1
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Rechkoblit O, Sciaky D, Kreitler DF, Buku A, Kottur J, Aggarwal AK. Activation of CBASS Cap5 endonuclease immune effector by cyclic nucleotides. Nat Struct Mol Biol 2024:10.1038/s41594-024-01220-x. [PMID: 38321146 DOI: 10.1038/s41594-024-01220-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 01/08/2024] [Indexed: 02/08/2024]
Abstract
The bacterial cyclic oligonucleotide-based antiphage signaling system (CBASS) is similar to the cGAS-STING system in humans, containing an enzyme that synthesizes a cyclic nucleotide on viral infection and an effector that senses the second messenger for the antiviral response. Cap5, containing a SAVED domain coupled to an HNH DNA endonuclease domain, is the most abundant CBASS effector, yet the mechanism by which it becomes activated for cell killing remains unknown. We present here high-resolution structures of full-length Cap5 from Pseudomonas syringae (Ps) with second messengers. The key to PsCap5 activation is a dimer-to-tetramer transition, whereby the binding of second messenger to dimer triggers an open-to-closed transformation of the SAVED domains, furnishing a surface for assembly of the tetramer. This movement propagates to the HNH domains, juxtaposing and converting two HNH domains into states for DNA destruction. These results show how Cap5 effects bacterial cell suicide and we provide proof-in-principle data that the CBASS can be extrinsically activated to limit bacterial infections.
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Affiliation(s)
- Olga Rechkoblit
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Daniela Sciaky
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Dale F Kreitler
- Center for BioMolecular Structure NSLS‑II, Brookhaven National Laboratory, Upton, NY, USA
| | - Angeliki Buku
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jithesh Kottur
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Antiviral Research, Institute of Advanced Virology, Thiruvananthapuram, India
| | - Aneel K Aggarwal
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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2
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Quintana-Feliciano R, Kottur J, Ni M, Ghosh R, Salas-Estrada L, Rechkoblit O, Filizola M, Fang G, Aggarwal AK. Burkholderia cenocepacia epigenetic regulator M.BceJIV simultaneously engages two DNA recognition sequences for methylation. bioRxiv 2024:2024.01.20.576384. [PMID: 38328099 PMCID: PMC10849533 DOI: 10.1101/2024.01.20.576384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Burkholderia cenocepacia is an opportunistic and infective bacterium containing an orphan DNA methyltransferase (M.BceJIV) with roles in regulating gene expression and motility of the bacterium. M.BceJIV recognizes a GTWWAC motif (where W can be an adenine or a thymine) and methylates the N6 of the adenine at the fifth base position (GTWWAC). Here, we present a high-resolution crystal structure of M.BceJIV/DNA/sinefungin ternary complex and allied biochemical, computational, and thermodynamic analyses. Remarkably, the structure shows not one, but two DNA substrates bound to the M.BceJIV dimer, wherein each monomer contributes to the recognition of two recognition sequences. This unexpected mode of DNA binding and methylation has not been observed previously and sets a new precedent for a DNA methyltransferase. We also show that methylation at two recognition sequences occurs independently, and that GTWWAC motifs are enriched in intergenic regions of a strain of B. cenocepacia's genome. We further computationally assess the interactions underlying the affinities of different ligands (SAM, SAH, and sinefungin) for M.BceJIV, as a step towards developing selective inhibitors for limiting B. cenocepacia infection.
