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[PMID]:28346939
[Au] Autor:Bridwell-Rabb J; Zhong A; Sun HG; Drennan CL; Liu HW
[Ad] Endereço:Howard Hughes Medical Institute, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
[Ti] Título:A B -dependent radical SAM enzyme involved in oxetanocin A biosynthesis.
[So] Source:Nature;544(7650):322-326, 2017 04 20.
[Is] ISSN:1476-4687
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Oxetanocin A (OXT-A) is a potent antitumour, antiviral and antibacterial compound. Biosynthesis of OXT-A has been linked to a plasmid-borne Bacillus megaterium gene cluster that contains four genes: oxsA, oxsB, oxrA and oxrB. Here we show that both the oxsA and oxsB genes are required for the production of OXT-A. Biochemical analysis of the encoded proteins, a cobalamin (Cbl)-dependent S-adenosylmethionine (AdoMet) radical enzyme, OxsB, and an HD-domain phosphohydrolase, OxsA, reveals that OXT-A is derived from a 2'-deoxyadenosine phosphate in an OxsB-catalysed ring contraction reaction initiated by hydrogen atom abstraction from C2'. Hence, OxsB represents the first biochemically characterized non-methylating Cbl-dependent AdoMet radical enzyme. X-ray analysis of OxsB reveals the fold of a Cbl-dependent AdoMet radical enzyme, a family of enzymes with an estimated 7,000 members. Overall, this work provides a framework for understanding the interplay of AdoMet and Cbl cofactors and expands the catalytic repertoire of Cbl-dependent AdoMet radical enzymes.
[Mh] Termos MeSH primário: Adenina/análogos & derivados
Bacillus megaterium/enzimologia
Proteínas de Bactérias/metabolismo
Biocatálise
Coenzimas/metabolismo
S-Adenosilmetionina/metabolismo
Vitamina B 12/metabolismo
[Mh] Termos MeSH secundário: Adenina/biossíntese
Monofosfato de Adenosina/metabolismo
Bacillus megaterium/genética
Bacillus megaterium/metabolismo
Proteínas de Bactérias/química
Proteínas de Bactérias/genética
Cristalografia por Raios X
Nucleotídeos de Desoxiadenina/metabolismo
Genes Bacterianos/genética
Modelos Moleculares
Família Multigênica/genética
Conformação Proteica
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Coenzymes); 0 (Deoxyadenine Nucleotides); 103913-16-2 (oxetanocin); 415SHH325A (Adenosine Monophosphate); 7LP2MPO46S (S-Adenosylmethionine); JAC85A2161 (Adenine); P6YC3EG204 (Vitamin B 12)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170927
[Lr] Data última revisão:
170927
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170328
[St] Status:MEDLINE
[do] DOI:10.1038/nature21689


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[PMID]:28321930
[Au] Autor:Patra KK; Bhattacharya A; Bhattacharya S
[Ad] Endereço:Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India, 400076.
[Ti] Título:Uncovering allostery and regulation in SAMHD1 through molecular dynamics simulations.
[So] Source:Proteins;85(7):1266-1275, 2017 Jul.
[Is] ISSN:1097-0134
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The human sterile alpha motif and HD domain-containing protein 1 (SAMHD1) is a retroviral restriction factor in myeloid cells and non-cycling CD4+ T cells, a feature imputed to its phosphohydrolase activity-the enzyme depletes the cellular dNTP levels inhibiting reverse transcription. The functionally active form of SAMHD1 is an allosterically triggered tetramer which utilizes GTP-Mg -dNTP cross bridges to link and stabilize adjacent monomers. However, very little is known about how it assembles into a tetramer and how long the tetramer stays intact. In this computational study, we provide a molecular dynamics based analysis of the structural stability and allosteric site dynamics in SAMHD1. We have investigated the allosteric links which assemble and hold the tetramer together. We have also extended this analysis to a regulatory mutant of SAMHD1. Experimental studies have indicated that phosphorylation of T592 downregulates HIV-1 restriction. A similar result is also achieved by a phosphomimetic mutation T592E. While a mechanistic understanding of the process is still elusive, the loss of structural integrity of the enzyme is conjectured to be the cause of the impaired dNTPase activity of the T592E mutant. MD simulations show that the T592E mutation causes slightly elevated local motions which remain confined to the short helix (residues 591-595), which contains the phosphorylation site and do not cause long-range destabilization of the SAMHD1 tetramer within the timeframe of the simulations. Thus, the regulatory mechanism of SAMHD1 is a more subtle mechanism than has been previously suspected. Proteins 2017; 85:1266-1275. © 2017 Wiley Periodicals, Inc.
