Remdesivir is one nucleotide analogue prodrug capable to terminate RNA synthesis in SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) by two distinct mechanisms. Although the "delayed chain termination" mechanism has been extensively investigated, the "template-dependent" inhibitory mechanism remains elusive. In this study, we have demonstrated that remdesivir embedded in the template strand seldom directly disrupted the complementary NTP incorporation at the active site. Instead, the translocation of remdesivir from the +2 to the +1 site was hindered due to the steric clash with V557. Moreover, we have elucidated the molecular mechanism characterizing the drug resistance upon V557L mutation. Overall, our studies have provided valuable insight into the "template-dependent" inhibitory mechanism exerted by remdesivir on SARS-CoV-2 RdRp and paved venues for an alternative antiviral strategy for the COVID-19 pandemic. As the "template-dependent" inhibition occurs across diverse viral RdRps, our findings may also shed light on a common acting mechanism of inhibitors.
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http://dx.doi.org/10.1021/acs.jpclett.2c01314 | DOI Listing |
Nucleic Acids Res
July 2024
Department of Chemistry and Biochemistry, Baylor University, Waco, TX 76798-7348, USA.
The replicative helicase, DnaB, is a central component of the replisome and unwinds duplex DNA coupled with immediate template-dependent DNA synthesis by the polymerase, Pol III. The rate of helicase unwinding is dynamically regulated through structural transitions in the DnaB hexamer between dilated and constricted states. Site-specific mutations in DnaB enforce a faster more constricted conformation that dysregulates unwinding dynamics, causing replisome decoupling that generates excess ssDNA and induces severe cellular stress.
View Article and Find Full Text PDFAnal Chem
November 2022
Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610065, P. R. China.
The template-dependent DNA synthesis, with DNA polymerases, templates, and primers, is essential for disease detection, molecular biology, and biotechnology. However, DNA polymerases can also initiate DNA synthesis without templates and primers, forming byproduct DNAs with random sequences. Herein, we report the mechanisms of the DNA synthesis in the absence or presence of nickase by discovering the reduced bindings between the polymerases and modified dNTPs and between the nickases and the modified DNAs and finding the reduced polymerase synthesis and nickase cleavage.
View Article and Find Full Text PDFNucleic Acids Res
September 2022
Department of Life Sciences, National Central University, Zhongli District, Taoyuan 320317, Taiwan.
tRNAHis guanylyltransferase (Thg1) catalyzes the 3'-5' incorporation of guanosine into position -1 (G-1) of tRNAHis. G-1 is unique to tRNAHis and is crucial for recognition by histidyl-tRNA synthetase (HisRS). Yeast Thg1 requires ATP for G-1 addition to tRNAHis opposite A73, whereas archaeal Thg1 requires either ATP or GTP for G-1 addition to tRNAHis opposite C73.
View Article and Find Full Text PDFJ Phys Chem Lett
August 2022
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 350002 Fuzhou, Fujian, China.
Remdesivir is one nucleotide analogue prodrug capable to terminate RNA synthesis in SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) by two distinct mechanisms. Although the "delayed chain termination" mechanism has been extensively investigated, the "template-dependent" inhibitory mechanism remains elusive. In this study, we have demonstrated that remdesivir embedded in the template strand seldom directly disrupted the complementary NTP incorporation at the active site.
View Article and Find Full Text PDFSci Transl Med
August 2022
Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
The nucleoside analog remdesivir (RDV) is a Food and Drug Administration-approved antiviral for treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Thus, it is critical to understand factors that promote or prevent RDV resistance. We passaged SARS-CoV-2 in the presence of increasing concentrations of GS-441524, the parent nucleoside of RDV.
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