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Affiliation(s)
- Richard Quintana-Feliciano
- Department of Pharmacological Sciences Icahn School of Medicine at Mount Sinai 1425 Madison Avenue New York, New York, USA
| | - Jithesh Kottur
- Department of Pharmacological Sciences Icahn School of Medicine at Mount Sinai 1425 Madison Avenue New York, New York, USA
| | - Mi Ni
- Department of Genetics and Genomic Sciences Icahn School of Medicine at Mount Sinai 1425 Madison Avenue New York, New York, USA
| | - Rikhia Ghosh
- Department of Pharmacological Sciences Icahn School of Medicine at Mount Sinai 1425 Madison Avenue New York, New York, USA
| | - Leslie Salas-Estrada
- Department of Pharmacological Sciences Icahn School of Medicine at Mount Sinai 1425 Madison Avenue New York, New York, USA
| | - Olga Rechkoblit
- Department of Pharmacological Sciences Icahn School of Medicine at Mount Sinai 1425 Madison Avenue New York, New York, USA
| | - Marta Filizola
- Department of Pharmacological Sciences Icahn School of Medicine at Mount Sinai 1425 Madison Avenue New York, New York, USA
| | - Gang Fang
- Department of Genetics and Genomic Sciences Icahn School of Medicine at Mount Sinai 1425 Madison Avenue New York, New York, USA
| | - Aneel K. Aggarwal
- Department of Pharmacological Sciences Icahn School of Medicine at Mount Sinai 1425 Madison Avenue New York, New York, USA
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3
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Yu X, Li D, Kottur J, Kim HS, Herring LE, Yu Y, Xie L, Hu X, Chen X, Cai L, Liu J, Aggarwal AK, Wang GG, Jin J. Discovery of Potent and Selective WDR5 Proteolysis Targeting Chimeras as Potential Therapeutics for Pancreatic Cancer. J Med Chem 2023; 66:16168-16186. [PMID: 38019706 PMCID: PMC10872723 DOI: 10.1021/acs.jmedchem.3c01521] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
As a core chromatin-regulatory scaffolding protein, WDR5 mediates numerous protein-protein interactions (PPIs) with other partner oncoproteins. However, small-molecule inhibitors that block these PPIs exert limited cell-killing effects. Here, we report structure-activity relationship studies in pancreatic ductal adenocarcinoma (PDAC) cells that led to the discovery of several WDR5 proteolysis-targeting chimer (PROTAC) degraders, including 11 (MS132), a highly potent and selective von Hippel-Lindau (VHL)-recruiting WDR5 degrader, which displayed positive binding cooperativity between WDR5 and VHL, effectively inhibited proliferation in PDAC cells, and was bioavailable in mice and 25, a cereblon (CRBN)-recruiting WDR5 degrader, which selectively degraded WDR5 over the CRBN neo-substrate IKZF1. Furthermore, by conducting site-directed mutagenesis studies, we determined that WDR5 K296, but not K32, was involved in the PROTAC-induced WDR5 degradation. Collectively, these studies resulted in a highly effective WDR5 degrader, which could be a potential therapeutic for pancreatic cancer and several potentially useful tool compounds.
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Affiliation(s)
- Xufen Yu
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
- Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Dongxu Li
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina 27599, United States
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Jithesh Kottur
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
- Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Huen Suk Kim
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
- Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Laura E Herring
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina 27599, United States
| | - Yao Yu
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina 27599, United States
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Duke Cancer Institute, Duke University School of Medicine, Durham, North Carolina 27710, United States
- Department of Pathology, Duke University School of Medicine, Durham, North Carolina 27710, United States
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina 27710, United States
| | - Ling Xie
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Xiaoping Hu
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
- Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Xian Chen
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Ling Cai
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina 27599, United States