[Mh] Termos MeSH primário: Nucleotídeos de Desoxiadenina/química
Ácido Glutâmico/química
Guanosina Trifosfato/química
Proteínas Monoméricas de Ligação ao GTP/química
Treonina/química
[Mh] Termos MeSH secundário: Regulação Alostérica
Sítio Alostérico
Substituição de Aminoácidos
Nucleotídeos de Desoxiadenina/metabolismo
Ácido Glutâmico/metabolismo
Guanosina Trifosfato/metabolismo
Seres Humanos
Cinética
Magnésio
Simulação de Dinâmica Molecular
Proteínas Monoméricas de Ligação ao GTP/metabolismo
Mutação
Fosforilação
Ligação Proteica
Conformação Proteica em alfa-Hélice
Domínios e Motivos de Interação entre Proteínas
Multimerização Proteica
Estrutura Terciária de Proteína
Proteína 1 com Domínio SAM e Domínio HD
Especificidade por Substrato
Treonina/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Deoxyadenine Nucleotides); 2ZD004190S (Threonine); 3KX376GY7L (Glutamic Acid); 86-01-1 (Guanosine Triphosphate); EC 3.1.5.- (SAM Domain and HD Domain-Containing Protein 1); EC 3.1.5.- (SAMHD1 protein, human); EC 3.6.5.2 (Monomeric GTP-Binding Proteins); I38ZP9992A (Magnesium); K8KCC8SH6N (2'-deoxyadenosine triphosphate)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170322
[St] Status:MEDLINE
[do] DOI:10.1002/prot.25287


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[PMID]:28290677
[Au] Autor:Wilson KA; Wetmore SD
[Ad] Endereço:Department of Chemistry and Biochemistry, University of Lethbridge , 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada.
[Ti] Título:Molecular Insights into the Translesion Synthesis of Benzyl-Guanine from Molecular Dynamics Simulations: Structural Evidence of Mutagenic and Nonmutagenic Replication.
[So] Source:Biochemistry;56(13):1841-1853, 2017 Apr 04.
[Is] ISSN:1520-4995
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:DNA can be damaged by many compounds in our environment, and the resulting damaged DNA is commonly replicated by translesion synthesis (TLS) polymerases. Because the mechanism and efficiency of TLS are affected by the type of DNA damage, obtaining information for a variety of DNA adducts is critical. However, there is no structural information for the insertion of a dNTP opposite an O6-dG adduct, which is a particularly harmful class of DNA lesions. We used molecular dynamics (MD) simulations to investigate structural and energetic parameters that dictate preferred dNTP insertion opposite O6-benzyl-guanine (Bz-dG) by DNA polymerase IV, a prototypical TLS polymerase. Specifically, MD simulations were completed on all possible ternary insertion complexes and ternary -1 base deletion complexes with different Bz-dG conformations. Our data suggests that the purines are unlikely to be inserted opposite anti- or syn-Bz-dG, and dTTP is unlikely to be inserted opposite syn-Bz-dG, because of changes in the active site conformation, including critical hydrogen-bonding interactions and/or reaction-ready parameters compared to natural dG replication. In contrast, a preserved active site conformation suggests that dCTP can be inserted opposite either anti- or syn-Bz-dG and dTTP can be inserted opposite anti-Bz-dG. This is the first structural explanation for the experimentally observed preferential insertion of dCTP and misincorporation of dTTP opposite Bz-dG. Furthermore, we provide atomic level insight into why Bz-dG replication does not lead to deletion mutations, which is in contrast with the replication outcomes of other adducts. These findings provide a basis for understanding the replication of related O6-dG adducts.
