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Helicobacter pylori catalase (KatA) and KatA-associated protein (KapA) interaction

Sergon, Gladys Wanda (2016) MOBT01 20152
Degree Projects in Molecular Biology
Popular Abstract
Catalase transport in Helicobacter pylori

Helicobacter pylori is a bacterium that lives in the human stomach of 50% of the world’s population. Its presence in the stomach induces a strong immune response in all these cases and the body’s response to fight off the infection causes an irritation of the stomach that may be symptomatic or asymptomatic. A persistent infection may lead to ulcers or in 1-2% gastric cancer.
The immune system responds mainly by producing toxic oxygen products which the bacteria are able to withstand by producing antioxidant enzymes. One enzyme that plays a central role is catalase. It breaks down hydrogen peroxide to water and oxygen. This enzyme is usually located in the cytoplasm of the bacteria but there is... (More)
Catalase transport in Helicobacter pylori

Helicobacter pylori is a bacterium that lives in the human stomach of 50% of the world’s population. Its presence in the stomach induces a strong immune response in all these cases and the body’s response to fight off the infection causes an irritation of the stomach that may be symptomatic or asymptomatic. A persistent infection may lead to ulcers or in 1-2% gastric cancer.
The immune system responds mainly by producing toxic oxygen products which the bacteria are able to withstand by producing antioxidant enzymes. One enzyme that plays a central role is catalase. It breaks down hydrogen peroxide to water and oxygen. This enzyme is usually located in the cytoplasm of the bacteria but there is evidence showing that it may be found on the outside of the cytoplasm that is in the periplasm or on the surface of H. pylori. There is no known transport mechanism for the catalase. One theory proposes that a protein named KatA-associated protein A (KapA) shuttles catalase into the periplasm and eventually to the surface through a mode known as the hitchhiker translocation mechanism. KapA possesses a signal for the Tat bacterial transport system.
The aim of this research was to analyze interaction between catalase and KapA. Three methods of studying protein-protein interactions were used to investigate the interaction: Co-immunoprecipitation, pulldown assay and far Western blotting. These three methods showed that KapA and KatA interact. The results also showed that KatA interacts with the two forms of KapA, the full length protein, which is a stable interaction, and the cleaved form lacking the signal peptide which is consistent with the hitchhiker translocation mechanism.

An established role of KapA in KatA enzyme transport is important for the understanding of H. pylori pathogenesis.


Supervisor: Corinna Richter and Kristian Riesbeck
Master´s Degree Project 60 credits in Molecular Biology, 2016
Department of Biology, Lund University (Less)
Please use this url to cite or link to this publication:
author
Sergon, Gladys Wanda
supervisor
organization
course
MOBT01 20152
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
8891807
date added to LUP
2016-09-15 10:54:30
date last changed
2016-09-15 10:54:30
@misc{8891807,
  author       = {Sergon, Gladys Wanda},
  language     = {eng},
  note         = {Student Paper},
  title        = {Helicobacter pylori catalase (KatA) and KatA-associated protein (KapA) interaction},
  year         = {2016},
}