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Chopra A, Bauman JD, Ruiz FX, Arnold E. Halo Library, a Tool for Rapid Identification of Ligand Binding Sites on Proteins Using Crystallographic Fragment Screening. J Med Chem 2023; 66:6013-6024. [PMID: 37115705 PMCID: PMC10184123 DOI: 10.1021/acs.jmedchem.2c01681] [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] [Indexed: 04/29/2023]
Abstract
X-ray crystallographic fragment screening (XCFS) uses fragment-sized molecules (∼60 to 300 Da) to access binding sites on proteins that may be inaccessible to larger drug-like molecules (>300 Da). Previous studies have shown that fragments containing halogen atoms bind more often to proteins than non-halogenated fragments. Here, we designed the Halo Library containing 46 halogenated fragments (including the "universal fragment" 4-bromopyrazole), a majority of which have been reported to bind to or inhibit one or more targets. The library was screened against the crystals of HIV-1 reverse transcriptase with the drug rilpivirine, yielding an overall hit rate of 26%. Two new binding sites were discovered, and several hot spots were identified. This small library may thus provide a convenient tool for rapidly assessing the feasibility of a target for XCFS, mapping hot spots and cryptic sites, as well as finding fragment binders that can be useful for developing drug leads.
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Affiliation(s)
- Ashima Chopra
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08854, United States
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Joseph D Bauman
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08854, United States
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Francesc X Ruiz
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08854, United States
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08854, United States
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
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2
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Mansouri M, Rumrill S, Dawson S, Johnson A, Pinson JA, Gunzburg MJ, Latham CF, Barlow N, Mbogo GW, Ellenberg P, Headey SJ, Sluis-Cremer N, Tyssen D, Bauman JD, Ruiz FX, Arnold E, Chalmers DK, Tachedjian G. Targeting HIV-1 Reverse Transcriptase Using a Fragment-Based Approach. Molecules 2023; 28:3103. [PMID: 37049868 PMCID: PMC10095864 DOI: 10.3390/molecules28073103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 03/24/2023] [Accepted: 03/24/2023] [Indexed: 04/03/2023] Open
Abstract
Human immunodeficiency virus type I (HIV-1) is a retrovirus that infects cells of the host's immune system leading to acquired immunodeficiency syndrome and potentially death. Although treatments are available to prevent its progression, HIV-1 remains a major burden on health resources worldwide. Continued emergence of drug-resistance mutations drives the need for novel drugs that can inhibit HIV-1 replication through new pathways. The viral protein reverse transcriptase (RT) plays a fundamental role in the HIV-1 replication cycle, and multiple approved medications target this enzyme. In this study, fragment-based drug discovery was used to optimize a previously identified hit fragment (compound B-1), which bound RT at a novel site. Three series of compounds were synthesized and evaluated for their HIV-1 RT binding and inhibition. These series were designed to investigate different vectors around the initial hit in an attempt to improve inhibitory activity against RT. Our results show that the 4-position of the core scaffold is important for binding of the fragment to RT, and a lead compound with a cyclopropyl substitution was selected and further investigated. Requirements for binding to the NNRTI-binding pocket (NNIBP) and a novel adjacent site were investigated, with lead compound 27-a minimal but efficient NNRTI-offering a starting site for the development of novel dual NNIBP-Adjacent site inhibitors.
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Affiliation(s)
- Mahta Mansouri
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Shawn Rumrill
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Shane Dawson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Adam Johnson
- Retroviral Biology and Antivirals Laboratory, Disease Elimination Program, Life Sciences Discipline, Burnet Institute, Melbourne, VIC 3004, Australia
| | - Jo-Anne Pinson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Menachem J. Gunzburg
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Catherine F. Latham
- Retroviral Biology and Antivirals Laboratory, Disease Elimination Program, Life Sciences Discipline, Burnet Institute, Melbourne, VIC 3004, Australia
| | - Nicholas Barlow
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - George W. Mbogo
- Retroviral Biology and Antivirals Laboratory, Disease Elimination Program, Life Sciences Discipline, Burnet Institute, Melbourne, VIC 3004, Australia
| | - Paula Ellenberg
- Retroviral Biology and Antivirals Laboratory, Disease Elimination Program, Life Sciences Discipline, Burnet Institute, Melbourne, VIC 3004, Australia
| | - Stephen J. Headey
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Nicolas Sluis-Cremer
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - David Tyssen
- Retroviral Biology and Antivirals Laboratory, Disease Elimination Program, Life Sciences Discipline, Burnet Institute, Melbourne, VIC 3004, Australia
| | - Joseph D. Bauman
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Francesc X. Ruiz
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - David K. Chalmers
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Gilda Tachedjian
- Retroviral Biology and Antivirals Laboratory, Disease Elimination Program, Life Sciences Discipline, Burnet Institute, Melbourne, VIC 3004, Australia
- Department of Microbiology, Monash University, Clayton, VIC 3168, Australia
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC 3000, Australia
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3
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Harrison JJEK, Passos DO, Bruhn JF, Bauman JD, Tuberty L, DeStefano JJ, Ruiz FX, Lyumkis D, Arnold E. Cryo-EM structure of the HIV-1 Pol polyprotein provides insights into virion maturation. Sci Adv 2022; 8:eabn9874. [PMID: 35857464 PMCID: PMC9258950 DOI: 10.1126/sciadv.abn9874] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 05/20/2022] [Indexed: 06/15/2023]
Abstract
Key proteins of retroviruses and other RNA viruses are translated and subsequently processed from polyprotein precursors by the viral protease (PR). Processing of the HIV Gag-Pol polyprotein yields the HIV structural proteins and enzymes. Structures of the mature enzymes PR, reverse transcriptase (RT), and integrase (IN) aided understanding of catalysis and design of antiretrovirals, but knowledge of the Pol precursor architecture and function before PR cleavage is limited. We developed a system to produce stable HIV-1 Pol and determined its cryo-electron microscopy structure. RT in Pol has a similar arrangement to the mature RT heterodimer, and its dimerization may draw together two PR monomers to activate proteolytic processing. HIV-1 thus may leverage the dimerization interfaces in Pol to regulate assembly and maturation of polyprotein precursors.