[Mh] Termos MeSH primário: Compostos de Benzil/síntese química
Adutos de DNA/química
DNA Polimerase beta/química
Reparo do DNA
Replicação do DNA
Nucleotídeos de Desoxiguanina/química
Proteínas de Escherichia coli/química
Guanina/síntese química
[Mh] Termos MeSH secundário: Domínio Catalítico
Dano ao DNA
DNA Polimerase beta/genética
DNA Polimerase beta/metabolismo
Nucleotídeos de Desoxiadenina/química
Nucleotídeos de Desoxiadenina/metabolismo
Nucleotídeos de Desoxicitosina/química
Nucleotídeos de Desoxicitosina/metabolismo
Nucleotídeos de Desoxiguanina/metabolismo
Escherichia coli/química
Escherichia coli/enzimologia
Escherichia coli/genética
Proteínas de Escherichia coli/genética
Proteínas de Escherichia coli/metabolismo
Guanina/análogos & derivados
Ligações de Hidrogênio
Simulação de Dinâmica Molecular
Mutagênese
Estrutura Secundária de Proteína
Estrutura Terciária de Proteína
Nucleotídeos de Timina/química
Nucleotídeos de Timina/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Benzyl Compounds); 0 (DNA Adducts); 0 (Deoxyadenine Nucleotides); 0 (Deoxycytosine Nucleotides); 0 (Deoxyguanine Nucleotides); 0 (Escherichia coli Proteins); 0 (Thymine Nucleotides); 2056-98-6 (2'-deoxycytidine 5'-triphosphate); 5Z93L87A1R (Guanine); 8C2O37Y44Q (deoxyguanosine triphosphate); EC 2.7.7.- (DNA Polymerase beta); EC 2.7.7.- (Dpo4 protein, E coli); K8KCC8SH6N (2'-deoxyadenosine triphosphate); QOP4K539MU (thymidine 5'-triphosphate)
[Em] Mês de entrada:1705
[Cu] Atualização por classe:170515
[Lr] Data última revisão:
170515
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170315
[St] Status:MEDLINE
[do] DOI:10.1021/acs.biochem.6b01247


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[PMID]:28130843
[Au] Autor:Babu VMP; Itsko M; Baxter JC; Schaaper RM; Sutton MD
[Ad] Endereço:Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, USA.
[Ti] Título:Insufficient levels of the nrdAB-encoded ribonucleotide reductase underlie the severe growth defect of the Δhda E. coli strain.
[So] Source:Mol Microbiol;104(3):377-399, 2017 May.
[Is] ISSN:1365-2958
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The ATP-bound form of the Escherichia coli DnaA replication initiator protein remodels the chromosomal origin of replication, oriC, to load the replicative helicase. The primary mechanism for regulating the activity of DnaA involves the Hda and ß clamp proteins, which act together to dramatically stimulate the intrinsic DNA-dependent ATPase activity of DnaA via a process termed Regulatory Inactivation of DnaA. In addition to hyperinitiation, strains lacking hda function also exhibit cold sensitive growth at 30°C. Strains impaired for the other regulators of initiation (i.e., ΔseqA or ΔdatA) fail to exhibit cold sensitivity. The goal of this study was to gain insight into why loss of hda function impedes growth. We used a genetic approach to isolate 9 suppressors of Δhda cold sensitivity, and characterized the mechanistic basis by which these suppressors alleviated Δhda cold sensitivity. Taken together, our results provide strong support for the view that the fundamental defect associated with Δhda is diminished levels of DNA precursors, particularly dGTP and dATP. We discuss possible mechanisms by which the suppressors identified here may regulate dNTP pool size, as well as similarities in phenotypes between the Δhda strain and hda strains exposed to the ribonucleotide reductase inhibitor hydroxyurea.