- Duke Cancer Institute, Duke University School of Medicine, Durham, North Carolina 27710, United States
- Department of Pathology, Duke University School of Medicine, Durham, North Carolina 27710, United States
| | - Jing Liu
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
- Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Aneel K Aggarwal
- Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Gang Greg Wang
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina 27599, United States
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina 27599, United States
- Duke Cancer Institute, Duke University School of Medicine, Durham, North Carolina 27710, United States
- Department of Pathology, Duke University School of Medicine, Durham, North Carolina 27710, United States
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina 27710, United States
| | - Jian Jin
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
- Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
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4
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Abstract
The continual pressure of invading DNA has led bacteria to develop numerous immune systems, including a short prokaryotic Argonaute (pAgo) TIR-APAZ system (SPARTA) that is activated by invading DNA to unleash its TIR domain for NAD(P)+ hydrolysis. To gain a molecular understanding of this activation process, we resolved a crystal structure of SPARTA heterodimer in the absence of guide RNA/target ssDNA at 2.66Å resolution and a cryo-EM structure of the SPARTA oligomer (tetramer of heterodimers) bound to guide RNA/target ssDNA at nominal 3.15-3.35Å resolution. The crystal structure provides a high-resolution view of the TIR-APAZ protein and the MID-PIWI domains of short pAgo - wherein, the APAZ domain emerges as equivalent to the N, L1 and L2 regions of long pAgos and the MID domain has a unique insertion (insert57). A comparison to cryo-EM structure reveals regions of the PIWI (loop10-9) and APAZ (helix αN) domains that reconfigure to relieve auto-inhibition to permit nucleic acid binding and transition to an active oligomer. Oligomerization is accompanied by the nucleation of the TIR domains in a parallel-strands arrangement for catalysis. Together, the structures provide a visualization of SPARTA before and after RNA/ssDNA binding and reveal the basis of SPARTA's active assembly leading to NAD(P)+ degradation and abortive infection.
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Affiliation(s)
- Jithesh Kottur
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Radhika Malik
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Aneel K. Aggarwal
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
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5
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Kottur J, White KM, Rodriguez ML, Rechkoblit O, Quintana-Feliciano R, Nayar A, García-Sastre A, Aggarwal AK. Structures of SARS-CoV-2 N7-methyltransferase with DOT1L and PRMT7 inhibitors provide a platform for new antivirals. PLoS Pathog 2023; 19:e1011546. [PMID: 37523415 PMCID: PMC10414583 DOI: 10.1371/journal.ppat.1011546] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 08/10/2023] [Accepted: 07/06/2023] [Indexed: 08/02/2023] Open
Abstract
The RNA N7-methyltransferase (MTase) activity of SARS-CoV-2's nsp14 protein is essential for viral replication and is a target for the development of new antivirals. Nsp14 uses S-adenosyl methionine (SAM) as the methyl donor to cap the 5' end of the SARS-CoV-2 mRNA and generates S-adenosyl homocysteine (SAH) as the reaction byproduct. Due to the central role of histone MTases in cancer, many SAM/SAH analogs with properties of cell permeability have recently been developed for the inhibition of these MTases. We have succeeded in identifying two such compounds (SGC0946 and SGC8158) that display significant antiviral activity and bind to the SARS-CoV-2 nsp14 N7-MTase core. Unexpectedly, crystal structures of SGC0946 and SGC8158 with the SARS-CoV-2 nsp14 N7-MTase core identify them as bi-substrate inhibitors of the viral MTase, co-occupying both the SAM and RNA binding sites; positing novel features that can be derivatized for increased potency and selectivity for SARS-CoV-2 nsp14. Taken together, the high-resolution structures and the accompanying biophysical and viral replication data provide a new avenue for developing analogs of SGC0946 and SGC8158 as antivirals.
