-
Molecular Plant Pathology Mar 2021Plant viruses typically have highly condensed genomes, yet the plant-pathogenic viruses Cassava brown streak virus, Ugandan cassava brown streak virus, and Euphorbia... (Review)
Review
Plant viruses typically have highly condensed genomes, yet the plant-pathogenic viruses Cassava brown streak virus, Ugandan cassava brown streak virus, and Euphorbia ringspot virus are unusual in encoding an enzyme not yet found in any other virus, the "house-cleaning" enzyme inosine triphosphatase. Inosine triphosphatases (ITPases) are highly conserved enzymes that occur in all kingdoms of life and perform a house-cleaning function by hydrolysing the noncanonical nucleotide inosine triphosphate to inosine monophosphate. The ITPases encoded by cassava brown streak virus and Ugandan cassava brown streak virus have been characterized biochemically and are shown to have typical ITPase activity. However, their biological role in virus infection has yet to be elucidated. Here we review what is known of viral-encoded ITPases and speculate on potential roles in infection with the aim of generating a greater understanding of cassava brown streak viruses, a group of the world's most devastating viruses.
Topics: Manihot; Plant Diseases; Potyviridae; Pyrophosphatases; Viral Proteins; Inosine Triphosphatase
PubMed: 33471956
DOI: 10.1111/mpp.13021 -
Retrovirology Aug 2015Retroviruses are among the best studied viruses in last decades due to their pivotal involvement in cellular processes and, most importantly, in causing human diseases,... (Review)
Review
Retroviruses are among the best studied viruses in last decades due to their pivotal involvement in cellular processes and, most importantly, in causing human diseases, most notably-acquired immunodeficiency syndrome (AIDS) that is triggered by human immunodeficiency viruses types 1 and 2 (HIV-1 and HIV-2, respectively). Numerous studied were conducted to understand the involvement of the three cardinal retroviral enzymes, reverse transcriptase, integrase and protease, in the life cycle of the viruses. These studies have led to the development of many inhibitors of these enzymes as anti-retroviral specific drugs that are used for routine treatments of HIV/AIDS patients. Interestingly, a fourth virus-encoded enzyme, the deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase) is also found in several major retroviral groups. The presence and the importance of this enzyme to the life cycle of retroviruses were usually overlooked by most retrovirologists, although the occurrence of dUTPases, particularly in beta-retroviruses and in non-primate retroviruses, is known for more than 20 years. Only more recently, retroviral dUTPases were brought into the limelight and were shown in several cases to be essential for viral replication. Therefore, it is likely that future studies on this enzyme will advance our knowledge to a level that will allow designing novel, specific and potent anti-dUTPase drugs that are effective in combating retroviral diseases. The aim of this review is to give concise background information on dUTPases in general and to summarize the most relevant data on retroviral dUTPases and their involvement in the replication processes and pathogenicity of the viruses, as well as in possibly-associated human diseases.
Topics: Animals; HIV Infections; HIV-1; HIV-2; Humans; Phylogeny; Pyrophosphatases; Retroviridae; Sequence Alignment; Virus Replication
PubMed: 26259899
DOI: 10.1186/s12977-015-0198-9 -
European Journal of Medicinal Chemistry May 2021Ecto-nucleotide pyrophosphatases/phosphodiesterases (NPPs) together with nucleoside triphosphate diphosphohydrolases (NTPDases) and alkaline phosphatases (APs) are...
Synthesis, biological evaluation, and docking studies of novel pyrrolo[2,3-b]pyridine derivatives as both ectonucleotide pyrophosphatase/phosphodiesterase inhibitors and antiproliferative agents.