[Mh] Termos MeSH primário: Proteínas de Escherichia coli/genética
Proteínas de Escherichia coli/metabolismo
Escherichia coli/genética
Ribonucleosídeo Difosfato Redutase/genética
Ribonucleosídeo Difosfato Redutase/metabolismo
[Mh] Termos MeSH secundário: Adenosina Trifosfatases/metabolismo
Alelos
Temperatura Baixa
DNA Helicases/genética
DNA Helicases/metabolismo
Replicação do DNA
DNA Bacteriano/genética
DNA Bacteriano/metabolismo
Proteínas de Ligação a DNA/metabolismo
Nucleotídeos de Desoxiadenina/genética
Nucleotídeos de Desoxiadenina/metabolismo
Escherichia coli/enzimologia
Escherichia coli/crescimento & desenvolvimento
Transativadores/genética
Transativadores/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (DNA, Bacterial); 0 (DNA-Binding Proteins); 0 (Deoxyadenine Nucleotides); 0 (Escherichia coli Proteins); 0 (Trans-Activators); 0 (replication initiator protein); EC 1.17.4.1 (NrdA protein, E coli); EC 1.17.4.1 (Ribonucleoside Diphosphate Reductase); EC 3.6.1.- (Adenosine Triphosphatases); EC 3.6.4.- (DNA Helicases); K8KCC8SH6N (2'-deoxyadenosine triphosphate)
[Em] Mês de entrada:1705
[Cu] Atualização por classe:170530
[Lr] Data última revisão:
170530
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170129
[St] Status:MEDLINE
[do] DOI:10.1111/mmi.13632


  5 / 1042 MEDLINE  
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[PMID]:28097776
[Au] Autor:Nowakowski SG; Regnier M; Daggett V
[Ad] Endereço:Department of Bioengineering, University of Washington, Seattle, Washington, 98195-5013.
[Ti] Título:Molecular mechanisms underlying deoxy-ADP.Pi activation of pre-powerstroke myosin.
[So] Source:Protein Sci;26(4):749-762, 2017 Apr.
[Is] ISSN:1469-896X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Myosin activation is a viable approach to treat systolic heart failure. We previously demonstrated that striated muscle myosin is a promiscuous ATPase that can use most nucleoside triphosphates as energy substrates for contraction. When 2-deoxy ATP (dATP) is used, it acts as a myosin activator, enhancing cross-bridge binding and cycling. In vivo, we have demonstrated that elevated dATP levels increase basal cardiac function and rescues function of infarcted rodent and pig hearts. Here we investigate the molecular mechanism underlying this physiological effect. We show with molecular dynamics simulations that the binding of dADP.Pi (dATP hydrolysis products) to myosin alters the structure and dynamics of the nucleotide binding pocket, myosin cleft conformation, and actin binding sites, which collectively yield a myosin conformation that we predict favors weak, electrostatic binding to actin. In vitro motility assays at high ionic strength were conducted to test this prediction and we found that dATP increased motility. These results highlight alterations to myosin that enhance cross-bridge formation and reveal a potential mechanism that may underlie dATP-induced improvements in cardiac function.
[Mh] Termos MeSH primário: Miosinas Cardíacas/química
Nucleotídeos de Desoxiadenina/química
Simulação de Dinâmica Molecular
[Mh] Termos MeSH secundário: Regulação Alostérica
Sítios de Ligação
Seres Humanos
Relação Estrutura-Atividade
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Deoxyadenine Nucleotides); EC 3.6.1.- (Cardiac Myosins)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170717
[Lr] Data última revisão:
170717
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170119
[St] Status:MEDLINE
[do] DOI:10.1002/pro.3121


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[PMID]:27916517
[Au] Autor:Cheng TC; Akey IV; Yuan S; Yu Z; Ludtke SJ; Akey CW
[Ad] Endereço:Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street, Boston, MA 02118, USA.
