Biomaterial Database

Mechanism of activation of beta-D-2'-deoxy-2'-fluoro-2'-c-methylcytidine and inhibition of hepatitis C virus NS5B RNA polymerase. 2007

Eisuke Murakami, and Haiying Bao, and Mangala Ramesh, and Tamara R McBrayer, and Tony Whitaker, and Holly M Micolochick Steuer, and Raymond F Schinazi, and Lieven J Stuyver, and Aleksandr Obikhod, and Michael J Otto, and Phillip A Furman

Pharmasset, Inc., 303A College Road East, Princeton, NJ 08640, USA. eisuke.murakami@pharmasset.com

Beta-D-2'-deoxy-2'-fluoro-2'-C-methylcytidine (PSI-6130) is a potent specific inhibitor of hepatitis C virus (HCV) RNA synthesis in Huh-7 replicon cells. To inhibit the HCV NS5B RNA polymerase, PSI-6130 must be phosphorylated to the 5'-triphosphate form. The phosphorylation of PSI-6130 and inhibition of HCV NS5B were investigated. The phosphorylation of PSI-6130 by recombinant human 2'-deoxycytidine kinase (dCK) and uridine-cytidine kinase 1 (UCK-1) was measured by using a coupled spectrophotometric reaction. PSI-6130 was shown to be a substrate for purified dCK, with a Km of 81 microM and a kcat of 0.007 s-1, but was not a substrate for UCK-1. PSI-6130 monophosphate (PSI-6130-MP) was efficiently phosphorylated to the diphosphate and subsequently to the triphosphate by recombinant human UMP-CMP kinase and nucleoside diphosphate kinase, respectively. The inhibition of wild-type and mutated (S282T) HCV NS5B RNA polymerases was studied. The steady-state inhibition constant (Ki) for PSI-6130 triphosphate (PSI-6130-TP) with the wild-type enzyme was 4.3 microM. Similar results were obtained with 2'-C-methyladenosine triphosphate (Ki=1.5 microM) and 2'-C-methylcytidine triphosphate (Ki=1.6 microM). NS5B with the S282T mutation, which is known to confer resistance to 2'-C-methyladenosine, was inhibited by PSI-6130-TP as efficiently as the wild type. Incorporation of PSI-6130-MP into RNA catalyzed by purified NS5B RNA polymerase resulted in chain termination.

UI	MeSH Term	Description	Entries
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D010766	Phosphorylation	The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.	Phosphorylations
D002384	Catalysis	The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.	Catalyses
D003841	Deoxycytidine	A nucleoside component of DNA composed of CYTOSINE and DEOXYRIBOSE.	Cytosine Deoxyribonucleoside,Cytosine Deoxyriboside,Deoxyribonucleoside, Cytosine,Deoxyriboside, Cytosine
D006526	Hepatitis C	INFLAMMATION of the LIVER in humans caused by HEPATITIS C VIRUS, a single-stranded RNA virus. Its incubation period is 30-90 days. Hepatitis C is transmitted primarily by contaminated blood parenterally and is often associated with transfusion and intravenous drug abuse. However, in a significant number of cases, the source of hepatitis C infection is unknown.	Hepatitis, Viral, Non-A, Non-B, Parenterally-Transmitted,Parenterally-Transmitted Non-A, Non-B Hepatitis,PT-NANBH,Parenterally Transmitted Non A, Non B Hepatitis
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000998	Antiviral Agents	Agents used in the prophylaxis or therapy of VIRUS DISEASES. Some of the ways they may act include preventing viral replication by inhibiting viral DNA polymerase; binding to specific cell-surface receptors and inhibiting viral penetration or uncoating; inhibiting viral protein synthesis; or blocking late stages of virus assembly.	Antiviral,Antiviral Agent,Antiviral Drug,Antivirals,Antiviral Drugs,Agent, Antiviral,Agents, Antiviral,Drug, Antiviral,Drugs, Antiviral
D012324	RNA-Dependent RNA Polymerase	An enzyme that catalyses RNA-template-directed extension of the 3'- end of an RNA strand by one nucleotide at a time, and can initiate a chain de novo. (Enzyme Nomenclature, 1992, p293)	Nucleoside-Triphosphate:RNA Nucleotidyltransferase (RNA-directed),RNA Replicase,RNA-Dependent RNA Replicase,RNA-Directed RNA Polymerase,RNA Dependent RNA Polymerase,RNA Dependent RNA Replicase,RNA Directed RNA Polymerase,RNA Polymerase, RNA-Dependent,RNA Polymerase, RNA-Directed,RNA Replicase, RNA-Dependent,Replicase, RNA,Replicase, RNA-Dependent RNA
D012367	RNA, Viral	Ribonucleic acid that makes up the genetic material of viruses.	Viral RNA
D013329	Structure-Activity Relationship	The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.	Relationship, Structure-Activity,Relationships, Structure-Activity,Structure Activity Relationship,Structure-Activity Relationships