Ecto-nucleotide pyrophosphatases/phosphodiesterases (NPPs) together with nucleoside triphosphate diphosphohydrolases (NTPDases) and alkaline phosphatases (APs) are nucleotidases located at the surface of the cells. NPP1 and NPP3 are important members of NPP family that are known as druggable targets for a number of disorders such as impaired calcification, type 2 diabetes, and cancer. Sulfonylurea derivatives have been reported as antidiabetic and anticancer agents, therefore, we synthesized and investigated series of sulfonylurea derivatives 1a-m possessing pyrrolo[2,3-b]pyridine core as inhibitors of NPP1 and NPP3 isozymes that are over-expressed in cancer and diabetes. The enzymatic evaluation highlighted compound 1a as selective NPP1 inhibitor, however, 1c was observed as the most potent inhibitor of NPP1 with an IC value of 0.80 ± 0.04 μM. Compound 1l was found to be the most potent and moderately selective inhibitor of NPP3 (IC = 0.55 ± 0.01 μM). Furthermore, in vitro cytotoxicity assays of compounds 1a-m against MCF-7 and HT-29 cancer cell lines exhibited compound 1c (IC = 4.70 ± 0.67 μM), and 1h (IC = 1.58 ± 0.20 μM) as the most cytotoxic compounds against MCF-7 and HT-29 cancer cell lines, respectively. Both of the investigated compounds showed high degree of selectivity towards cancer cells than normal cells (WI-38). Molecular docking studies of selective and potent enzyme inhibitors revealed promising mode of interactions with important binding sites residues of both isozymes i.e., Thr256, His380, Lys255, Asn277 residues of NPP1 and His329, Thr205, and Leu239 residues of NPP3. In addition, the most potent antiproliferative agent, compound 1h, doesn't produce hypoglycemia as a side effect when injected to mice. This is an additional merit of the promising compound 1h.
Topics: Antineoplastic Agents; Cell Proliferation; Cells, Cultured; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Enzyme Inhibitors; Humans; Molecular Docking Simulation; Molecular Structure; Phosphoric Diester Hydrolases; Pyridines; Pyrophosphatases; Pyrroles; Structure-Activity Relationship
PubMed: 33744686
DOI: 10.1016/j.ejmech.2021.113339 -
Pediatrics International : Official... Jul 2021
Topics: Asian People; Humans; Mercaptopurine; Pyrophosphatases
PubMed: 34219339
DOI: 10.1111/ped.14558 -
Plant Biology (Stuttgart, Germany) Nov 2019Cellular pyrophosphate (PPi) homeostasis is vital for normal plant growth and development. Plant proton-pumping pyrophosphatases (H -PPases) are enzymes with different... (Review)
Review
Cellular pyrophosphate (PPi) homeostasis is vital for normal plant growth and development. Plant proton-pumping pyrophosphatases (H -PPases) are enzymes with different tissue-specific functions related to the regulation of PPi homeostasis. Enhanced expression of plant H -PPases increases biomass and yield in different crop species. Here, we emphasise emerging studies utilising heterologous expression in yeast and plant vacuole electrophysiology approaches, as well as phylogenetic relationships and structural analysis, to showcase that the H -PPases possess a PPi synthesis function. We postulate this synthase activity contributes to modulating and promoting plant growth both in H -PPase-engineered crops and in wild-type plants. We propose a model where the PPi synthase activity of H -PPases maintains the PPi pool when cells adopt PPi-dependent glycolysis during high energy demands and/or low oxygen environments. We conclude by proposing experiments to further investigate the H -PPase-mediated PPi synthase role in plant growth.
Topics: Arabidopsis; Arabidopsis Proteins; Diphosphates; Inorganic Pyrophosphatase; Pyrophosphatases
PubMed: 31081197
DOI: 10.1111/plb.13007 -
ChemMedChem Nov 2021Inhibition of membrane-bound pyrophosphatase (mPPase) with small molecules offer a new approach in the fight against pathogenic protozoan parasites. mPPases are absent...
Inhibition of membrane-bound pyrophosphatase (mPPase) with small molecules offer a new approach in the fight against pathogenic protozoan parasites. mPPases are absent in humans, but essential for many protists as they couple pyrophosphate hydrolysis to the active transport of protons or sodium ions across acidocalcisomal membranes. So far, only few nonphosphorus inhibitors have been reported. Here, we explore the chemical space around previous hits using a combination of screening and synthetic medicinal chemistry, identifying compounds with low micromolar inhibitory activities in the Thermotoga maritima mPPase test system. We furthermore provide early structure-activity relationships around a new scaffold having a pyrazolo[1,5-a]pyrimidine core. The most promising pyrazolo[1,5-a]pyrimidine congener was further investigated and found to inhibit Plasmodium falciparum mPPase in membranes as well as the growth of P. falciparum in an ex vivo survival assay.
