The Experts below are selected from a list of 26643 Experts worldwide ranked by ideXlab platform
Matthias Götte - One of the best experts on this subject based on the ideXlab platform.
-
the antiviral compound remdesivir potently inhibits rna dependent rna polymerase from middle east respiratory syndrome coronavirus
Journal of Biological Chemistry, 2020Co-Authors: Calvin J Gordon, Egor P. Tchesnokov, Danielle P Porter, Joy Y Feng, Matthias GötteAbstract:Antiviral drugs for managing infections with human coronaviruses are not yet approved, posing a serious challenge to current global efforts aimed at containing the outbreak of severe acute respiratory syndrome-coronavirus 2 (CoV-2). Remdesivir (RDV) is an investigational compound with a broad spectrum of antiviral activities against RNA viruses, including severe acute respiratory syndrome-CoV and Middle East respiratory syndrome (MERS-CoV). RDV is a nucleotide analog inhibitor of RNA-dependent RNA polymerases (RdRps). Here, we co-expressed the MERS-CoV nonstructural proteins nsp5, nsp7, nsp8, and nsp12 (RdRp) in insect cells as a part a polyprotein to study the mechanism of inhibition of MERS-CoV RdRp by RDV. We initially demonstrated that nsp8 and nsp12 form an active complex. The triphosphate form of the inhibitor (RDV-TP) competes with its natural counterpart ATP. Of note, the Selectivity Value for RDV-TP obtained here with a steady-state approach suggests that it is more efficiently incorporated than ATP and two other nucleotide analogs. Once incorporated at position i, the inhibitor caused RNA synthesis arrest at position i + 3. Hence, the likely mechanism of action is delayed RNA chain termination. The additional three nucleotides may protect the inhibitor from excision by the viral 3'-5' exonuclease activity. Together, these results help to explain the high potency of RDV against RNA viruses in cell-based assays.
-
Mechanism of Inhibition of Ebola Virus RNA-Dependent RNA Polymerase by Remdesivir
Viruses, 2019Co-Authors: Egor P. Tchesnokov, Danielle Porter, Joy Y Feng, Matthias GötteAbstract:Remdesivir (GS-5734) is a 1′-cyano-substituted adenosine nucleotide analogue prodrug that shows broad-spectrum antiviral activity against several RNA viruses. This compound is currently under clinical development for the treatment of Ebola virus disease (EVD). While antiviral effects have been demonstrated in cell culture and in non-human primates, the mechanism of action of Ebola virus (EBOV) inhibition for remdesivir remains to be fully elucidated. The EBOV RNA-dependent RNA polymerase (RdRp) complex was recently expressed and purified, enabling biochemical studies with the relevant triphosphate (TP) form of remdesivir and its presumptive target. In this study, we confirmed that remdesivir-TP is able to compete for incorporation with adenosine triphosphate (ATP). Enzyme kinetics revealed that EBOV RdRp and respiratory syncytial virus (RSV) RdRp incorporate ATP and remdesivir-TP with similar efficiencies. The Selectivity of ATP against remdesivir-TP is ~4 for EBOV RdRp and ~3 for RSV RdRp. In contrast, purified human mitochondrial RNA polymerase (h-mtRNAP) effectively discriminates against remdesivir-TP with a Selectivity Value of ~500-fold. For EBOV RdRp, the incorporated inhibitor at position i does not affect the ensuing nucleotide incorporation event at position i+1. For RSV RdRp, we measured a ~6-fold inhibition at position i+1 although RNA synthesis was not terminated. Chain termination was in both cases delayed and was seen predominantly at position i+5. This pattern is specific to remdesivir-TP and its 1′-cyano modification. Compounds with modifications at the 2′-position show different patterns of inhibition. While 2′-C-methyl-ATP is not incorporated, ara-ATP acts as a non-obligate chain terminator and prevents nucleotide incorporation at position i+1. Taken together, our biochemical data indicate that the major contribution to EBOV RNA synthesis inhibition by remdesivir can be ascribed to delayed chain termination. The long distance of five residues between the incorporated nucleotide analogue and its inhibitory effect warrant further investigation.
Egor P. Tchesnokov - One of the best experts on this subject based on the ideXlab platform.
-
the antiviral compound remdesivir potently inhibits rna dependent rna polymerase from middle east respiratory syndrome coronavirus
Journal of Biological Chemistry, 2020Co-Authors: Calvin J Gordon, Egor P. Tchesnokov, Danielle P Porter, Joy Y Feng, Matthias GötteAbstract:Antiviral drugs for managing infections with human coronaviruses are not yet approved, posing a serious challenge to current global efforts aimed at containing the outbreak of severe acute respiratory syndrome-coronavirus 2 (CoV-2). Remdesivir (RDV) is an investigational compound with a broad spectrum of antiviral activities against RNA viruses, including severe acute respiratory syndrome-CoV and Middle East respiratory syndrome (MERS-CoV). RDV is a nucleotide analog inhibitor of RNA-dependent RNA polymerases (RdRps). Here, we co-expressed the MERS-CoV nonstructural proteins nsp5, nsp7, nsp8, and nsp12 (RdRp) in insect cells as a part a polyprotein to study the mechanism of inhibition of MERS-CoV RdRp by RDV. We initially demonstrated that nsp8 and nsp12 form an active complex. The triphosphate form of the inhibitor (RDV-TP) competes with its natural counterpart ATP. Of note, the Selectivity Value for RDV-TP obtained here with a steady-state approach suggests that it is more efficiently incorporated than ATP and two other nucleotide analogs. Once incorporated at position i, the inhibitor caused RNA synthesis arrest at position i + 3. Hence, the likely mechanism of action is delayed RNA chain termination. The additional three nucleotides may protect the inhibitor from excision by the viral 3'-5' exonuclease activity. Together, these results help to explain the high potency of RDV against RNA viruses in cell-based assays.
