Molecular approaches for the treatment of hemorrhagic fever virus infections

Andrei, Gracíela; Clercq, Erik De

doi:10.1016/0166-3542(93)90085-w

Cited by 96 publications

(62 citation statements)

References 109 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, using these inhibitors to deplete the intracellular CTP concentration increases the efficacy of the anticancer/antiviral drugs cytosine arabinoside (26,27), 2′,3′-dideoxy-3′-thia-cytidine (28), and 2′,2′-difluoro-2′-deoxycytidine (29). Trypanosoma brucei CTPS is a validated African sleeping sickness drug target (30), and malaria (31), giardiosis (32), chlamydia (33), and hemorrhagic fevers (34) are also potentially treatable using anti-CTPS therapies. However, spontaneous resistance to these drugs arises frequently through clustered CTPS gene mutations that release CTP feedback inhibition and increase intracellular CTP levels (Figures 2 and 6) (18,25,35,36).…”

mentioning

confidence: 99%

Mechanisms of Product Feedback Regulation and Drug Resistance in Cytidine Triphosphate Synthetases from the Structure of a CTP-Inhibited Complex^,

et al. 2005

View full text Add to dashboard Cite

Cytidine triphosphate synthetases (CTPSs) synthesize CTP and regulate its intracellular concentration through direct interactions with the four ribonucleotide triphosphates. In particular, CTP product is a feedback inhibitor that competes with UTP substrate. Selected CTPS mutations that impart resistance to pyrimidine antimetabolite inhibitors also relieve CTP inhibition and cause a dramatic increase in intracellular CTP concentration, indicating that the drugs act by binding to the CTP inhibitory site. Resistance mutations map to a pocket that, although adjacent, does not coincide with the expected UTP binding site in apo Escherichia coli CTPS [EcCTPS; Endrizzi, J. A., et al. (2004) Biochemistry 43, 6447-6463], suggesting allosteric rather than competitive inhibition. Here, bound CTP and ADP were visualized in catalytically active EcCTPS crystals soaked in either ATP and UTP substrates or ADP and CTP products. The CTP cytosine ring resides in the pocket predicted by the resistance mutations, while the triphosphate moiety overlaps the putative UTP triphosphate binding site, explaining how CTP competes with UTP while CTP resistance mutations are acquired without loss of catalytic efficiency. Extensive complementarity and interaction networks at the interfacial binding sites provide the high specificity for pyrimidine triphosphates and mediate nucleotide-dependent tetramer formation. Overall, these results depict a novel product inhibition strategy in which shared substrate and product moieties bind to a single subsite while specificity is conferred by separate subsites. This arrangement allows for independent adaptation of UTP and CTP binding affinities while efficiently utilizing the enzyme surface.Cytidine triphosphate (CTP) is synthesized de novo from uridine triphosphate (UTP), adenosine triphosphate (ATP), and glutamine by cytidine triphosphate synthetases (CTPSs, 1 EC 6.4. 1 Abbreviations: CTPS, cytidine triphosphate synthetase; CPEC, cyclopentenylcytosine; 3deazaU, 3-deazauridine; EcCTPS, Escherichia coli cytidine triphosphate synthetase; ALase, ammonia ligase reaction, i.e., the formation of a carbon-nitrogen bond by displacement of a phosphorylated oxygen; GATase, glutamine amidotransferase, which refers to a conserved glutamine hydrolysis domain that provides ammonia for a number of diverse enzyme-catalyzed reactions; DTBS, E. coli dethiobiotin synthetase (BioD) enzyme; rmsd, root-meansquare difference in position between atom sets, in angstroms. (Figure 1b) (3,4,(11)(12)(13). Further, the product CTP provides negative feedback by acting as a competitive inhibitor of substrate UTP (3,8,9,14), with a comparable K i for CTP (110 μM) and K m for UTP (150 μM) (3) (Figure 1a). This particular interaction determines the upper limit for intracellular CTP, and Saccharomyces cerevisiae carrying CTPS mutants defective in product inhibition exhibit 16-20-fold increased levels (18). NIH Public AccessAntimetabolite pyrimidine analogues cyclopentenylcytosine (CPEC) and 3-deazauridine (3-deazaU) are effectiv...