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Affiliation(s)
- Jithesh Kottur
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Kris M. White
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - M. Luis Rodriguez
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Olga Rechkoblit
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Richard Quintana-Feliciano
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Ahana Nayar
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- The Tisch Institute, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- Department of Pathology, Molecular and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Aneel K. Aggarwal
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
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6
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Li D, Yu X, Kottur J, Gong W, Zhang Z, Storey AJ, Tsai YH, Uryu H, Shen Y, Byrum SD, Edmondson RD, Mackintosh SG, Cai L, Liu Z, Aggarwal AK, Tackett AJ, Liu J, Jin J, Wang GG. Discovery of a dual WDR5 and Ikaros PROTAC degrader as an anti-cancer therapeutic. Oncogene 2022; 41:3328-3340. [PMID: 35525905 PMCID: PMC9189076 DOI: 10.1038/s41388-022-02340-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 12/21/2022]
Abstract
WD repeat domain 5 (WDR5), an integral component of the MLL/KMT2A lysine methyltransferase complex, is critically involved in oncogenesis and represents an attractive onco-target. Inhibitors targeting protein-protein interactions (PPIs) between WDR5 and its binding partners, however, do not inhibit all of WDR5-mediated oncogenic functions and exert rather limited antitumor effects. Here, we report a cereblon (CRBN)-recruiting proteolysis targeting chimera (PROTAC) of WDR5, MS40, which selectively degrades WDR5 and the well-established neo-substrates of immunomodulatory drugs (IMiDs):CRBN, the Ikaros zinc finger (IKZF) transcription factors IKZF1 and IKZF3. MS40-induced WDR5 degradation caused disassociation of the MLL/KMT2A complex off chromatin, resulting in decreased H3K4me2. Transcriptomic profiling revealed that targets of both WDR5 and IMiDs:CRBN were significantly repressed by treatment of MS40. In MLL-rearranged leukemias, which exhibit IKZF1 high expression and dependency, co-suppression of WDR5 and Ikaros by MS40 is superior in suppressing oncogenesis to the WDR5 PPI inhibitor, to MS40's non-PROTAC analog controls (MS40N1 and MS40N2, which do not bind CRBN and WDR5, respectively), and to a matched VHL-based WDR5 PROTAC (MS169, which degrades WDR5 but not Ikaros). MS40 suppressed the growth of primary leukemia patient cells in vitro and patient-derived xenografts in vivo. Thus, dual degradation of WDR5 and Ikaros is a promising anti-cancer strategy.
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Affiliation(s)
- Dongxu Li
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Xufen Yu
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jithesh Kottur
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Weida Gong
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Zhao Zhang
- Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Aaron J Storey
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Yi-Hsuan Tsai
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Hidetaka Uryu
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Yudao Shen
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Stephanie D Byrum
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Rick D Edmondson
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Samuel G Mackintosh
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Ling Cai
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Zhijie Liu
- Department of Molecular Medicine, Mays Cancer Center, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Aneel K Aggarwal
- Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Alan J Tackett
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Jing Liu
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jian Jin
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, USA. .,Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Gang Greg Wang
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. .,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. .,Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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7
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Aggarwal A, Kottur J. High resolution structures of the SARS-CoV-2 N7-methyltransferase inform therapeutic development.. [PMID: 35291302 PMCID: PMC8923114 DOI: 10.21203/rs.3.rs-1370473/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Emergence of SARS-CoV-2 coronavirus has led to millions of deaths globally. We present three high-resolution crystal structures of the SARS-CoV-2 nsp14 N7-methyltransferase core bound to S-adenosylmethionine (SAM; 1.62Å), S-adenosylhomocysteine (SAH; 1.55Å) and Sinefungin (SFG; 1.41Å). We identify features of the methyltransferase core that are crucial for the development of antivirals and show SAH as the best scaffold for the design of antivirals against SARS-CoV-2 and other pathogenic coronaviruses.