[Ti] Título:A Near-Atomic Structure of the Dark Apoptosome Provides Insight into Assembly and Activation.
[So] Source:Structure;25(1):40-52, 2017 Jan 03.
[Is] ISSN:1878-4186
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:In Drosophila, the Apaf-1-related killer (Dark) forms an apoptosome that activates procaspases. To investigate function, we have determined a near-atomic structure of Dark double rings using cryo-electron microscopy. We then built a nearly complete model of the apoptosome that includes 7- and 8-blade ß-propellers. We find that the preference for dATP during Dark assembly may be governed by Ser325, which is in close proximity to the 2' carbon of the deoxyribose ring. Interestingly, ß-propellers in V-shaped domains of the Dark apoptosome are more widely separated, relative to these features in the Apaf-1 apoptosome. This wider spacing may be responsible for the lack of cytochrome c binding to ß-propellers in the Dark apoptosome. Our structure also highlights the roles of two loss-of-function mutations that may block Dark assembly. Finally, the improved model provides a framework to understand apical procaspase activation in the intrinsic cell death pathway.
[Mh] Termos MeSH primário: Nucleotídeos de Desoxiadenina/metabolismo
Proteínas de Drosophila/química
Proteínas de Drosophila/metabolismo
Drosophila melanogaster/metabolismo
Mutação
[Mh] Termos MeSH secundário: Animais
Apoptose
Apoptossomas/química
Apoptossomas/metabolismo
Caspases/metabolismo
Microscopia Crioeletrônica
Proteínas de Drosophila/genética
Drosophila melanogaster/química
Modelos Moleculares
Ligação Proteica
Conformação Proteica
Estrutura Secundária de Proteína
Serina/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Apoptosomes); 0 (Ark protein, Drosophila); 0 (Deoxyadenine Nucleotides); 0 (Drosophila Proteins); 452VLY9402 (Serine); EC 3.4.22.- (Caspases); K8KCC8SH6N (2'-deoxyadenosine triphosphate)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171018
[Lr] Data última revisão:
171018
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161206
[St] Status:MEDLINE


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[PMID]:27590227
[Au] Autor:Teichman SL; Thomson KS; Regnier M
[Ad] Endereço:BEAT Biotherapeutics Corp, 1380 112th Ave., NE, Suite 200, Seattle, WA, 98004, USA. steichman@beatbiotherapeutics.com.
[Ti] Título:Cardiac Myosin Activation with Gene Therapy Produces Sustained Inotropic Effects and May Treat Heart Failure with Reduced Ejection Fraction.
[So] Source:Handb Exp Pharmacol;243:447-464, 2017.
[Is] ISSN:0171-2004
[Cp] País de publicação:Germany
[La] Idioma:eng
[Ab] Resumo:Chronic inotropic therapy is effective for the treatment of heart failure with reduced ejection fraction, but has been limited by adverse long-term safety profiles, development of tolerance, and the need for chronic parenteral administration. A safe and convenient therapeutic agent that produces sustained inotropic effects could improve symptoms, functional capacity, and quality of life. Small amounts of 2-deoxy-adenosine triphosphate (dATP) activate cardiac myosin leading to enhanced contractility in normal and failing heart muscle. Cardiac myosin activation triggers faster myosin crossbridge cycling with greater force generation during each contraction. This paper describes the rationale and results of a translational medicine effort to increase dATP levels using a gene therapy strategy to deliver and upregulate ribonucleotide reductase (R1R2), the enzyme responsible for dATP synthesis, selectively in cardiomyocytes. In small and large animal models of heart failure, a single dose of this gene therapy has led to sustained inotropic effects with a benign safety profile. Further animal studies are appropriate with the goal of testing this agent in patients with heart failure.
