Structural characterization of purine nucleoside phosphorylase from human pathogen Helicobacter pylori

Štefanić, Zoran; Mikleušević, Goran; Luić, Marija; Bzowska, Agnieszka; Ašler, Ivana Leščić

doi:10.1016/j.ijbiomac.2017.03.101

Cited by 12 publications

(19 citation statements)

References 36 publications

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“…Furthermore, this leads to the closing of only one out of six active sites. This arrangement of active sites was previously noted only in the case of two other crystal structures of HpPNP-Zg [13]. In a general survey of all structures of PNPs deposited in the PDB, these represent the only structures with a single closed active site [12], which seems to be a unique feature of H. pylori PNPs.…”

Section: Discussionmentioning

confidence: 72%

“…X‐ray structures also served as a starting point for a series of MD simulations. Previously, we described the elementary catalytic properties and X‐ray structure of PNP from a clinical isolate of pathogen H. pylori (HpPNP‐Zg) . The difference between PNP from H. pylori strain ATCC 26695 (UniProt code http://www.uniprot.org/uniprot/P56463) and HpPNP‐Zg is in only four amino acids (position 55: Arg → Lys, position 150: Val → Ile, position 172: Lys → Gln, and position 218: Val → Ile in HpPNP and HpPNP‐Zg respectively).…”

Section: Discussionmentioning

confidence: 99%

“…Purification of overexpressed protein was performed essentially as described by Štefanić et al . for HpPNP‐Zg . The purification was monitored by an activity assay and a protein concentration assay following the Bradford method with bovine serum albumin as a standard.…”

Section: Methodsmentioning

confidence: 99%

“…For many years we have been studying a homohexameric enzyme purine nucleoside phosphorylase (PNP, purine nucleoside orthophosphate ribosyl transferase, http://www.chem.qmul.ac.uk/iubmb/enzyme/EC2.4.2.1.html) and the conformational changes of its six active sites upon ligand binding, with the final goal of understanding the highly complex mechanism of this enzyme action . PNP catalyses the reversible phosphorolytic cleavage of the glycosidic bond of purine ribo‐ and deoxyribonucleosides:

(deoxy)purine nucleoside + orthophosphate = purine base + (2^{'} ‐deoxy)ribose‐1‐phosphate .

…”

Section: Introductionmentioning

confidence: 99%

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Helicobacter pylori purine nucleoside phosphorylase shows new distribution patterns of open and closed active site conformations and unusual biochemical features

et al. 2018

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Section: Discussionmentioning

confidence: 72%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

(deoxy)purine nucleoside + orthophosphate = purine base + (2^{'} ‐deoxy)ribose‐1‐phosphate .

…”

Section: Introductionmentioning

confidence: 99%

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Helicobacter pylori purine nucleoside phosphorylase shows new distribution patterns of open and closed active site conformations and unusual biochemical features

et al. 2018

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“…[1] Although much progress has been made over the years of our research on PNP from E. coli, the complete blueprint of the catalytic mechanism of PNP is yet to be drawn. [2][3][4][5][6][7][8] What makes PNP an attractive target for the fight against this severe pathogen is the fact that this bacterium relies exclusively on the purine salvage pathway for the synthesis of purine nucleosides, and in this pathway the PNP plays a key role. [9] For that reason inhibiting this enzyme would cut down the only source of nucleosides and ultimately would lead to its eradication.…”

Section: Introductionmentioning

confidence: 99%

The Role of Phosphate Binding in Purine Nucleoside Phosphorylase of Helicobacter pylori

2018

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Purine nucleoside phosphorylase (PNP) is an essential enzyme in the purine salvage pathway of Helicobacter pylori. Since H. pylori lacks the ability to synthesize purine nucleosides de novo, inhibition of this enzyme could stop the growth of this bacterium. However, for the design of successful inhibitors the details of the mechanism of this enzyme should be fully understood. PNPs catalyze cleavage of the glycosidic bond of purine nucleosides, and phosphate is one of the substrates. It is thought that binding of phosphate induces the conformational change as a necessary initial step in the catalysis. This conformational change is manifested in closing of either one of the six active sites in the homohexameric PNPs. It is unclear whether the binding of phosphate is sufficient or just a necessary condition for the closing of the active site. In this paper we conducted an experiment to check this by soaking the crystals of the apo form of the enzyme in increasing concentrations of phosphate.

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Helicobacter pylori treatment in the post-antibiotics era—searching for new drug targets

Roszczenko-Jasińska

Wojtyś

Jagusztyn-Krynicka

2020

Appl Microbiol Biotechnol

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Helicobacter pylori, a member of Epsilonproteobacteria, is a Gram-negative microaerophilic bacterium that colonizes gastric mucosa of about 50% of the human population. Although most infections caused by H. pylori are asymptomatic, the microorganism is strongly associated with serious diseases of the upper gastrointestinal tract such as chronic gastritis, peptic ulcer, duodenal ulcer, and gastric cancer, and it is classified as a group I carcinogen. The prevalence of H. pylori infections varies worldwide. The H. pylori genotype, host gene polymorphisms, and environmental factors determine the type of induced disease. Currently, the most common therapy to treat H. pylori is the first line clarithromycin–based triple therapy or a quadruple therapy replacing clarithromycin with new antibiotics. Despite the enormous recent effort to introduce new therapeutic regimens to combat this pathogen, treatment for H. pylori still fails in more than 20% of patients, mainly due to the increased prevalence of antibiotic resistant strains. In this review we present recent progress aimed at designing new anti-H. pylori strategies to combat this pathogen. Some novel therapeutic regimens will potentially be used as an extra constituent of antibiotic therapy, and others may replace current antibiotic treatments. Key points • Attempts to improve eradication rate of H. pylori infection. • Searching for new drug targets in anti-Helicobacter therapies.

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Structural characterization of purine nucleoside phosphorylase from human pathogen Helicobacter pylori

Cited by 12 publications

References 36 publications

Helicobacter pylori purine nucleoside phosphorylase shows new distribution patterns of open and closed active site conformations and unusual biochemical features

Helicobacter pylori purine nucleoside phosphorylase shows new distribution patterns of open and closed active site conformations and unusual biochemical features

The Role of Phosphate Binding in Purine Nucleoside Phosphorylase of Helicobacter pylori

Helicobacter pylori treatment in the post-antibiotics era—searching for new drug targets

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