-
Mechanism of Inhibition of Ebola Virus RNA-Dependent RNA Polymerase by Remdesivir
Viruses, 2019Co-Authors: Egor P. Tchesnokov, Danielle Porter, Joy Y Feng, Matthias GötteAbstract:Remdesivir (GS-5734) is a 1′-cyano-substituted adenosine nucleotide analogue prodrug that shows broad-spectrum antiviral activity against several RNA viruses. This compound is currently under clinical development for the treatment of Ebola virus disease (EVD). While antiviral effects have been demonstrated in cell culture and in non-human primates, the mechanism of action of Ebola virus (EBOV) inhibition for remdesivir remains to be fully elucidated. The EBOV RNA-dependent RNA polymerase (RdRp) complex was recently expressed and purified, enabling biochemical studies with the relevant triphosphate (TP) form of remdesivir and its presumptive target. In this study, we confirmed that remdesivir-TP is able to compete for incorporation with adenosine triphosphate (ATP). Enzyme kinetics revealed that EBOV RdRp and respiratory syncytial virus (RSV) RdRp incorporate ATP and remdesivir-TP with similar efficiencies. The Selectivity of ATP against remdesivir-TP is ~4 for EBOV RdRp and ~3 for RSV RdRp. In contrast, purified human mitochondrial RNA polymerase (h-mtRNAP) effectively discriminates against remdesivir-TP with a Selectivity Value of ~500-fold. For EBOV RdRp, the incorporated inhibitor at position i does not affect the ensuing nucleotide incorporation event at position i+1. For RSV RdRp, we measured a ~6-fold inhibition at position i+1 although RNA synthesis was not terminated. Chain termination was in both cases delayed and was seen predominantly at position i+5. This pattern is specific to remdesivir-TP and its 1′-cyano modification. Compounds with modifications at the 2′-position show different patterns of inhibition. While 2′-C-methyl-ATP is not incorporated, ara-ATP acts as a non-obligate chain terminator and prevents nucleotide incorporation at position i+1. Taken together, our biochemical data indicate that the major contribution to EBOV RNA synthesis inhibition by remdesivir can be ascribed to delayed chain termination. The long distance of five residues between the incorporated nucleotide analogue and its inhibitory effect warrant further investigation.
Joy Y Feng - One of the best experts on this subject based on the ideXlab platform.
-
the antiviral compound remdesivir potently inhibits rna dependent rna polymerase from middle east respiratory syndrome coronavirus
Journal of Biological Chemistry, 2020Co-Authors: Calvin J Gordon, Egor P. Tchesnokov, Danielle P Porter, Joy Y Feng, Matthias GötteAbstract:Antiviral drugs for managing infections with human coronaviruses are not yet approved, posing a serious challenge to current global efforts aimed at containing the outbreak of severe acute respiratory syndrome-coronavirus 2 (CoV-2). Remdesivir (RDV) is an investigational compound with a broad spectrum of antiviral activities against RNA viruses, including severe acute respiratory syndrome-CoV and Middle East respiratory syndrome (MERS-CoV). RDV is a nucleotide analog inhibitor of RNA-dependent RNA polymerases (RdRps). Here, we co-expressed the MERS-CoV nonstructural proteins nsp5, nsp7, nsp8, and nsp12 (RdRp) in insect cells as a part a polyprotein to study the mechanism of inhibition of MERS-CoV RdRp by RDV. We initially demonstrated that nsp8 and nsp12 form an active complex. The triphosphate form of the inhibitor (RDV-TP) competes with its natural counterpart ATP. Of note, the Selectivity Value for RDV-TP obtained here with a steady-state approach suggests that it is more efficiently incorporated than ATP and two other nucleotide analogs. Once incorporated at position i, the inhibitor caused RNA synthesis arrest at position i + 3. Hence, the likely mechanism of action is delayed RNA chain termination. The additional three nucleotides may protect the inhibitor from excision by the viral 3'-5' exonuclease activity. Together, these results help to explain the high potency of RDV against RNA viruses in cell-based assays.