[Mh] Termos MeSH primário: Miosinas Cardíacas/genética
Terapia Genética/métodos
Insuficiência Cardíaca/terapia
Contração Miocárdica/genética
Miocárdio/metabolismo
Volume Sistólico
[Mh] Termos MeSH secundário: Animais
Nucleotídeos de Desoxiadenina/metabolismo
Insuficiência Cardíaca/metabolismo
Insuficiência Cardíaca/fisiopatologia
Seres Humanos
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Nm] Nome de substância:
0 (Deoxyadenine Nucleotides); EC 3.6.1.- (Cardiac Myosins); K8KCC8SH6N (2'-deoxyadenosine triphosphate)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171024
[Lr] Data última revisão:
171024
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160904
[St] Status:MEDLINE
[do] DOI:10.1007/164_2016_31


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[PMID]:27557296
[Au] Autor:Chen X; McAllister KJ; Klein B; Bushman LR; Anderson PL
[Ad] Endereço:University of Colorado, Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO, USA.
[Ti] Título:Development and validation of an LC-MS/MS quantitative method for endogenous deoxynucleoside triphosphates in cellular lysate.
[So] Source:Biomed Chromatogr;31(3), 2017 Mar.
[Is] ISSN:1099-0801
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The endogenous deoxynucleoside triphosphate (dNTP) pool includes deoxyadenosine triphosphate (dATP), deoxycytidine triphosphate (dCTP), deoxyguanosine triphosphate (dGTP) and thymidine triphosphate (TTP). The endogenous dNTP pool is regulated by complex enzymatic pathways that can be targeted by drugs, such as antimetabolites. In addition, these components compete with antiviral nucleos(t)ide analog triphosphates, contributing to the mechanism of pharmacologic action. This communication describes the development and validation of a sensitive method to quantify the intracellular dNTP pool in cellular lysates. The extraction process was optimized for dNTPs using an indirect strategy - the separation of mono-, di- and triphosphate moieties by strong anion exchange, dephosphorylation of target fractions to molar equivalent nucleosides - followed by sensitive quantitation using liquid chromatography-tandem mass spectrometry. The validated analytical range was 50-2500 fmol/sample for each dNTP. The assay was used to quantify dNTPs in peripheral blood mononuclear cells from 40 clinical research participants (n = 279 samples). Median (interquartile range) concentrations were 143 (116, 169) for dATP, 737 (605, 887) for dCTP, 237 (200, 290) for dGTP and 315 (220, 456) for TTP, in femtomoles per million cells. This method allows for future studies of endogenous dNTP disposition in subjects receiving antimetabolites or nucleos(t)ide analogs, or for other clinical scenarios.
[Mh] Termos MeSH primário: Cromatografia Líquida/métodos
Nucleotídeos de Desoxiadenina/análise
Nucleotídeos de Desoxicitosina/análise
Espectrometria de Massas em Tandem/métodos
Nucleotídeos de Timina/análise
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Deoxyadenine Nucleotides); 0 (Deoxycytosine Nucleotides); 0 (Thymine Nucleotides); 2056-98-6 (2'-deoxycytidine 5'-triphosphate); K8KCC8SH6N (2'-deoxyadenosine triphosphate); QOP4K539MU (thymidine 5'-triphosphate)
[Em] Mês de entrada:1703
[Cu] Atualização por classe:170308
[Lr] Data última revisão:
170308
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160825
[St] Status:MEDLINE
[do] DOI:10.1002/bmc.3820


  9 / 1042 MEDLINE  
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[PMID]:27832147
[Au] Autor:Chen X; Seifert SM; Castillo-Mancilla JR; Bushman LR; Zheng JH; Kiser JJ; MaWhinney S; Anderson PL
[Ad] Endereço:University of Colorado, Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO, United States of America.
[Ti] Título:Model Linking Plasma and Intracellular Tenofovir/Emtricitabine with Deoxynucleoside Triphosphates.
