toole1, S M Logan, M Kostrzynska
1Department of Medical Microbiology, University of Lund, Sweden.
Abstract:
A protein of Mr 26,000 which was present in large quantities in extracts of cells of Helicobacter pylori was purified to homogeneity by ammonium sulfate precipitation followed by gel filtration and reversed-phase chromatography or anion-exchange chromatography. The protein appeared to be associated with the soluble fraction of the cell, and antibodies raised against the protein were reactive with whole-cell lysates of a variety of H. pylori strains in a simple immunodot blot assay. This reaction was species specific. Protein sequence determination of the amino terminus and internal cyanogen bromide fragments and amino acid composition analysis were performed. An oligonucleotide derived from these data was used to clone a fragment encoding most of the coding sequence. Expression in Escherichia coli was dependent on vector promoters. The DNA sequence of the fragment was determined. DNA probes derived from the cloned fragment hybridized to genomic DNA of all H. pylori strains tested, but not to DNAs of Helicobacter mustelae, Wolinella succinogenes, various Campylobacter species, and a panel of gram-negative enteric bacteria. The apparent uniqueness of this protein may be exploited for the development of species-specific diagnostics for this gastric pathogen.
Insights
Researchers identified a unique 26,000 Mr protein in Helicobacter pylori. This protein
Area of Science:
- Microbiology
- Proteomics
- Molecular Biology
Background:
- Helicobacter pylori is a significant gastric pathogen.
- Developing species-specific diagnostics for H. pylori is crucial for effective treatment and control.
Purpose of the Study:
- To isolate and characterize a unique protein from H. pylori.
- To explore the potential of this protein for developing species-specific diagnostic tools.
Main Methods:
- Protein purification using ammonium sulfate precipitation, gel filtration, and chromatography.
- Antibody generation and immunodot blot assays for species specificity.
- Amino acid sequencing, oligonucleotide-directed cloning, and DNA sequencing.
- DNA probe hybridization for genomic analysis.
Main Results:
- A 26,000 Mr protein was purified to homogeneity from H. pylori.
- Antibodies against the protein showed species-specific reactivity with H. pylori strains.
- Cloned DNA fragments hybridized exclusively to H. pylori genomic DNA, confirming species uniqueness.
- The protein and its encoding gene are specific to H. pylori.
Conclusions:
- The identified protein is unique to Helicobacter pylori.
- This unique protein holds significant potential for the development of novel, species-specific diagnostic assays for H. pylori infections.