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Affiliation(s)
- Jerry Joe E. K. Harrison
- Center for Advanced Biotechnology and Medicine (CABM), Piscataway, NJ, USA
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, USA
- Department of Chemistry, University of Ghana, Legon, Ghana
| | | | - Jessica F. Bruhn
- The Salk Institute for Biological Studies, La Jolla, CA, USA
- NanoImaging Services, San Diego, CA, USA
| | - Joseph D. Bauman
- Center for Advanced Biotechnology and Medicine (CABM), Piscataway, NJ, USA
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, USA
| | - Lynda Tuberty
- Center for Advanced Biotechnology and Medicine (CABM), Piscataway, NJ, USA
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, USA
| | - Jeffrey J. DeStefano
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
- Maryland Pathogen Research Institute, University of Maryland, College Park, MD, USA
| | - Francesc Xavier Ruiz
- Center for Advanced Biotechnology and Medicine (CABM), Piscataway, NJ, USA
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, USA
| | - Dmitry Lyumkis
- The Salk Institute for Biological Studies, La Jolla, CA, USA
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine (CABM), Piscataway, NJ, USA
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, USA
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4
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Harrison JJEK, Tuske S, Das K, Ruiz FX, Bauman JD, Boyer PL, DeStefano JJ, Hughes SH, Arnold E. Crystal Structure of a Retroviral Polyprotein: Prototype Foamy Virus Protease-Reverse Transcriptase (PR-RT). Viruses 2021; 13:v13081495. [PMID: 34452360 PMCID: PMC8402755 DOI: 10.3390/v13081495] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/21/2021] [Accepted: 07/26/2021] [Indexed: 12/23/2022] Open
Abstract
In most cases, proteolytic processing of the retroviral Pol portion of the Gag-Pol polyprotein precursor produces protease (PR), reverse transcriptase (RT), and integrase (IN). However, foamy viruses (FVs) express Pol separately from Gag and, when Pol is processed, only the IN domain is released. Here, we report a 2.9 Å resolution crystal structure of the mature PR-RT from prototype FV (PFV) that can carry out both proteolytic processing and reverse transcription but is in a configuration not competent for proteolytic or polymerase activity. PFV PR-RT is monomeric and the architecture of PFV PR is similar to one of the subunits of HIV-1 PR, which is a dimer. There is a C-terminal extension of PFV PR (101-145) that consists of two helices which are adjacent to the base of the RT palm subdomain, and anchors PR to RT. The polymerase domain of PFV RT consists of fingers, palm, thumb, and connection subdomains whose spatial arrangements are similar to the p51 subunit of HIV-1 RT. The RNase H and polymerase domains of PFV RT are connected by flexible linkers. Significant spatial and conformational (sub)domain rearrangements are therefore required for nucleic acid binding. The structure of PFV PR-RT provides insights into the conformational maturation of retroviral Pol polyproteins.
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Affiliation(s)
- Jerry Joe E. K. Harrison
- Center for Advanced Biotechnology and Medicine (CABM), Rutgers University, Piscataway, NJ 08854, USA; (J.J.E.K.H.); (S.T.); (K.D.); (F.X.R.); (J.D.B.)
- Department of Medicinal Chemistry, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854, USA
- Department of Chemistry, University of Ghana, Legon P.O. Box LG 56, Ghana
| | - Steve Tuske
- Center for Advanced Biotechnology and Medicine (CABM), Rutgers University, Piscataway, NJ 08854, USA; (J.J.E.K.H.); (S.T.); (K.D.); (F.X.R.); (J.D.B.)
| | - Kalyan Das
- Center for Advanced Biotechnology and Medicine (CABM), Rutgers University, Piscataway, NJ 08854, USA; (J.J.E.K.H.); (S.T.); (K.D.); (F.X.R.); (J.D.B.)
- Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, 3000 Leuven, Belgium
| | - Francesc X. Ruiz
- Center for Advanced Biotechnology and Medicine (CABM), Rutgers University, Piscataway, NJ 08854, USA; (J.J.E.K.H.); (S.T.); (K.D.); (F.X.R.); (J.D.B.)
| | - Joseph D. Bauman
- Center for Advanced Biotechnology and Medicine (CABM), Rutgers University, Piscataway, NJ 08854, USA; (J.J.E.K.H.); (S.T.); (K.D.); (F.X.R.); (J.D.B.)
| | - Paul L. Boyer
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702, USA; (P.L.B.); (S.H.H.)
| | - Jeffrey J. DeStefano
- Department of Cell Biology and Molecular Genetics, University of Maryland College Park, College Park, MD 20742, USA;
| | - Stephen H. Hughes
- HIV Dynamics and Replication Program, National Cancer Institute, Frederick, MD 21702, USA; (P.L.B.); (S.H.H.)
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine (CABM), Rutgers University, Piscataway, NJ 08854, USA; (J.J.E.K.H.); (S.T.); (K.D.); (F.X.R.); (J.D.B.)