show abstract

mentioning

confidence: 99%

Mechanisms of Product Feedback Regulation and Drug Resistance in Cytidine Triphosphate Synthetases from the Structure of a CTP-Inhibited Complex^,

et al. 2005

View full text Add to dashboard Cite

show abstract

“…The requirement for de novo CTP makes CTPS activity key to the viability of a number of cancers (29)(30)(31), viruses (32)(33)(34), pathogenic bacteria (35,36), and protozoan parasites (37)(38)(39). As a result, CTPSs are both the targets for therapeutics and responsible for resistance to them by selected mutations.…”

mentioning

confidence: 99%

“…The malarial parasite Plasmodium falciparum (38), intestinal parasite Giardia intestinalis (39), intracellular bacterial pathogen Chlamydia trachomatis (36), and hemorrhagic fever viruses (32) are also potentially treatable by anti-CTPS therapies. The relevance to human diseases make CTPSs attractive targets for structure-based drug discovery.…”

mentioning

confidence: 99%

Crystal Structure of Escherichia coli Cytidine Triphosphate Synthetase, a Nucleotide-Regulated Glutamine Amidotransferase/ATP-Dependent Amidoligase Fusion Protein and Homologue of Anticancer and Antiparasitic Drug Targets^,

et al. 2004

View full text Add to dashboard Cite

Cytidine triphosphate synthetases (CTPSs) produce CTP from UTP and glutamine, and regulate intracellular CTP levels through interactions with the four ribonucleotide triphosphates. We solved the 2.3-Å resolution crystal structure of Escherichia coli CTPS using Hg-MAD phasing. The structure reveals a nearly symmetric 222 tetramer, in which each bifunctional monomer contains a dethiobiotin synthetase-like amidoligase N-terminal domain and a Type 1 glutamine amidotransferase C-terminal domain. For each amidoligase active site, essential ATP-and UTPbinding surfaces are contributed by three monomers, suggesting that activity requires tetramer formation, and that a nucleotide-dependent dimer-tetramer equilibrium contributes to the observed positive cooperativity. A gated channel that spans 25 Å between the glutamine hydrolysis and amidoligase active sites provides a path for ammonia diffusion. The channel is accessible to solvent at the base of a cleft adjoining the glutamine hydrolysis active site, providing an entry point for exogenous ammonia. Guanine nucleotide binding sites of structurally related GTPases superimpose on this cleft, providing insights into allosteric regulation by GTP. Mutations that confer nucleoside drug resistance and release CTP inhibition map to a pocket that neighbors the UTP-binding site and can accommodate a pyrimidine ring. Its location suggests that competitive feedback inhibition is affected via a distinct product/drug binding site that overlaps the substrate triphosphate binding site. Overall, the E. coli structure provides a framework for homology modeling of other CTPSs and structure-based design of anti-CTPS therapeutics. † This work was funded by the UC Systemwide Biotechnology Training Program Grant #2002-07, and the National Institutes of Health, General Medical Sciences, #GM63109. ‡ Protein Data Bank accession number 1S1M. NIH Public Access Author ManuscriptBiochemistry. Author manuscript; available in PMC 2010 June 24. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptCytidine triphosphate synthetases (CTPSs, 1 E. C. 6.4.3.2, uridine triphosphate ammonia lyases, 525-630 amino acid residues) are essential ubiquitous enzymes that catalyze the ratelimiting step of de novo CTP biosynthesis (1,2). Genes pyrG (bacteria), ctrA (some gram positive bacteria), URA7 and URA8 (Saccharomyces cerevisiae), and CTPS1 and CTPS2 (human) encode CTP synthetase enzymes, with most eukaryotes expressing two isoforms.CTPSs not only provide a key precursor for synthesis of DNA, RNA, and phospholipid (3,4), they also control the intracellular CTP concentrations that limit these processes (5-9).CTP is derived from UTP in three reaction steps catalyzed by CTPSs (Figure 1a). In one active site, the UTP O4 oxygen is activated by Mg-ATP-dependent phosphorylation, followed by displacement of the resulting 4-phosphate moiety by ammonia (10,11). In a separate site, ammonia is generated via rate-limiting glutamine hydrolysis (glutaminase) activity (12). CTPS activity was first re...

