The Hsp60 protein of helicobacter pylori displays chaperone activity under acidic conditions
نویسندگان
چکیده
The heat shock protein, Hsp60, is one of the most abundant proteins in Helicobacter pylori. Given its sequence homology to the Escherichia coli Hsp60 or GroEL, Hsp60 from H. pylori would be expected to function as a molecular chaperone in this organism. H. pylori is an organism that grows on the gastric epithelium, where the pH can fluctuate between neutral and 4.5 and the intracellular pH can be as low as 5.0. This study was performed to test the ability of Hsp60 from H. pylori to function as a molecular chaperone under mildly acidic conditions. We report here that Hsp60 could suppress the acid-induced aggregation of alcohol dehydrogenase (ADH) in the 7.0-5.0 pH range. Hsp60 was found to undergo a conformational change within this pH range. It was also found that exposure of hydrophobic surfaces of Hsp60 is significant and that their exposure is increased under acidic conditions. Although, alcohol dehydrogenase does not contain exposed hydrophobic surfaces, we found that their exposure is triggered at low pH. Our results demonstrate that Hsp60 from H. pylori can function as a molecular chaperone under acidic conditions and that the interaction between Hsp60 and other proteins may be mediated by hydrophobic interactions.
منابع مشابه
Flow cytometric analysis of the heat shock protein 60 expressed on the cell surface of Helicobacter pylori.
The expression of a 60-kDa heat shock protein (HSP60) on the cell surface of Helicobacter pylori was analysed by flow cytometry with polyclonal antibody directed to HSP60. All 13 strains of H. pylori examined expressed HSP60 on the cell surface, although the intensity of expression was different among the strains and depended on culture conditions. There was a correlation between the intensity ...
متن کاملThe antioxidant protein alkylhydroperoxide reductase of Helicobacter pylori switches from a peroxide reductase to a molecular chaperone function.
Helicobacter pylori, an oxygen-sensitive microaerophilic bacterium, contains many antioxidant proteins, among which alkylhydroperoxide reductase (AhpC) is the most abundant. The function of AhpC is to protect H. pylori from a hyperoxidative environment by reduction of toxic organic hydroperoxides. We have found that the sequence of AhpC from H. pylori is more homologous to mammalian peroxiredox...
متن کاملHelicobacter pylori heat shock protein 60 mediates interleukin-6 production by macrophages via a toll-like receptor (TLR)-2-, TLR-4-, and myeloid differentiation factor 88-independent mechanism.
Helicobacter pylori has been reported to induce interleukin-6 (IL-6) production in monocytes/macrophages and in chronically inflamed gastric tissues. The mechanism by which H. pylori induces IL-6 production in macrophages, however, has not been investigated. To identify the H. pylori factor responsible for this activity, we fractionated soluble proteins from H. pylori strain 26695 by ion exchan...
متن کاملEffect of bacterial flora on postimmunization gastritis following oral vaccination of mice with Helicobacter pylori heat shock protein 60.
In order to assess the efficacy of oral Helicobacter pylori heat shock protein 60 (HSP60) as a vaccine, protection against H. pylori infection in specific-pathogen-free (SPF) C57BL/6 and germfree (GF) IQI mice was examined. Prophylactic oral vaccination of these two strains of mice with either H. pylori HSP60 or Escherichia coli GroEL inhibited H. pylori colonization by 90 to 95% at 3 weeks pos...
متن کاملHelicobacter pylori is killed by nitrite under acidic conditions.
BACKGROUND Due to the expression of urease, Helicobacter pylori is able to establish itself in the human stomach under acidic conditions. A novel host defence mechanism was recently proposed, suggesting that the formation of salivary nitrite in symbiosis with facultative anaerobic bacteria in the oropharynx, is aimed at enhancing the antimicrobial activity of gastric juice. AIMS To investigat...
متن کامل