Dataset Information

The Helicobacter pylori HypA·UreE2 Complex Contains a Novel High-Affinity Ni(II)-Binding Site.

ABSTRACT: Helicobacter pylori is a human pathogen that colonizes the stomach, is the major cause of ulcers, and has been associated with stomach cancers. To survive in the acidic environment of the stomach, H. pylori uses urease, a nickel-dependent enzyme, to produce ammonia for maintenance of cellular pH. The bacteria produce apo-urease in large quantities and activate it by incorporating nickel under acid shock conditions. Urease nickel incorporation requires the urease-specific metallochaperone UreE and the (UreFGH)2 maturation complex. In addition, the H. pylori nickel urease maturation pathway recruits accessory proteins from the [NiFe] hydrogenase maturation pathway, namely, HypA and HypB. HypA and UreE dimers (UreE2) are known to form a protein complex, the role of which in urease maturation is largely unknown. Herein, we examine the nickel-binding properties and protein-protein interactions of HypA and UreE2 using isothermal titration calorimetry and fluorometric methods under neutral and acidic pH conditions to gain insight into the roles played by HypA in urease maturation. The results reveal that HypA and UreE2 form a stable complex with micromolar affinity that protects UreE from hydrolytic degradation. The HypA·UreE2 complex contains a unique high-affinity (nanomolar) Ni2+-binding site that is maintained under conditions designed to mimic acid shock (pH 6.3). The data are interpreted in terms of a proposed mechanism wherein HypA and UreE2 act as co-metallochaperones that target the delivery of Ni2+ to apo-urease with high fidelity.

SUBMITTER: Hu HQ

PROVIDER: S-EPMC6260798 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

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The Helicobacter pylori HypA·UreE<sub>2</sub> Complex Contains a Novel High-Affinity Ni(II)-Binding Site.

Hu Heidi Q HQ Huang Hsin-Ting HT Maroney Michael J MJ

Biochemistry 20180510 20

Helicobacter pylori is a human pathogen that colonizes the stomach, is the major cause of ulcers, and has been associated with stomach cancers. To survive in the acidic environment of the stomach, H. pylori uses urease, a nickel-dependent enzyme, to produce ammonia for maintenance of cellular pH. The bacteria produce apo-urease in large quantities and activate it by incorporating nickel under acid shock conditions. Urease nickel incorporation requires the urease-specific metallochaperone UreE an ...[more]

PMID: 29708738

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Project description:Helicobacter pylori colonizes the stomach of half of the human population. Most H. pylori are located in the mucus layer, which is mainly comprised by glycosylated mucins. Using mass spectrometry, we identified 631 glycans (whereof 145 were fully characterized and the remainder assigned as compositions) on mucins isolated from 14 Helicobacter spp.-infected and 14 Helicobacter spp.-noninfected stomachs. Only six identified glycans were common to all individuals, from a total of 60 to 189 glycans in each individual. An increased number of unique glycan structures together with an increased intraindividual diversity and larger interindividual variation were identified among O-glycans from Helicobacter spp.-infected stomachs compared with noninfected stomachs. H. pylori strain J99, which carries the blood group antigen-binding adhesin (BabA), the sialic acid-binding adhesin (SabA), and the LacdiNAc-binding adhesin, bound both to Lewis b (Leb)-positive and Leb-negative mucins. Among Leb-positive mucins, H. pylori J99 binding was higher to mucins from Helicobacter spp.-infected individuals than noninfected individuals. Statistical correlation analysis, binding experiments with J99 wt, and J99ΔbabAΔsabA and inhibition experiments using synthetic glycoconjugates demonstrated that the differences in H. pylori-binding ability among these four groups were governed by BabA-dependent binding to fucosylated structures. LacdiNAc levels were lower in mucins that bound to J99 lacking BabA and SabA than in mucins that did not, suggesting that LacdiNAc did not significantly contribute to the binding. We identified 24 O-glycans from Leb-negative mucins that correlated well with H. pylori binding whereof 23 contained α1,2-linked fucosylation. The large and diverse gastric glycan library identified, including structures that correlated with H. pylori binding, could be used to select glycodeterminants to experimentally investigate further for their importance in host-pathogen interactions and as candidates to develop glycan-based therapies.

Dataset Information

The Helicobacter pylori HypA·UreE2 Complex Contains a Novel High-Affinity Ni(II)-Binding Site.

Publications

The Helicobacter pylori HypA·UreE<sub>2</sub> Complex Contains a Novel High-Affinity Ni(II)-Binding Site.

Similar Datasets

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