show abstract

“…Notably, the antiviral and mutagenic activities of ribavirin could not be accounted for solely by depletion of intracellular GTP levels, which are a consequence of IMPDH inhibition (24)(25)(26)(27)(28). Several other compounds, including cytidine analogs that target cytosine triphosphate synthetase (29), analogs of adenosine that target S-adenosylhomocysteine hydrolase and interfere with the 5= cap of mRNA (30), and carbanucleoside analogs that target orotidylic acid decarboxylase (OMPD) and inhibit the conversion of OMP to UMP (31), have been shown to have antiarenaviral activities but did not exhibit advantages over ribavirin (25). Recently, a screen for inhibitors of influenza virus replication in cultured cells identified the de novo pyrimidine biosynthesis inhibitor compound A3 (32), which was found to have a broad inhibitory effect on multiplication of several other RNA viruses, including Newcastle disease virus, vesicular stomatitis virus, Sindbis virus, hepatitis C virus, West Nile virus, and dengue virus (32).…”

mentioning

confidence: 99%

Inhibition of Arenavirus by A3, a Pyrimidine Biosynthesis Inhibitor

Ortiz-Riaño

Ngo

DeVito

et al. 2014

J Virol

View full text Add to dashboard Cite

dArenaviruses merit significant interest as important human pathogens, since several of them cause severe hemorrhagic fever disease that is associated with high morbidity and significant mortality. Currently, there are no FDA-licensed arenavirus vaccines available, and current antiarenaviral therapy is limited to an off-labeled use of the nucleoside analog ribavirin, which has limited prophylactic efficacy. The pyrimidine biosynthesis inhibitor A3, which was identified in a high-throughput screen for compounds that blocked influenza virus replication, exhibits a broad-spectrum antiviral activity against negative-and positive-sense RNA viruses, retroviruses, and DNA viruses. In this study, we evaluated the antiviral activity of A3 against representative Old World (lymphocytic choriomeningitis virus) and New World (Junin virus) arenaviruses in rodent, monkey, and human cell lines. We show that A3 is significantly more efficient than ribavirin in controlling arenavirus multiplication and that the A3 inhibitory effect is in part due to its ability to interfere with viral RNA replication and transcription. We document an additive antiarenavirus effect of A3 and ribavirin, supporting the potential combination therapy of ribavirin and pyrimidine biosynthesis inhibitors for the treatment of arenavirus infections.

show abstract

Molecular approaches for the treatment of hemorrhagic fever virus infections

Cited by 96 publications

References 109 publications

Mechanisms of Product Feedback Regulation and Drug Resistance in Cytidine Triphosphate Synthetases from the Structure of a CTP-Inhibited Complex^,

Mechanisms of Product Feedback Regulation and Drug Resistance in Cytidine Triphosphate Synthetases from the Structure of a CTP-Inhibited Complex^,

Crystal Structure of Escherichia coli Cytidine Triphosphate Synthetase, a Nucleotide-Regulated Glutamine Amidotransferase/ATP-Dependent Amidoligase Fusion Protein and Homologue of Anticancer and Antiparasitic Drug Targets^,

Inhibition of Arenavirus by A3, a Pyrimidine Biosynthesis Inhibitor

Contact Info

Product

Resources

About

Molecular approaches for the treatment of hemorrhagic fever virus infections

Cited by 96 publications

References 109 publications

Mechanisms of Product Feedback Regulation and Drug Resistance in Cytidine Triphosphate Synthetases from the Structure of a CTP-Inhibited Complex,

Mechanisms of Product Feedback Regulation and Drug Resistance in Cytidine Triphosphate Synthetases from the Structure of a CTP-Inhibited Complex,

Crystal Structure of Escherichia coli Cytidine Triphosphate Synthetase, a Nucleotide-Regulated Glutamine Amidotransferase/ATP-Dependent Amidoligase Fusion Protein and Homologue of Anticancer and Antiparasitic Drug Targets,

Inhibition of Arenavirus by A3, a Pyrimidine Biosynthesis Inhibitor

Contact Info

Product

Resources

About

Mechanisms of Product Feedback Regulation and Drug Resistance in Cytidine Triphosphate Synthetases from the Structure of a CTP-Inhibited Complex^,

Mechanisms of Product Feedback Regulation and Drug Resistance in Cytidine Triphosphate Synthetases from the Structure of a CTP-Inhibited Complex^,

Crystal Structure of Escherichia coli Cytidine Triphosphate Synthetase, a Nucleotide-Regulated Glutamine Amidotransferase/ATP-Dependent Amidoligase Fusion Protein and Homologue of Anticancer and Antiparasitic Drug Targets^,