-
Mechanism of Inhibition of Ebola Virus RNA-Dependent RNA Polymerase by Remdesivir
Viruses, 2019Co-Authors: Egor P. Tchesnokov, Danielle Porter, Joy Y Feng, Matthias GötteAbstract:Remdesivir (GS-5734) is a 1′-cyano-substituted adenosine nucleotide analogue prodrug that shows broad-spectrum antiviral activity against several RNA viruses. This compound is currently under clinical development for the treatment of Ebola virus disease (EVD). While antiviral effects have been demonstrated in cell culture and in non-human primates, the mechanism of action of Ebola virus (EBOV) inhibition for remdesivir remains to be fully elucidated. The EBOV RNA-dependent RNA polymerase (RdRp) complex was recently expressed and purified, enabling biochemical studies with the relevant triphosphate (TP) form of remdesivir and its presumptive target. In this study, we confirmed that remdesivir-TP is able to compete for incorporation with adenosine triphosphate (ATP). Enzyme kinetics revealed that EBOV RdRp and respiratory syncytial virus (RSV) RdRp incorporate ATP and remdesivir-TP with similar efficiencies. The Selectivity of ATP against remdesivir-TP is ~4 for EBOV RdRp and ~3 for RSV RdRp. In contrast, purified human mitochondrial RNA polymerase (h-mtRNAP) effectively discriminates against remdesivir-TP with a Selectivity Value of ~500-fold. For EBOV RdRp, the incorporated inhibitor at position i does not affect the ensuing nucleotide incorporation event at position i+1. For RSV RdRp, we measured a ~6-fold inhibition at position i+1 although RNA synthesis was not terminated. Chain termination was in both cases delayed and was seen predominantly at position i+5. This pattern is specific to remdesivir-TP and its 1′-cyano modification. Compounds with modifications at the 2′-position show different patterns of inhibition. While 2′-C-methyl-ATP is not incorporated, ara-ATP acts as a non-obligate chain terminator and prevents nucleotide incorporation at position i+1. Taken together, our biochemical data indicate that the major contribution to EBOV RNA synthesis inhibition by remdesivir can be ascribed to delayed chain termination. The long distance of five residues between the incorporated nucleotide analogue and its inhibitory effect warrant further investigation.
Calvin J Gordon - One of the best experts on this subject based on the ideXlab platform.
-
the antiviral compound remdesivir potently inhibits rna dependent rna polymerase from middle east respiratory syndrome coronavirus
Journal of Biological Chemistry, 2020Co-Authors: Calvin J Gordon, Egor P. Tchesnokov, Danielle P Porter, Joy Y Feng, Matthias GötteAbstract:Antiviral drugs for managing infections with human coronaviruses are not yet approved, posing a serious challenge to current global efforts aimed at containing the outbreak of severe acute respiratory syndrome-coronavirus 2 (CoV-2). Remdesivir (RDV) is an investigational compound with a broad spectrum of antiviral activities against RNA viruses, including severe acute respiratory syndrome-CoV and Middle East respiratory syndrome (MERS-CoV). RDV is a nucleotide analog inhibitor of RNA-dependent RNA polymerases (RdRps). Here, we co-expressed the MERS-CoV nonstructural proteins nsp5, nsp7, nsp8, and nsp12 (RdRp) in insect cells as a part a polyprotein to study the mechanism of inhibition of MERS-CoV RdRp by RDV. We initially demonstrated that nsp8 and nsp12 form an active complex. The triphosphate form of the inhibitor (RDV-TP) competes with its natural counterpart ATP. Of note, the Selectivity Value for RDV-TP obtained here with a steady-state approach suggests that it is more efficiently incorporated than ATP and two other nucleotide analogs. Once incorporated at position i, the inhibitor caused RNA synthesis arrest at position i + 3. Hence, the likely mechanism of action is delayed RNA chain termination. The additional three nucleotides may protect the inhibitor from excision by the viral 3'-5' exonuclease activity. Together, these results help to explain the high potency of RDV against RNA viruses in cell-based assays.
Shizhong Luo - One of the best experts on this subject based on the ideXlab platform.
-
synthesis and characterization of mesoporous v mcm 41 molecular sieves with good hydrothermal and thermal stability
Journal of Molecular Catalysis A-chemical, 2006Co-Authors: Wei Chu, Shizhong LuoAbstract:Abstract Stable V-MCM-41 mesoporous materials have been synthesized by hydrothermal method, using hexadecyl-trimethyl-ammonium bromide as template, and industrial Na2O·(3.3–3.5)SiO2 as the source of much cheaper silica instead of conventional expensive organic precursors. Several modern techniques like XRD, N2 adsorption, FT-IR, UV–vis and SEM have been utilized to characterize the framework structure and texture of the samples. The results of N2 adsorption and X-ray diffraction showed that the synthesized samples had a high ordered hexagonal structure, good hydrothermal stability and thermal stability. The selective oxidation of styrene using hydrogen peroxide as oxidant over V-MCM-41 samples showed a good catalytic performance of partial oxidation, the phenylacetic acid was the principal product (the Selectivity Value was 49.4%). Even after a thermal treatment at 900 °C in air for 12 h or a hydrothermal treatment in boiling water for 8 days, each of the two resultant materials could retain the ordered channels and a high BET surface area. UV–vis spectra provided strong evidences that most of vanadium ions were incorporated into the framework of siliceous MCM-41 sample.