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8
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Yu X, Li D, Kottur J, Shen Y, Kim HS, Park KS, Tsai YH, Gong W, Wang J, Suzuki K, Parker J, Herring L, Kaniskan HÜ, Cai L, Jain R, Liu J, Aggarwal AK, Wang GG, Jin J. A selective WDR5 degrader inhibits acute myeloid leukemia in patient-derived mouse models. Sci Transl Med 2021; 13:eabj1578. [PMID: 34586829 PMCID: PMC8500670 DOI: 10.1126/scitranslmed.abj1578] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Interactions between WD40 repeat domain protein 5 (WDR5) and its various partners such as mixed lineage leukemia (MLL) and c-MYC are essential for sustaining oncogenesis in human cancers. However, inhibitors that block protein-protein interactions (PPIs) between WDR5 and its binding partners exhibit modest cancer cell killing effects and lack in vivo efficacy. Here, we present pharmacological degradation of WDR5 as a promising therapeutic strategy for treating WDR5-dependent tumors and report two high-resolution crystal structures of WDR5-degrader-E3 ligase ternary complexes. We identified an effective WDR5 degrader via structure-based design and demonstrated its in vitro and in vivo antitumor activities. On the basis of the crystal structure of an initial WDR5 degrader in complex with WDR5 and the E3 ligase von Hippel–Lindau (VHL), we designed a WDR5 degrader, MS67, and demonstrated the high cooperativity of MS67 binding to WDR5 and VHL by another ternary complex structure and biophysical characterization. MS67 potently and selectively depleted WDR5 and was more effective than WDR5 PPI inhibitors in suppressing transcription of WDR5-regulated genes, decreasing the chromatin-bound fraction of MLL complex components and c-MYC, and inhibiting the proliferation of cancer cells. In addition, MS67 suppressed malignant growth of MLL-rearranged acute myeloid leukemia patient cells in vitro and in vivo and was well tolerated in vivo. Collectively, our results demonstrate that structure-based design can be an effective strategy to identify highly active degraders and suggest that pharmacological degradation of WDR5 might be a promising treatment for WDR5-dependent cancers.
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Affiliation(s)
- Xufen Yu
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.,Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Dongxu Li
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jithesh Kottur
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.,Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Yudao Shen
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.,Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Huen Suk Kim
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.,Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Kwang-Su Park
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.,Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Yi-Hsuan Tsai
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Weida Gong
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jun Wang
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Kyogo Suzuki
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Joel Parker
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Laura Herring
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - H. Ümit Kaniskan
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.,Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ling Cai
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Rinku Jain
- Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jing Liu
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.,Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Aneel K Aggarwal
- Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Gang Greg Wang
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Corresponding author. (J.J.); (G.G.W.)
| | - Jian Jin
- Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.,Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.,Corresponding author. (J.J.); (G.G.W.)
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9
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Johnson MK, Kottur J, Nair DT. A polar filter in DNA polymerases prevents ribonucleotide incorporation. Nucleic Acids Res 2020; 47:10693-10705. [PMID: 31544946 PMCID: PMC6846668 DOI: 10.1093/nar/gkz792] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 09/02/2019] [Accepted: 09/09/2019] [Indexed: 12/17/2022] Open
Abstract
The presence of ribonucleotides in DNA can lead to genomic instability and cellular lethality. To prevent adventitious rNTP incorporation, the majority of the DNA polymerases (dPols) possess a steric filter. The dPol named MsDpo4 (Mycobacterium smegmatis) naturally lacks this steric filter and hence is capable of rNTP addition. The introduction of the steric filter in MsDpo4 did not result in complete abrogation of the ability of this enzyme to incorporate ribonucleotides. In comparison, DNA polymerase IV (PolIV) from Escherichia coli exhibited stringent selection for deoxyribonucleotides. A comparison of MsDpo4 and PolIV led to the discovery of an additional polar filter responsible for sugar selectivity. Thr43 represents the filter in PolIV and this residue forms interactions with the incoming nucleotide to draw it closer to the enzyme surface. As a result, the 2’-OH in rNTPs will clash with the enzyme surface, and therefore ribonucleotides cannot be accommodated in the active site in a conformation compatible with productive catalysis. The substitution of the equivalent residue in MsDpo4–Cys47, with Thr led to a drastic reduction in the ability of the mycobacterial enzyme to incorporate rNTPs. Overall, our studies evince that the polar filter serves to prevent ribonucleotide incorporation by dPols.