[So] Source:PLoS One;11(11):e0165505, 2016.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The coformulation of the nucleos(t)ide analogs (NA) tenofovir (TFV) disoproxil fumarate (TDF) and emtricitabine (FTC) is approved for HIV-infection treatment and prevention. Plasma TFV and FTC undergo complicated hybrid processes to form, accumulate, and retain as their active intracellular anabolites: TFV-diphosphate (TFV-DP) and FTC-triphosphate (FTC-TP). Such complexities manifest in nonlinear intracellular pharmacokinetics (PK). In target cells, TFV-DP/FTC-TP compete with endogenous deoxynucleoside triphosphates (dNTP) at the active site of HIV reverse transcriptase, underscoring the importance of analog:dNTP ratios for antiviral efficacy. However, NA such as TFV and FTC have the potential to disturb the dNTP pool, which could augment or reduce their efficacies. We conducted a pharmacokinetics-pharmacodynamics (PKPD) study among forty subjects receiving daily TDF/FTC (300 mg/200 mg) from the first-dose to pharmacological intracellular steady-state (30 days). TFV/FTC in plasma, TFV-DP/FTC-TP and dNTPs in peripheral blood mononuclear cells (PBMC) were quantified using validated LC/MS/MS methodologies. Concentration-time data were analyzed using nonlinear mixed effects modeling (NONMEM). Formations and the accumulation of intracellular TFV-DP/FTC-TP was driven by plasma TFV/FTC, which was described by a hybrid of first-order formation and saturation. An indirect response link model described the interplay between TFV-DP/FTC-TP and the dNTP pool change. The EC50 (interindividual variability, (%CV)) of TFV-DP and FTC-TP on the inhibition of deoxyadenosine triphosphate (dATP) and deoxycytidine triphosphate (dCTP) production were 1020 fmol/106 cells (130%) and 44.4 pmol/106 cells (82.5%), resulting in (90% prediction interval) 11% (0.45%, 53%) and 14% (2.6%, 35%) reductions. Model simulations of analog:dNTP molar ratios using IPERGAY dosing suggested that FTC significantly contributes to the protective effect of preexposure prophylaxis (PrEP). Simulation-based intracellular operational multiple dosing half-lives of TFV-DP and FTC-TP were 6.7 days and 33 hours. This model described the formation of intracellular TFV-DP/FTC-TP and the interaction with dNTPs, and can be used to simulate analog:dNTP time course for various dosing strategies.
[Mh] Termos MeSH primário: Fármacos Anti-HIV/farmacologia
Fármacos Anti-HIV/farmacocinética
Nucleotídeos de Desoxiadenina/metabolismo
Nucleotídeos de Desoxicitosina/metabolismo
Emtricitabina/farmacologia
Emtricitabina/farmacocinética
Tenofovir/farmacologia
Tenofovir/farmacocinética
[Mh] Termos MeSH secundário: Adulto
Fármacos Anti-HIV/sangue
Fármacos Anti-HIV/metabolismo
Simulação por Computador
Difosfatos/metabolismo
Emtricitabina/sangue
Emtricitabina/metabolismo
Feminino
HIV/efeitos dos fármacos
Infecções por HIV/tratamento farmacológico
Seres Humanos
Masculino
Meia-Idade
Modelos Biológicos
Polifosfatos/metabolismo
Estudos Prospectivos
Tenofovir/sangue
Tenofovir/metabolismo
Adulto Jovem
[Pt] Tipo de publicação:JOURNAL ARTICLE; OBSERVATIONAL STUDY
[Nm] Nome de substância:
0 (2'-deoxyadenosine-3'-triphosphate); 0 (Anti-HIV Agents); 0 (Deoxyadenine Nucleotides); 0 (Deoxycytosine Nucleotides); 0 (Diphosphates); 0 (Polyphosphates); 69383-05-7 (3'-deoxycytidine 5'-triphosphate); 99YXE507IL (Tenofovir); G70B4ETF4S (Emtricitabine); NU43IAG5BC (triphosphoric acid)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170626
[Lr] Data última revisão:
170626
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161111
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0165505


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[PMID]:27618147
[Au] Autor:Nguyen VN; Park A; Xu A; Srouji JR; Brenner SE; Kirsch JF
[Ad] Endereço:Molecular and Cell Biology Department, University of California, Berkeley, California, 94720.