- Department of Medicinal Chemistry, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854, USA
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
- Correspondence:
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5
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Tuske S, Zheng J, Olson ED, Ruiz FX, Pascal BD, Hoang A, Bauman JD, Das K, DeStefano JJ, Musier-Forsyth K, Griffin PR, Arnold E. Integrative structural biology studies of HIV-1 reverse transcriptase binding to a high-affinity DNA aptamer. Curr Res Struct Biol 2020; 2:116-129. [PMID: 33870216 PMCID: PMC8052095 DOI: 10.1016/j.crstbi.2020.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/03/2020] [Accepted: 06/19/2020] [Indexed: 02/07/2023] Open
Abstract
The high-resolution crystal structure of HIV-1 reverse transcriptase (RT) bound to a 38-mer DNA hairpin aptamer with low pM affinity was previously described. The high-affinity binding aptamer contained 2'-O-methyl modifications and a seven base-pair GC-rich tract and the structure of the RT-aptamer complex revealed specific contacts between RT and the template strand of the aptamer. Similar to all crystal structures of RT bound to nucleic acid template-primers, the aptamer bound RT with a bend in the duplex DNA. To understand the structural basis for the ultra-high-affinity aptamer binding, an integrative structural biology approach was used. Hydrogen-deuterium exchange coupled to liquid chromatography-mass spectrometry (HDX-MS) was used to examine the structural dynamics of RT alone and in the presence of the DNA aptamer. RT was selectively labeled with 15N to unambiguously identify peptides from each subunit. HDX of unliganded RT shows a mostly stable core. The p66 fingers and thumb subdomains, and the RNase H domain are relatively dynamic. HDX indicates that both the aptamer and a scrambled version significantly stabilize regions of RT that are dynamic in the absence of DNA. No substantial differences in RT dynamics are observed between aptamer and scrambled aptamer binding, despite a large difference in binding affinity. Small-angle X-ray scattering and circular dichroism spectroscopy were used to investigate the aptamer conformation in solution and revealed a pre-bent DNA that possesses both A- and B-form helical character. Both the 2'-O-methyl modifications and the GC tract appear to contribute to an energetically favorable conformation for binding to RT that contributes to the aptamer's ultra-high affinity for RT. The X-ray structure of RT with an RNA/DNA version of the aptamer at 2.8 Å resolution revealed a potential role of the hairpin positioning in affinity. Together, the data suggest that both the 2'-O-methyl modifications and the GC tract contribute to an energetically favorable conformation for high-affinity binding to RT.
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Affiliation(s)
- Steve Tuske
- Center for Advanced Biotechnology and Medicine, And Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Jie Zheng
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | - Erik D. Olson
- Department of Chemistry and Biochemistry, Center for RNA Biology, And Center for Retrovirus Research, The Ohio State University, Columbus, OH, 43210, USA
| | - Francesc X. Ruiz
- Center for Advanced Biotechnology and Medicine, And Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Bruce D. Pascal
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | - Anthony Hoang
- Center for Advanced Biotechnology and Medicine, And Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Joseph D. Bauman
- Center for Advanced Biotechnology and Medicine, And Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Kalyan Das
- Center for Advanced Biotechnology and Medicine, And Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Jeffrey J. DeStefano
- Department of Cell Biology and Molecular Genetics, University of Maryland College Park, College Park, MD, 20740, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for RNA Biology, And Center for Retrovirus Research, The Ohio State University, Columbus, OH, 43210, USA
| | - Patrick R. Griffin
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL, 33458, USA
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine, And Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
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6
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Sagong HY, Bauman JD, Nogales A, Martínez-Sobrido L, Arnold E, LaVoie EJ. Aryl and Arylalkyl Substituted 3-Hydroxypyridin-2(1H)-ones: Synthesis and Evaluation as Inhibitors of Influenza A Endonuclease. ChemMedChem 2019; 14:1204-1223. [PMID: 30983160 PMCID: PMC6581572 DOI: 10.1002/cmdc.201900084] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 04/07/2019] [Indexed: 02/06/2023]
Abstract
Seasonal influenza infections are associated with an estimated 250-500 000 deaths annually. Resistance to the antiviral M2 ion-channel inhibitors has largely invalidated their clinical utility. Resistance to neuraminidase inhibitors has also been observed in several influenza A virus (IAV) strains. These data have prompted research on inhibitors that target the cap-snatching endonuclease activity of the polymerase acidic protein (PA). Baloxavir marboxil (Xofluza®), recently approved for clinical use, inhibits cap-snatching endonuclease. Resistance to Xofluza® has been reported in both in vitro systems and in the clinic. An X-ray crystallographic screening campaign of a fragment library targeting IAV endonuclease identified 5-chloro-3-hydroxypyridin-2(1H)-one as a bimetal chelating agent at the active site. We have reported the structure-activity relationships for 3-hydroxypyridin-2(1H)-ones and 3-hydroxyquinolin-2(1H)-ones as endonuclease inhibitors. These studies identified two distinct binding modes associated with inhibition of this enzyme that are influenced by the presence of substituents at the 5- and 6-positions of 3-hydroxypyridin-2(1H)-ones. Herein we report the structure-activity relationships associated with various para-substituted 5-phenyl derivatives of 6-(p-fluorophenyl)-3-hydroxypyridin-2(1H)-ones and the effect of using naphthyl, benzyl, and naphthylmethyl groups as alternatives to the p-fluorophenyl substituent on their activity as endonuclease inhibitors.
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Affiliation(s)
- Hye Yeon Sagong
- Department of Medicinal Chemistry, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ, 08854-8020, USA
| | - Joseph D Bauman
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Hoes Lane, Piscataway, NJ, 08854-5627, USA
| | - Aitor Nogales
- Department of Microbiology and Immunology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 672, Rochester, NY, 14642, USA
| | - Luis Martínez-Sobrido
- Department of Microbiology and Immunology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 672, Rochester, NY, 14642, USA
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Hoes Lane, Piscataway, NJ, 08854-5627, USA
| | - Edmond J LaVoie
- Department of Medicinal Chemistry, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ, 08854-8020, USA
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7
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Martinez SE, Bauman JD, Das K, Arnold E. Structure of HIV-1 reverse transcriptase/d4TTP complex: Novel DNA cross-linking site and pH-dependent conformational changes. Protein Sci 2018; 28:587-597. [PMID: 30499174 DOI: 10.1002/pro.3559] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/16/2018] [Accepted: 11/19/2018] [Indexed: 12/22/2022]
Abstract
Stavudine (d4T, 2',3'-didehydro-2',3'-dideoxythymidine) was one of the first chain-terminating nucleoside analogs used to treat HIV infection. We present the first structure of the active, triphosphate form of d4T (d4TTP) bound to a catalytic complex of HIV-1 RT/dsDNA template-primer. We also present a new strategy for disulfide (S-S) chemical cross-linking between N6 of a modified adenine at the second overhang base to I63C in the fingers subdomain of RT. The cross-link site is upstream of the duplex-binding region of RT, however, the structure is very similar to published RT structures with cross-linking to Q258C in the thumb, which suggests that cross-linking at either site does not appreciably perturb the RT/DNA structures. RT has a catalytic maximum at pH 7.5. We determined the X-ray structures of the I63C-RT/dsDNA/d4TTP cross-linked complexes at pH 7, 7.5, 8, 8.5, 9, and 9.5. We found small (~0.5 Å), pH-dependent motions of the fingers subdomain that folds in to form the dNTP-binding pocket. We propose that the pH-activity profile of RT relates to this motion of the fingers. Due to side effects of neuropathy and lipodystrophy, use of d4T has been stopped in most countries, however, chemical modification of d4T might lead to the development of a new class of nucleoside analogs targeting RNA and DNA polymerases.