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Affiliation(s)
- Mary K Johnson
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India.,National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bangalore 560065, India
| | - Jithesh Kottur
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
| | - Deepak T Nair
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121001, India
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10
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Kottur J, Nair DT. Pyrophosphate hydrolysis is an intrinsic and critical step of the DNA synthesis reaction. Nucleic Acids Res 2019; 46:5875-5885. [PMID: 29850882 PMCID: PMC6159520 DOI: 10.1093/nar/gky402] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 05/15/2018] [Indexed: 11/14/2022] Open
Abstract
DNA synthesis by DNA polymerases (dPols) is central to duplication and maintenance of the genome in all living organisms. dPols catalyze the formation of a phosphodiester bond between the incoming deoxynucleoside triphosphate and the terminal primer nucleotide with the release of a pyrophosphate (PPi) group. It is believed that formation of the phosphodiester bond is an endergonic reaction and PPi has to be hydrolyzed by accompanying pyrophosphatase enzymes to ensure that the free energy change of the DNA synthesis reaction is negative and it can proceed in the forward direction. The fact that DNA synthesis proceeds in vitro in the absence of pyrophosphatases represents a long-standing conundrum regarding the thermodynamics of the DNA synthesis reaction. Using time-resolved crystallography, we show that hydrolysis of PPi is an intrinsic and critical step of the DNA synthesis reaction catalyzed by dPols. The hydrolysis of PPi occurs after the formation of the phosphodiester bond and ensures that the DNA synthesis reaction is energetically favorable without the need for additional enzymes. Also, we observe that DNA synthesis is a two Mg2+ ion assisted stepwise associative SN2 reaction. Overall, this study provides deep temporal insight regarding the primary enzymatic reaction responsible for genome duplication.
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Affiliation(s)
- Jithesh Kottur
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121 001, India
| | - Deepak T Nair
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad 121 001, India
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11
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Kottur J, Nair DT. Reactive Oxygen Species Play an Important Role in the Bactericidal Activity of Quinolone Antibiotics. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201509340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Jithesh Kottur
- Regional Centre for Biotechnology; NCR Biotech Science Cluster; 3rd Milestone, Faridabad-Gurgaon Expressway Faridabad 121001 India
- Manipal University, Madhav Nagar; Manipal 576104 India
| | - Deepak T. Nair
- Regional Centre for Biotechnology; NCR Biotech Science Cluster; 3rd Milestone, Faridabad-Gurgaon Expressway Faridabad 121001 India
- National Centre for Biological Sciences, NCBS-TIFR, GKVK Campus; Bangalore 560065 India
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12
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Kottur J, Nair DT. Reactive Oxygen Species Play an Important Role in the Bactericidal Activity of Quinolone Antibiotics. Angew Chem Int Ed Engl 2016; 55:2397-400. [PMID: 26757158 DOI: 10.1002/anie.201509340] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 11/23/2015] [Indexed: 11/10/2022]
Abstract
Recent studies posit that reactive oxygen species (ROS) contribute to the cell lethality of bactericidal antibiotics. However, this conjecture has been challenged and remains controversial. To resolve this controversy, we adopted a strategy that involves DNA polymerase IV (PolIV). The nucleotide pool of the cell gets oxidized by ROS and PolIV incorporates the damaged nucleotides (especially 8oxodGTP) into the genome, which results in death of the bacteria. By using a combination of structural and biochemical tools coupled with growth assays, it was shown that selective perturbation of the 8oxodGTP incorporation activity of PolIV results in considerable enhancement of the survival of bacteria in the presence of the norfloxacin antibiotic. Our studies therefore indicate that ROS induced in bacteria by the presence of antibiotics in the environment contribute significantly to cell lethality.
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Affiliation(s)
- Jithesh Kottur
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, India.,Manipal University, Madhav Nagar, Manipal, 576104, India
| | - Deepak T Nair
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad, 121001, India. .,National Centre for Biological Sciences, NCBS-TIFR, GKVK Campus, Bangalore, 560065, India.