[Ti] Título:Substrate specificity characterization for eight putative nudix hydrolases. Evaluation of criteria for substrate identification within the Nudix family.
[So] Source:Proteins;84(12):1810-1822, 2016 Dec.
[Is] ISSN:1097-0134
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The nearly 50,000 known Nudix proteins have a diverse array of functions, of which the most extensively studied is the catalyzed hydrolysis of aberrant nucleotide triphosphates. The functions of 171 Nudix proteins have been characterized to some degree, although physiological relevance of the assayed activities has not always been conclusively demonstrated. We investigated substrate specificity for eight structurally characterized Nudix proteins, whose functions were unknown. These proteins were screened for hydrolase activity against a 74-compound library of known Nudix enzyme substrates. We found substrates for four enzymes with k /K values >10,000 M s : Q92EH0_LISIN of Listeria innocua serovar 6a against ADP-ribose, Q5LBB1_BACFN of Bacillus fragilis against 5-Me-CTP, and Q0TTC5_CLOP1 and Q0TS82_CLOP1 of Clostridium perfringens against 8-oxo-dATP and 3'-dGTP, respectively. To ascertain whether these identified substrates were physiologically relevant, we surveyed all reported Nudix hydrolytic activities against NTPs. Twenty-two Nudix enzymes are reported to have activity against canonical NTPs. With a single exception, we find that the reported k /K values exhibited against these canonical substrates are well under 10 M s . By contrast, several Nudix enzymes show much larger k /K values (in the range of 10 to >10 M s ) against noncanonical NTPs. We therefore conclude that hydrolytic activities exhibited by these enzymes against canonical NTPs are not likely their physiological function, but rather the result of unavoidable collateral damage occasioned by the enzymes' inability to distinguish completely between similar substrate structures. Proteins 2016; 84:1810-1822. © 2016 Wiley Periodicals, Inc.
[Mh] Termos MeSH primário: Proteínas de Bactérias/química
Fosfatos de Dinucleosídeos/química
Pirofosfatases/química
[Mh] Termos MeSH secundário: Adenosina Difosfato Ribose/química
Adenosina Difosfato Ribose/metabolismo
Bacillus/química
Bacillus/enzimologia
Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Clonagem Molecular
Clostridium perfringens/química
Clostridium perfringens/enzimologia
Nucleotídeos de Desoxiadenina/química
Nucleotídeos de Desoxiadenina/metabolismo
Nucleotídeos de Desoxiguanina/química
Nucleotídeos de Desoxiguanina/metabolismo
Fosfatos de Dinucleosídeos/metabolismo
Escherichia coli/genética
Escherichia coli/metabolismo
Expressão Gênica
Cinética
Listeria/química
Listeria/enzimologia
Família Multigênica
Pirofosfatases/genética
Pirofosfatases/metabolismo
Proteínas Recombinantes/química
Proteínas Recombinantes/genética
Proteínas Recombinantes/metabolismo
Especificidade por Substrato
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (8-oxodeoxyadenosine triphosphate); 0 (Bacterial Proteins); 0 (Deoxyadenine Nucleotides); 0 (Deoxyguanine Nucleotides); 0 (Dinucleoside Phosphates); 0 (Recombinant Proteins); 20762-30-5 (Adenosine Diphosphate Ribose); 8C2O37Y44Q (deoxyguanosine triphosphate); EC 3.6.1.- (Pyrophosphatases); EC 3.6.1.- (nudix hydrolases)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170609
[Lr] Data última revisão:
170609
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160913
[St] Status:MEDLINE
[do] DOI:10.1002/prot.25163



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