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Affiliation(s)
- Sergio E Martinez
- Center for Advanced Biotechnology and Medicine, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854.,Rega Institute for Medical Research and Department of Microbiology and Immunology, KU Leuven, Leuven, 3000, Belgium
| | - Joseph D Bauman
- Center for Advanced Biotechnology and Medicine, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854
| | - Kalyan Das
- Rega Institute for Medical Research and Department of Microbiology and Immunology, KU Leuven, Leuven, 3000, Belgium
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854
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8
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Patel D, Antwi J, Koneru PC, Serrao E, Forli S, Kessl JJ, Feng L, Deng N, Levy RM, Fuchs JR, Olson AJ, Engelman AN, Bauman JD, Kvaratskhelia M, Arnold E. A New Class of Allosteric HIV-1 Integrase Inhibitors Identified by Crystallographic Fragment Screening of the Catalytic Core Domain. J Biol Chem 2016; 291:23569-23577. [PMID: 27645997 DOI: 10.1074/jbc.m116.753384] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Indexed: 12/29/2022] Open
Abstract
HIV-1 integrase (IN) is essential for virus replication and represents an important multifunctional therapeutic target. Recently discovered quinoline-based allosteric IN inhibitors (ALLINIs) potently impair HIV-1 replication and are currently in clinical trials. ALLINIs exhibit a multimodal mechanism of action by inducing aberrant IN multimerization during virion morphogenesis and by competing with IN for binding to its cognate cellular cofactor LEDGF/p75 during early steps of HIV-1 infection. However, quinoline-based ALLINIs impose a low genetic barrier for the evolution of resistant phenotypes, which highlights a need for discovery of second-generation inhibitors. Using crystallographic screening of a library of 971 fragments against the HIV-1 IN catalytic core domain (CCD) followed by a fragment expansion approach, we have identified thiophenecarboxylic acid derivatives that bind at the CCD-CCD dimer interface at the principal lens epithelium-derived growth factor (LEDGF)/p75 binding pocket. The most active derivative (5) inhibited LEDGF/p75-dependent HIV-1 IN activity in vitro with an IC50 of 72 μm and impaired HIV-1 infection of T cells at an EC50 of 36 μm The identified lead compound, with a relatively small molecular weight (221 Da), provides an optimal building block for developing a new class of inhibitors. Furthermore, although structurally distinct thiophenecarboxylic acid derivatives target a similar pocket at the IN dimer interface as the quinoline-based ALLINIs, the lead compound, 5, inhibited IN mutants that confer resistance to quinoline-based compounds. Collectively, our findings provide a plausible path for structure-based development of second-generation ALLINIs.
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Affiliation(s)
- Disha Patel
- From the Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08854
| | - Janet Antwi
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy and
| | - Pratibha C Koneru
- Center for Retrovirus Research and College of Pharmacy, Ohio State University, Columbus, Ohio 43210
| | - Erik Serrao
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215
| | - Stefano Forli
- Molecular Graphics Laboratory, Department of Integrative Structural and Computational Biology, MB-112, The Scripps Research Institute, La Jolla, California 92037
| | - Jacques J Kessl
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406, and
| | - Lei Feng
- Center for Retrovirus Research and College of Pharmacy, Ohio State University, Columbus, Ohio 43210
| | - Nanjie Deng
- Center for Biophysics and Computational Biology, Temple University, Philadelphia, Pennsylvania 19122
| | - Ronald M Levy
- Center for Biophysics and Computational Biology, Temple University, Philadelphia, Pennsylvania 19122
| | - James R Fuchs
- Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy and
| | - Arthur J Olson
- Molecular Graphics Laboratory, Department of Integrative Structural and Computational Biology, MB-112, The Scripps Research Institute, La Jolla, California 92037
| | - Alan N Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215
| | - Joseph D Bauman
- From the Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08854
| | - Mamuka Kvaratskhelia
- Center for Retrovirus Research and College of Pharmacy, Ohio State University, Columbus, Ohio 43210,
| | - Eddy Arnold
- From the Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08854,
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9
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Bauman JD, Harrison JJEK, Arnold E. Rapid experimental SAD phasing and hot-spot identification with halogenated fragments. IUCrJ 2016; 3:51-60. [PMID: 26870381 PMCID: PMC4704079 DOI: 10.1107/s2052252515021259] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 11/09/2015] [Indexed: 05/14/2023]
Abstract
Through X-ray crystallographic fragment screening, 4-bromopyrazole was discovered to be a 'magic bullet' that is capable of binding at many of the ligand 'hot spots' found in HIV-1 reverse transcriptase (RT). The binding locations can be in pockets that are 'hidden' in the unliganded crystal form, allowing rapid identification of these sites for in silico screening. In addition to hot-spot identification, this ubiquitous yet specific binding provides an avenue for X-ray crystallographic phase determination, which can be a significant bottleneck in the determination of the structures of novel proteins. The anomalous signal from 4-bromopyrazole or 4-iodopyrazole was sufficient to determine the structures of three proteins (HIV-1 RT, influenza A endonuclease and proteinase K) by single-wavelength anomalous dispersion (SAD) from single crystals. Both compounds are inexpensive, readily available, safe and very soluble in DMSO or water, allowing efficient soaking into crystals.
