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Updated: Aug 29, 2026
One-step Negative Chromatographic Purification of Helicobacter pylori Neutrophil-activating Protein Overexpressed in Escherichia coli in Batch Mode
Published on: June 18, 2016
Molecular cloning and characterization of two Helicobacter pylori genes coding for plasminogen-binding proteins
Klas Jönsson1, Betty P Guo, Hans-Jürg Monstein
1Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Hospital, S-171 76 Stockholm, Sweden.
Abstract:
Helicobacter pylori binds a number of host cell proteins, including the plasma protein plasminogen, which is the proenzyme of the serine protease plasmin. Two H. pylori plasminogen-binding proteins have been described; however, no genes were identified. Here we report the use of a phage display library to clone two genes from the H. pylori CCUG 17874 genome that mediate binding to plasminogen. DNA sequence analysis of one of these genes revealed 96.6% homology with H. pylori 26695 HP0508. A subsequent database search revealed that the amino acid sequence of a lysine-rich C-terminal segment of HP0508 is identical to the C terminus of HP0863. Recombinant proteins expressed from HP0508 and HP0863 bound plasminogen specifically and in a lysine-dependent manner. We designate these genes pgbA and pgbB, respectively. These proteins are expressed by a variety of H. pylori strains, have surface-exposed domains, and do not inhibit plasminogen activation. These results indicate that pgbA and pgbB may allow H. pylori to coat its exterior with plasminogen, which subsequently can be activated to plasmin. The surface acquisition of protease activity may enhance the virulence of H. pylori.
Insights
Helicobacter pylori uses two newly identified genes, pgbA and pgbB, to bind host plasminogen. This binding allows the bacteria to acquire plasmin, potentially increasing its virulence.
Area of Science:
- Microbiology
- Molecular Biology
- Pathogenesis
Background:
- Helicobacter pylori interacts with host proteins, including plasminogen, the precursor to plasmin.
- Previous studies identified plasminogen-binding proteins but not their corresponding genes in H. pylori.
Purpose of the Study:
- To identify and characterize the genes responsible for plasminogen binding in H. pylori.
- To investigate the role of these genes in bacterial virulence.
Main Methods:
- Phage display library screening to identify H. pylori genes binding to plasminogen.
- DNA sequencing and homology analysis.
- Recombinant protein expression and binding assays.
- Lysine-dependency and surface exposure analysis.
Main Results:
- Two H. pylori genes, designated pgbA and pgbB, were identified that mediate plasminogen binding.
- Recombinant PgbA and PgbB proteins specifically bound plasminogen in a lysine-dependent manner.
- These proteins are surface-exposed in various H. pylori strains and do not inhibit plasminogen activation.
Conclusions:
- PgbA and PgbB enable H. pylori to acquire plasminogen, which can be activated to plasmin on the bacterial surface.
- Surface-associated plasmin activity may contribute to H. pylori virulence.
- The identified genes provide new targets for understanding H. pylori pathogenesis.