Topics: Dose-Response Relationship, Drug; Humans; Molecular Structure; Pyrazoles; Pyrimidines; Pyrophosphatases; Structure-Activity Relationship
PubMed: 34459148
DOI: 10.1002/cmdc.202100392 -
Wiley Interdisciplinary Reviews. RNA 2023Inosine triphosphate pyrophosphatase (ITPase), encoded by the ITPA gene in humans, is an important enzyme that preserves the integrity of cellular nucleotide pools by... (Review)
Review
Inosine triphosphate pyrophosphatase (ITPase), encoded by the ITPA gene in humans, is an important enzyme that preserves the integrity of cellular nucleotide pools by hydrolyzing the noncanonical purine nucleotides (deoxy)inosine and (deoxy)xanthosine triphosphate into monophosphates and pyrophosphate. Variants in the ITPA gene can cause partial or complete ITPase deficiency. Partial ITPase deficiency is benign but clinically relevant as it is linked to altered drug responses. Complete ITPase deficiency causes a severe multisystem disorder characterized by seizures and encephalopathy that is frequently associated with fatal infantile dilated cardiomyopathy. In the absence of ITPase activity, its substrate noncanonical nucleotides have the potential to accumulate and become aberrantly incorporated into DNA and RNA. Hence, the pathophysiology of ITPase deficiency could arise from metabolic imbalance, altered DNA or RNA regulation, or from a combination of these factors. Here, we review the known functions of ITPase and highlight recent work aimed at determining the molecular basis for ITPA-associated pathogenesis which provides evidence for RNA dysfunction. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.
Topics: Humans; Nucleotides; RNA; Inosine; Inosine Triphosphate; Pyrophosphatases; DNA
PubMed: 37092460
DOI: 10.1002/wrna.1790 -
Biochemistry and Cell Biology =... Oct 2022Inorganic pyrophosphatase (iPPase) is an enzyme that cleaves pyrophosphate into two phosphate molecules. This enzyme is an essential component of in vitro transcription...
Inorganic pyrophosphatase (iPPase) is an enzyme that cleaves pyrophosphate into two phosphate molecules. This enzyme is an essential component of in vitro transcription (IVT) reactions for RNA preparation as it prevents pyrophosphate from precipitating with magnesium, ultimately increasing the rate of the IVT reaction. Large-scale RNA production is often required for biochemical and biophysical characterization studies of RNA, therefore requiring large amounts of IVT reagents. Commercially purchased iPPase is often the most expensive component of any IVT reaction. In this paper, we demonstrate that iPPase can be produced in large quantities and high quality using a reasonably generic laboratory facility and that laboratory-purified iPPase is as effective as commercially available iPPase. Furthermore, using size exclusion chromatography coupled with multi-angle light scattering and dynamic light scattering, analytical ultracentrifugation, and small-angle X-ray scattering, we demonstrate that yeast iPPase can form tetramers and hexamers in solution as well as the enzymatically active dimer. Our work provides a robust protocol for laboratories involved with RNA in vitro transcription to efficiently produce active iPPase, significantly reducing the financial strain of large-scale RNA production.
Topics: Diphosphates; Inorganic Pyrophosphatase; Magnesium; Pyrophosphatases; RNA
PubMed: 35926232
DOI: 10.1139/bcb-2022-0118 -
Accounts of Chemical Research Apr 2021Bacterial infections caused by multi-drug-resistant Gram-negative pathogens pose a serious threat to public health. Gram-negative bacteria are characterized by the... (Review)
Review
Bacterial infections caused by multi-drug-resistant Gram-negative pathogens pose a serious threat to public health. Gram-negative bacteria are characterized by the enrichment of lipid A-anchored lipopolysaccharide (LPS) or lipooligosaccharide (LOS) in the outer leaflet of their outer membrane. Constitutive biosynthesis of lipid A via the Raetz pathway is essential for bacterial viability and fitness in the human host. The inhibition of early-stage lipid A enzymes such as LpxC not only suppresses the growth of , , Enterobacter spp., and other clinically important Gram-negative pathogens but also sensitizes these bacteria to other antibiotics. The inhibition of late-stage lipid A enzymes such as LpxH is uniquely advantageous because it has an extra mechanism of bacterial killing through the accumulation of toxic lipid A intermediates, rendering LpxH inhibition additionally lethal to . Because essential enzymes of the Raetz pathway have never been exploited by commercial