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Affiliation(s)
- Joseph D. Bauman
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, 679 Hoes Lane, Piscataway, NJ 08854, USA
| | - Jerry Joe E. K. Harrison
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, 679 Hoes Lane, Piscataway, NJ 08854, USA
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, 679 Hoes Lane, Piscataway, NJ 08854, USA
- Correspondence e-mail:
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10
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Goswami D, Tuske S, Pascal BD, Bauman JD, Patel D, Arnold E, Griffin PR. Differential isotopic enrichment to facilitate characterization of asymmetric multimeric proteins using hydrogen/deuterium exchange mass spectrometry. Anal Chem 2015; 87:4015-4022. [PMID: 25763479 DOI: 10.1021/acs.analchem.5b00372] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hydrogen/deuterium exchange (HDX) coupled to mass spectrometry has emerged as a powerful tool for analyzing the conformational dynamics of protein-ligand and protein-protein interactions. Recent advances in instrumentation and methodology have expanded the utility of HDX for the analysis of large and complex proteins; however, asymmetric dimers with shared amino acid sequence present a unique challenge for HDX because assignment of peptides with identical sequence to their subunit of origin remains ambiguous. Here we report the use of differential isotopic labeling to facilitate HDX analysis of multimers using HIV-1 reverse transcriptase (RT) as a model. RT is an asymmetric heterodimer of 51 kDa (p51) and 66 kDa (p66) subunits. The first 440 residues of p51 and p66 are identical. In this study differentially labeled RT was reconstituted from isotopically enriched ((15)N-labeled) p51 and unlabeled p66. To enable detection of (15)N-deuterated RT peptides, the software HDX Workbench was modified to follow a 100% (15)N model. Our results demonstrated that (15)N enrichment of p51 did not affect its conformational dynamics compared to unlabeled p51, but (15)N-labeled p51 did show different conformational dynamics than p66 in the RT heterodimer. Differential HDX-MS of isotopically labeled RT in the presence of the non-nucleoside reverse transcriptase inhibitor (NNRTI) efavirenz (EFV) showed subunit-specific perturbation in the rate of HDX consistent with previously published results and the RT-EFV cocrystal structure.
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Affiliation(s)
- Devrishi Goswami
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458.USA
| | - Steve Tuske
- Center for Advanced Biotechnology and Medicine, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Bruce D Pascal
- Informatics Core, The Scripps Research Institute, Jupiter, FL 33458.USA
| | - Joseph D Bauman
- Center for Advanced Biotechnology and Medicine, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Disha Patel
- Center for Advanced Biotechnology and Medicine, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Patrick R Griffin
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458.USA
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11
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Bauman JD, Patel D, Baker SF, Vijayan RSK, Xiang A, Parhi AK, Martínez-Sobrido L, LaVoie EJ, Das K, Arnold E. Crystallographic fragment screening and structure-based optimization yields a new class of influenza endonuclease inhibitors. ACS Chem Biol 2013; 8:2501-8. [PMID: 23978130 PMCID: PMC3928712 DOI: 10.1021/cb400400j] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [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: 12/20/2022]
Abstract
Seasonal and pandemic influenza viruses continue to be a leading global health concern. Emerging resistance to the current drugs and the variable efficacy of vaccines underscore the need for developing new flu drugs that will be broadly effective against wild-type and drug-resistant influenza strains. Here, we report the discovery and development of a class of inhibitors targeting the cap-snatching endonuclease activity of the viral polymerase. A high-resolution crystal form of pandemic 2009 H1N1 influenza polymerase acidic protein N-terminal endonuclease domain (PAN) was engineered and used for fragment screening leading to the identification of new chemical scaffolds binding to the PAN active site cleft. During the course of screening, binding of a third metal ion that is potentially relevant to endonuclease activity was detected in the active site cleft of PAN in the presence of a fragment. Using structure-based optimization, we developed a highly potent hydroxypyridinone series of compounds from a fragment hit that defines a new mode of chelation to the active site metal ions. A compound from the series demonstrating promising enzymatic inhibition in a fluorescence-based enzyme assay with an IC50 value of 11 nM was found to have an antiviral activity (EC50) of 11 μM against PR8 H1N1 influenza A in MDCK cells.
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Affiliation(s)
- Joseph D. Bauman
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08854, USA
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Disha Patel
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08854, USA
- Department of Medicinal Chemistry, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Steven F. Baker
- Department of Microbiology and Immunology, University of Rochester, Rochester, New York 14642, USA
| | - R. S. K. Vijayan
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Amy Xiang
- TAXIS Pharmaceuticals Inc., North Brunswick, New Jersey 08902, USA
| | - Ajit K. Parhi
- Department of Medicinal Chemistry, Rutgers University, Piscataway, New Jersey 08854, USA
- TAXIS Pharmaceuticals Inc., North Brunswick, New Jersey 08902, USA
| | - Luis Martínez-Sobrido
- Department of Microbiology and Immunology, University of Rochester, Rochester, New York 14642, USA
| | - Edmond J. LaVoie
- Department of Medicinal Chemistry, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Kalyan Das
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08854, USA
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08854, USA
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA
- Department of Medicinal Chemistry, Rutgers University, Piscataway, New Jersey 08854, USA
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12
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Bollini M, Frey KM, Cisneros JA, Spasov KA, Das K, Bauman JD, Arnold E, Anderson KS, Jorgensen WL. Extension into the entrance channel of HIV-1 reverse transcriptase--crystallography and enhanced solubility. Bioorg Med Chem Lett 2013; 23:5209-12. [PMID: 23899617 DOI: 10.1016/j.bmcl.2013.06.093] [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] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 06/21/2013] [Accepted: 06/27/2013] [Indexed: 01/15/2023]
Abstract
Non-nucleoside inhibitors of HIV-1 reverse transcriptase (HIV-RT) are reported that feature extension into the entrance channel near Glu138. Complexes of the parent anilinylpyrimidine 1 and the morpholinoethoxy analog 2j with HIV-RT have received crystallographic characterization confirming the designs. Measurement of aqueous solubilities of 2j, 2k, the parent triazene 2a, and other NNRTIs demonstrate profound benefits for addition of the morpholinyl substituent.