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13
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Ghodke PP, Gore KR, Harikrishna S, Samanta B, Kottur J, Nair DT, Pradeepkumar PI. The N(2)-Furfuryl-deoxyguanosine Adduct Does Not Alter the Structure of B-DNA. J Org Chem 2016; 81:502-11. [PMID: 26650891 DOI: 10.1021/acs.joc.5b02341] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
N(2)-Furfuryl-deoxyguanosine (fdG) is carcinogenic DNA adduct that originates from furfuryl alcohol. It is also a stable structural mimic of the damage induced by the nitrofurazone family of antibiotics. For the structural and functional studies of this model N(2)-dG adduct, reliable and rapid access to fdG-modified DNAs are warranted. Toward this end, here we report the synthesis of fdG-modified DNAs using phosphoramidite chemistry involving only three steps. The functional integrity of the modified DNA has been verified by primer extension studies with DNA polymerases I and IV from E. coli. Introduction of fdG into a DNA duplex decreases the Tm by ∼1.6 °C/modification. Molecular dynamics simulations of a DNA duplex bearing the fdG adduct revealed that though the overall B-DNA structure is maintained, this lesion can disrupt W-C H-bonding, stacking interactions, and minor groove hydrations to some extent at the modified site, and these effects lead to slight variations in the local base pair parameters. Overall, our studies show that fdG is tolerated at the minor groove of the DNA to a better extent compared with other bulky DNA damages, and this property will make it difficult for the DNA repair pathways to detect this adduct.
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Affiliation(s)
- Pratibha P Ghodke
- Department of Chemistry, Indian Institute of Technology Bombay , Mumbai-400076, India
| | - Kiran R Gore
- Department of Chemistry, Indian Institute of Technology Bombay , Mumbai-400076, India.,Department of Chemistry, University of Mumbai , Mumbai-400098, India
| | - S Harikrishna
- Department of Chemistry, Indian Institute of Technology Bombay , Mumbai-400076, India
| | - Biswajit Samanta
- Department of Chemistry, Indian Institute of Technology Bombay , Mumbai-400076, India
| | - Jithesh Kottur
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Third Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, India.,Manipal University, Manipal-576104, India
| | - Deepak T Nair
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Third Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, India.,National Centre for Biological Sciences (NCBS-TIFR), GKVK Campus, Bellary Road, Bangalore-560065, India
| | - P I Pradeepkumar
- Department of Chemistry, Indian Institute of Technology Bombay , Mumbai-400076, India
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14
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Nair DT, Kottur J, Sharma R. A rescue act: Translesion DNA synthesis past N(2) -deoxyguanosine adducts. IUBMB Life 2015; 67:564-74. [PMID: 26173005 DOI: 10.1002/iub.1403] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 06/17/2015] [Indexed: 01/14/2023]
Abstract
Genomic DNA is continually subjected to a number of chemical insults that result in the formation of modified nucleotides--termed as DNA lesions. The N(2) -atom of deoxyguanosine is particularly reactive and a number of chemicals react at this site to form different kinds of DNA adducts. The N(2) -deoxyguanosine adducts perturb different genomic processes and are particularly deleterious for DNA replication as they have a strong tendency to inhibit replicative DNA polymerases. Many organisms possess specialized dPols--generally classified in the Y-family--that serves to rescue replication stalled at N(2) -dG and other adducts. A review of minor groove N(2) -adducts and the known strategies utilized by Y-family dPols to replicate past these lesions will be presented here.