antibiotics, they are excellent targets for the development of novel antibiotics against multi-drug-resistant Gram-negative infections.This Account describes the ongoing research on characterizing the structure and inhibition of LpxC and LpxH, the second and fourth enzymes of the Raetz pathway of lipid A biosynthesis, in the laboratories of Dr. Pei Zhou and Dr. Jiyong Hong at Duke University. Our studies have elucidated the molecular basis of LpxC inhibition by the first broad-spectrum inhibitor, CHIR-090, as well as the mechanism underlying its spectrum of activity. Such an analysis has provided a molecular explanation for the broad-spectrum antibiotic activity of diacetylene-based LpxC inhibitors. Through the structural and biochemical investigation of LpxC inhibition by diacetylene LpxC inhibitors and the first nanomolar LpxC inhibitor, L-161,240, we have elucidated the intrinsic conformational and dynamics difference in individual LpxC enzymes near the active site. A similar approach has been taken to investigate LpxH inhibition, leading to the establishment of the pharmacophore model of LpxH inhibitors and subsequent structural elucidation of LpxH in complex with its first reported small-molecule inhibitor based on a sulfonyl piperazine scaffold.Intriguingly, although our crystallographic analysis of LpxC- and LpxH-inhibitor complexes detected only a single inhibitor conformation in the crystal lattice, solution NMR studies revealed the existence of multiple ligand conformations that together delineate a cryptic ligand envelope expanding the ligand-binding footprint beyond that observed in the crystal structure. By harnessing the ligand dynamics information and structural insights, we demonstrate the feasibility to design potent LpxC and LpxH inhibitors by merging multiple ligand conformations. Such an approach has enabled us to rationally design compounds with significantly enhanced potency in enzymatic assays and outstanding antibiotic activities and in animal models of bacterial infection. We anticipate that continued efforts with structure and ligand dynamics-based lead optimization will ultimately lead to the discovery of LpxC- and LpxH-targeting clinical antibiotics against a broad range of Gram-negative pathogens.
Topics: Amidohydrolases; Anti-Bacterial Agents; Drug Design; Enzyme Inhibitors; Gram-Negative Bacteria; Humans; Ligands; Molecular Dynamics Simulation; Molecular Structure; Pyrophosphatases
PubMed: 33720682
DOI: 10.1021/acs.accounts.0c00880 -
Experimental Dermatology Apr 2022Pseudoxanthoma elasticum (PXE; OMIM 264800) is a rare heritable multisystem disorder, characterized by ectopic mineralization affecting elastic fibres in the skin, eyes...
Pseudoxanthoma elasticum (PXE; OMIM 264800) is a rare heritable multisystem disorder, characterized by ectopic mineralization affecting elastic fibres in the skin, eyes and the cardiovascular system. Skin findings often lead to early diagnosis of PXE, but currently, no specific treatment exists to counteract the progression of symptoms. PXE belongs to a group of Mendelian calcification disorders linked to pyrophosphate metabolism, which also includes generalized arterial calcification of infancy (GACI) and arterial calcification due to CD73 deficiency (ACDC). Inactivating mutations in ABCC6, ENPP1 and NT5E are the genetic cause of these diseases, respectively, and all of them result in reduced inorganic pyrophosphate (PP ) concentration in the circulation. Although PP is a strong inhibitor of ectopic calcification, oral supplementation therapy was initially not considered because of its low bioavailability. Our earlier work however demonstrated that orally administered pyrophosphate inhibits ectopic calcification in the animal models of PXE and GACI, and that orally given Na P O is absorbed in humans. Here, we report that gelatin-encapsulated Na H P O has similar absorption properties in healthy volunteers and people affected by PXE. The sodium-free K H P O form resulted in similar uptake in healthy volunteers and inhibited calcification in Abcc6 mice as effectively as its sodium counterpart. Novel pyrophosphate compounds showing higher bioavailability in mice were also identified. Our results provide an important step towards testing oral PP in clinical trials in PXE, or potentially any condition accompanied by ectopic calcification including diabetes, chronic kidney disease or ageing.
Topics: Animals; Dietary Supplements; Diphosphates; Humans; Mice; Mutation; Phosphoric Diester Hydrolases; Pseudoxanthoma Elasticum; Pyrophosphatases; Vascular Calcification
PubMed: 34758173
DOI: 10.1111/exd.14498