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Affiliation(s)
- Mariela Bollini
- Department of Chemistry, Yale University, New Haven, CT 06520-8107, USA
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13
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Sagong HY, Parhi A, Bauman JD, Patel D, Vijayan RSK, Das K, Arnold E, LaVoie EJ. 3-Hydroxyquinolin-2(1H)-ones As Inhibitors of Influenza A Endonuclease. ACS Med Chem Lett 2013; 4:547-50. [PMID: 24936242 DOI: 10.1021/ml4001112] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 05/07/2013] [Indexed: 11/29/2022] Open
Abstract
Several 3-hydroxyquinolin-2(1H)-ones derivatives were synthesized and evaluated as inhibitors of 2009 pandemic H1N1 influenza A endonuclease. All five of the monobrominated 3-hydroxyquinolin(1H)-2-ones derivatives were synthesized. Suzuki-coupling of p-fluorophenylboronic acid with each of these brominated derivatives provided the respective p-fluorophenyl 3-hydroxyquinolin(1H)-2-ones. In addition to 3-hydroxyquinolin-2(1H)-one, its 4-methyl, 4-phenyl, 4-methyl-7-(p-fluorophenyl), and 4-phenyl-7-(p-fluorophenyl) derivatives were also synthesized. Comparative studies on their relative activity revealed that both 6- and 7-(p-fluorophenyl)-3-hydroxyquinolin-2(1H)-one are among the more potent inhibitors of H1N1 influenza A endonuclease. An X-ray crystal structure of 7-(p-fluorophenyl)-3-hydroxyquinolin-2(1H)-one complexed to the influenza endonuclease revealed that this molecule chelates to two metal ions at the active site of the enzyme.
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Affiliation(s)
- Hye Yeon Sagong
- Department of Medicinal Chemistry,
Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854-8020, United
States
| | - Ajit Parhi
- Department of Medicinal Chemistry,
Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854-8020, United
States
| | - Joseph D. Bauman
- Center for Advanced
Biotechnology
and Medicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854-5627,
United States
| | - Disha Patel
- Department of Medicinal Chemistry,
Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854-8020, United
States
| | - R. S. K. Vijayan
- Center for Advanced
Biotechnology
and Medicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854-5627,
United States
| | - Kalyan Das
- Center for Advanced
Biotechnology
and Medicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854-5627,
United States
| | - Eddy Arnold
- Center for Advanced
Biotechnology
and Medicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854-5627,
United States
| | - Edmond J. LaVoie
- Department of Medicinal Chemistry,
Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854-8020, United
States
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14
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Bauman JD, Patel D, Dharia C, Fromer MW, Ahmed S, Frenkel Y, Vijayan RSK, Eck JT, Ho WC, Das K, Shatkin AJ, Arnold E. Detecting allosteric sites of HIV-1 reverse transcriptase by X-ray crystallographic fragment screening. J Med Chem 2013; 56:2738-46. [PMID: 23342998 DOI: 10.1021/jm301271j] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
HIV-1 reverse transcriptase (RT) undergoes a series of conformational changes during viral replication and is a central target for antiretroviral therapy. The intrinsic flexibility of RT can provide novel allosteric sites for inhibition. Crystals of RT that diffract X-rays to better than 2 Å resolution facilitated the probing of RT for new druggable sites using fragment screening by X-ray crystallography. A total of 775 fragments were grouped into 143 cocktails, which were soaked into crystals of RT in complex with the non-nucleoside drug rilpivirine (TMC278). Seven new sites were discovered, including the Incoming Nucleotide Binding, Knuckles, NNRTI Adjacent, and 399 sites, located in the polymerase region of RT, and the 428, RNase H Primer Grip Adjacent, and 507 sites, located in the RNase H region. Three of these sites (Knuckles, NNRTI Adjacent, and Incoming Nucleotide Binding) are inhibitory and provide opportunities for discovery of new anti-AIDS drugs.
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Affiliation(s)
- Joseph D Bauman
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, United States
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15
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Johnson BC, Pauly GT, Rai G, Patel D, Bauman JD, Baker HL, Das K, Schneider JP, Maloney DJ, Arnold E, Thomas CJ, Hughes SH. A comparison of the ability of rilpivirine (TMC278) and selected analogues to inhibit clinically relevant HIV-1 reverse transcriptase mutants. Retrovirology 2012; 9:99. [PMID: 23217210 PMCID: PMC3549755 DOI: 10.1186/1742-4690-9-99] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [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] [Received: 09/06/2012] [Accepted: 11/12/2012] [Indexed: 11/16/2022] Open
Abstract
Background The recently approved anti-AIDS drug rilpivirine (TMC278, Edurant) is a nonnucleoside inhibitor (NNRTI) that binds to reverse transcriptase (RT) and allosterically blocks the chemical step of DNA synthesis. In contrast to earlier NNRTIs, rilpivirine retains potency against well-characterized, clinically relevant RT mutants. Many structural analogues of rilpivirine are described in the patent literature, but detailed analyses of their antiviral activities have not been published. This work addresses the ability of several of these analogues to inhibit the replication of wild-type (WT) and drug-resistant HIV-1. Results We used a combination of structure activity relationships and X-ray crystallography to examine NNRTIs that are structurally related to rilpivirine to determine their ability to inhibit WT RT and several clinically relevant RT mutants. Several analogues showed broad activity with only modest losses of potency when challenged with drug-resistant viruses. Structural analyses (crystallography or modeling) of several analogues whose potencies were reduced by RT mutations provide insight into why these compounds were less effective. Conclusions Subtle variations between compounds can lead to profound differences in their activities and resistance profiles. Compounds with larger substitutions replacing the pyrimidine and benzonitrile groups of rilpivirine, which reorient pocket residues, tend to lose more activity against the mutants we tested. These results provide a deeper understanding of how rilpivirine and related compounds interact with the NNRTI binding pocket and should facilitate development of novel inhibitors.