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Affiliation(s)
- Deepak T Nair
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, 121 001, India
| | - Jithesh Kottur
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, 121 001, India.,Manipal University, Manipal.Edu, Manipal, 576104, Karnataka, India
| | - Rahul Sharma
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, 121 001, India.,Manipal University, Manipal.Edu, Manipal, 576104, Karnataka, India
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15
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Weinert T, Olieric V, Waltersperger S, Panepucci E, Chen L, Zhang H, Zhou D, Rose J, Ebihara A, Kuramitsu S, Li D, Howe N, Schnapp G, Pautsch A, Bargsten K, Prota AE, Surana P, Kottur J, Nair DT, Basilico F, Cecatiello V, Pasqualato S, Boland A, Weichenrieder O, Wang BC, Steinmetz MO, Caffrey M, Wang M. Erratum: Corrigendum: Fast native-SAD phasing for routine macromolecular structure determination. Nat Methods 2015. [DOI: 10.1038/nmeth0715-692a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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Kottur J, Sharma A, Gore KR, Narayanan N, Samanta B, Pradeepkumar PI, Nair DT. Unique structural features in DNA polymerase IV enable efficient bypass of the N2 adduct induced by the nitrofurazone antibiotic. Structure 2014; 23:56-67. [PMID: 25497730 DOI: 10.1016/j.str.2014.10.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 10/27/2014] [Accepted: 10/28/2014] [Indexed: 11/17/2022]
Abstract
The reduction in the efficacy of therapeutic antibiotics represents a global problem of increasing intensity and concern. Nitrofuran antibiotics act primarily through the formation of covalent adducts at the N(2) atom of the deoxyguanosine nucleotide in genomic DNA. These adducts inhibit replicative DNA polymerases (dPols), leading to the death of the prokaryote. N(2)-furfuryl-deoxyguanosine (fdG) represents a stable structural analog of the nitrofuran-induced adducts. Unlike other known dPols, DNA polymerase IV (PolIV) from E. coli can bypass the fdG adduct accurately with high catalytic efficiency. This property of PolIV is central to its role in reducing the sensitivity of E. coli toward nitrofuran antibiotics such as nitrofurazone (NFZ). We present the mechanism used by PolIV to bypass NFZ-induced adducts and thus improve viability of E. coli in the presence of NFZ. Our results can be used to develop specific inhibitors of PolIV that may potentiate the activity of nitrofuran antibiotics.
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Affiliation(s)
- Jithesh Kottur
- National Centre for Biological Sciences (NCBS-TIFR), GKVK Campus, Bellary Road, Bangalore 560065, India; Manipal University, Manipal.edu, Madhav Nagar, Manipal 576104, India
| | - Amit Sharma
- National Centre for Biological Sciences (NCBS-TIFR), GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Kiran R Gore
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Naveen Narayanan
- National Centre for Biological Sciences (NCBS-TIFR), GKVK Campus, Bellary Road, Bangalore 560065, India; Manipal University, Manipal.edu, Madhav Nagar, Manipal 576104, India
| | - Biswajit Samanta
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | | | - Deepak T Nair
- Regional Centre for Biotechnology, 180, Udyog Vihar, Phase 1, Gurgaon 122016, India; National Centre for Biological Sciences (NCBS-TIFR), GKVK Campus, Bellary Road, Bangalore 560065, India.
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17
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Sharma A, Kottur J, Narayanan N, Nair DT. A strategically located serine residue is critical for the mutator activity of DNA polymerase IV from Escherichia coli. Nucleic Acids Res 2013; 41:5104-14. [PMID: 23525461 PMCID: PMC3643571 DOI: 10.1093/nar/gkt146] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The Y-family DNA polymerase IV or PolIV (Escherichia coli) is the founding member of the DinB family and is known to play an important role in stress-induced mutagenesis. We have determined four crystal structures of this enzyme in its pre-catalytic state in complex with substrate DNA presenting the four possible template nucleotides that are paired with the corresponding incoming nucleotide triphosphates. In all four structures, the Ser42 residue in the active site forms interactions with the base moieties of the incipient Watson–Crick base pair. This residue is located close to the centre of the nascent base pair towards the minor groove. In vitro and in vivo assays show that the fidelity of the PolIV enzyme increases drastically when this Ser residue was mutated to Ala. In addition, the structure of PolIV with the mismatch A:C in the active site shows that the Ser42 residue plays an important role in stabilizing dCTP in a conformation compatible with catalysis. Overall, the structural, biochemical and functional data presented here show that the Ser42 residue is present at a strategic location to stabilize mismatches in the PolIV active site, and thus facilitate the appearance of transition and transversion mutations.
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Affiliation(s)
- Amit Sharma
- National Centre for Biological Sciences (NCBS-TIFR), UAS-GKVK Campus, Bellary Road, Bangalore 560065, India
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