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Affiliation(s)
- Barry C Johnson
- HIV Drug Resistance Program, National Cancer Institute, Frederick National Laboratory for Cancer Research, Frederick, MD 21702-1201, USA
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16
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Das K, Martinez SE, Bauman JD, Arnold E. HIV-1 reverse transcriptase complex with DNA and nevirapine reveals non-nucleoside inhibition mechanism. Nat Struct Mol Biol 2012; 19:253-9. [PMID: 22266819 PMCID: PMC3359132 DOI: 10.1038/nsmb.2223] [Citation(s) in RCA: 161] [Impact Index Per Article: 13.4] [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] [Received: 09/16/2011] [Accepted: 12/05/2011] [Indexed: 12/13/2022]
Abstract
Combinations of nucleoside and nonnucleoside inhibitors (NNRTIs) of HIV-1 reverse transcriptase (RT) are widely used in anti-AIDS therapies. Five NNRTIs including nevirapine are clinical drugs; however, the molecular mechanism of inhibition by NNRTIs is not clear. We determined the crystal structures of RT–DNA–nevirapine, RT–DNA, and RT–DNA–AZT-triphosphate complexes at 2.85, 2.70, and 2.80 Å, respectively. The RT–DNA complex in the crystal could bind nevirapine or AZT-triphosphate; however, not both. Binding of nevirapine led to opening of the NNRTI-binding pocket. The pocket formation caused shifting of the 3’-end of DNA primer by ~5.5 Å away from its polymerase active site position. Nucleic acid interactions with fingers and palm subdomains were reduced, the dNTP-binding pocket was distorted, and the thumb opened up. The structures elucidate complementary roles of nucleoside and nonnucleoside inhibitors in inhibiting RT.
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Affiliation(s)
- Kalyan Das
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, USA
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17
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Felts AK, Labarge K, Bauman JD, Patel DV, Himmel DM, Arnold E, Parniak MA, Levy RM. Identification of alternative binding sites for inhibitors of HIV-1 ribonuclease H through comparative analysis of virtual enrichment studies. J Chem Inf Model 2011; 51:1986-98. [PMID: 21714567 DOI: 10.1021/ci200194w] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The ribonuclease H (RNase H) domain on the p66 monomer of HIV-1 reverse transcriptase enzyme has become a target for inhibition. The active site is one potential binding site, but other RNase H sites can accommodate inhibitors. Using a combination of experimental and computational studies, potential new binding sites and binding modes have been identified. Libraries of compounds were screened with an experimental assay to identify actives without knowledge of the binding site. The compounds were computationally docked at putative binding sites. Based on positive enrichment of natural-product actives relative to the database of compounds, we propose that many inhibitors bind to an alternative, potentially allosteric, site centered on Q507 of p66. For a series of hydrazone compounds, a small amount of positive enrichment was obtained when active compounds were bound by induced-fit docking at the interface between the DNA:RNA substrate and the RNase H domain near residue Q500.
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Affiliation(s)
- Anthony K Felts
- BioMaPS Institute for Quantitative Biology, Rutgers University, Piscataway, New Jersey 08854, USA.
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18
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Chung S, Himmel DM, Jiang JK, Wojtak K, Bauman JD, Rausch JW, Wilson JA, Beutler JA, Thomas CJ, Arnold E, Le Grice SF. Synthesis, activity, and structural analysis of novel α-hydroxytropolone inhibitors of human immunodeficiency virus reverse transcriptase-associated ribonuclease H. J Med Chem 2011; 54:4462-73. [PMID: 21568335 PMCID: PMC3133734 DOI: 10.1021/jm2000757] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The α-hydroxytroplone, manicol (5,7-dihydroxy-2-isopropenyl-9-methyl-1,2,3,4-tetrahydro-benzocyclohepten-6-one), potently and specifically inhibits ribonuclease H (RNase H) activity of human immunodeficiency virus reverse transcriptase (HIV RT) in vitro. However, manicol was ineffective in reducing virus replication in culture. Ongoing efforts to improve the potency and specificity over the lead compound led us to synthesize 14 manicol derivatives that retain the divalent metal-chelating α-hydroxytropolone pharmacophore. These efforts were augmented by a high resolution structure of p66/p51 HIV-1 RT containing the nonnucleoside reverse transcriptase inhibitor (NNRTI), TMC278 and manicol in the DNA polymerase and RNase H active sites, respectively. We demonstrate here that several modified α-hydroxytropolones exhibit antiviral activity at noncytotoxic concentrations. Inclusion of RNase H active site mutants indicated that manicol analogues can occupy an additional site in or around the DNA polymerase catalytic center. Collectively, our studies will promote future structure-based design of improved α-hydroxytropolones to complement the NRTI and NNRTI currently in clinical use.
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Affiliation(s)
- Suhman Chung
- RT Biochemistry Section, HIV Drug Resistance Program, National Cancer Institute-Frederick, Frederick, MD 21702, USA
| | - Daniel M. Himmel
- Center for Advanced Biotechnology and Medicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA
| | | | - Krzysztof Wojtak
- Center for Advanced Biotechnology and Medicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Joseph D. Bauman
- Center for Advanced Biotechnology and Medicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Jason W. Rausch
- RT Biochemistry Section, HIV Drug Resistance Program, National Cancer Institute-Frederick, Frederick, MD 21702, USA
| | - Jennifer A. Wilson
- Molecular Discovery Program, National Cancer Institute-Frederick, Frederick, MD 21702, USA
| | - John A. Beutler
- Molecular Discovery Program, National Cancer Institute-Frederick, Frederick, MD 21702, USA
| | | | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Stuart F.J. Le Grice
- RT Biochemistry Section, HIV Drug Resistance Program, National Cancer Institute-Frederick, Frederick, MD 21702, USA,To whom correspondence should be addressed. Tel. 301-846-5256, Fax. 301-846-6013,
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19
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Das K, Bauman JD, Rim AS, Dharia C, Clark AD, Camarasa MJ, Balzarini J, Arnold E. Crystal structure of tert-butyldimethylsilyl-spiroaminooxathioledioxide-thymine (TSAO-T) in complex with HIV-1 reverse transcriptase (RT) redefines the elastic limits of the non-nucleoside inhibitor-binding pocket. J Med Chem 2011; 54:2727-37. [PMID: 21446702 DOI: 10.1021/jm101536x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
tert-Butyldimethylsilyl-spiroaminooxathioledioxide (TSAO) compounds have an embedded thymidine-analogue backbone; however, TSAO compounds invoke non-nucleoside RT inhibitor (NNRTI) resistance mutations. Our crystal structure of RT:7 (TSAO-T) complex shows that 7 binds inside the NNRTI-binding pocket, assuming a "dragon" shape, and interacts extensively with almost all the pocket residues. The structure also explains the structure-activity relationships and resistance data for TSAO compounds. The binding of 7 causes hyper-expansion of the pocket and significant rearrangement of RT subdomains. This nonoptimal complex formation is apparently responsible (1) for the lower stability of a RT (p66/p51) dimer and (2) for the lower potency of 7 despite of its extensive interactions with RT. However, the HIV-1 RT:7 structure reveals novel design features such as (1) interactions with the conserved Tyr183 from the YMDD-motif and (2) a possible way for an NNRTI to reach the polymerase active site that may be exploited in designing new NNRTIs.
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Affiliation(s)
- Kalyan Das
- Center for Advanced Biotechnology and Medicine (CABM), Rutgers University, Piscataway, New Jersey 08854, United States.
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20
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Abstract
Fragment screening has proven to be a powerful alternative to traditional methods for drug discovery. Biophysical methods, such as X-ray crystallography, NMR spectroscopy, and surface plasmon resonance, are used to screen a diverse library of small molecule compounds. Although compounds identified via this approach have relatively weak affinity, they provide a good platform for lead development and are highly efficient binders with respect to their size. Fragment screening has been utilized for a wide range of targets, including HIV-1 proteins. Here, we review the fragment screening studies targeting HIV-1 proteins using X-ray crystallography or surface plasmon resonance. These studies have successfully detected binding of novel fragments to either previously established or new sites on HIV-1 protease and reverse transcriptase. In addition, fragment screening against HIV-1 reverse transcriptase has been used as a tool to better understand the complex nature of ligand binding to a flexible target.
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Affiliation(s)
- Joseph D Bauman
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, USA
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21
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Himmel DM, Maegley KA, Pauly TA, Bauman JD, Das K, Dharia C, Clark AD, Ryan K, Hickey MJ, Love RA, Hughes SH, Bergqvist S, Arnold E. Structure of HIV-1 reverse transcriptase with the inhibitor beta-Thujaplicinol bound at the RNase H active site. Structure 2009; 17:1625-1635. [PMID: 20004166 PMCID: PMC3365588 DOI: 10.1016/j.str.2009.09.016] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Revised: 09/03/2009] [Accepted: 09/19/2009] [Indexed: 01/07/2023]
Abstract
Novel inhibitors are needed to counteract the rapid emergence of drug-resistant HIV variants. HIV-1 reverse transcriptase (RT) has both DNA polymerase and RNase H (RNH) enzymatic activities, but approved drugs that inhibit RT target the polymerase. Inhibitors that act against new targets, such as RNH, should be effective against all of the current drug-resistant variants. Here, we present 2.80 A and 2.04 A resolution crystal structures of an RNH inhibitor, beta-thujaplicinol, bound at the RNH active site of both HIV-1 RT and an isolated RNH domain. beta-thujaplicinol chelates two divalent metal ions at the RNH active site. We provide biochemical evidence that beta-thujaplicinol is a slow-binding RNH inhibitor with noncompetitive kinetics and suggest that it forms a tropylium ion that interacts favorably with RT and the RNA:DNA substrate.
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Affiliation(s)
- Daniel M. Himmel
- Center for Advanced Biotechnology and Medicine (CABM) and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854-8021, USA
| | - Karen A. Maegley
- Pfizer Global Research and Development, La Jolla Laboratories, San Diego, CA 92121, USA
| | - Tom A. Pauly
- Pfizer Global Research and Development, La Jolla Laboratories, San Diego, CA 92121, USA
| | - Joseph D. Bauman
- Center for Advanced Biotechnology and Medicine (CABM) and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854-8021, USA
| | - Kalyan Das
- Center for Advanced Biotechnology and Medicine (CABM) and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854-8021, USA
| | - Chhaya Dharia
- Center for Advanced Biotechnology and Medicine (CABM) and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854-8021, USA
| | - Arthur D. Clark
- Center for Advanced Biotechnology and Medicine (CABM) and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854-8021, USA
| | - Kevin Ryan
- Pfizer Global Research and Development, La Jolla Laboratories, San Diego, CA 92121, USA
| | - Michael J. Hickey
- Pfizer Global Research and Development, La Jolla Laboratories, San Diego, CA 92121, USA
| | - Robert A. Love
- Pfizer Global Research and Development, La Jolla Laboratories, San Diego, CA 92121, USA
| | - Stephen H. Hughes
- HIV Drug Resistance Program, NCI-Frederick, Building 539, Frederick, MD 21702-1201, USA
| | - Simon Bergqvist
- Pfizer Global Research and Development, La Jolla Laboratories, San Diego, CA 92121, USA
| | - Eddy Arnold
- Center for Advanced Biotechnology and Medicine (CABM) and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854-8021, USA,Corresponding author: , Tel.: 732-235-5323, FAX.: 732-235-5788
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22
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Cullen MD, Ho WC, Bauman JD, Das K, Arnold E, Hartman TL, Watson KM, Buckheit RW, Pannecouque C, De Clercq E, Cushman M. Crystallographic study of a novel subnanomolar inhibitor provides insight on the binding interactions of alkenyldiarylmethanes with human immunodeficiency virus-1 reverse transcriptase. J Med Chem 2009; 52:6467-73. [PMID: 19775161 DOI: 10.1021/jm901167t] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two crystal structures have been solved for separate complexes of alkenyldiarylmethane (ADAM) nonnucleoside reverse transcriptase inhibitors (NNRTI) 3 and 4 with HIV-1 reverse transcriptase (RT). The structures reveal inhibitor binding is exclusively hydrophobic in nature and the shape of the inhibitor-bound NNRTI binding pocket is unique among other reported inhibitor-RT crystal structures. Primarily, ADAMs 3 and 4 protrude from a large gap in the back side of the binding pocket, placing portions of the inhibitors unusually close to the polymerase active site and allowing 3 to form a weak hydrogen bond with Lys223. The lack of additional stabilizing interactions, beyond the observed hydrophobic surface contacts, between 4 and RT is quite perplexing given the extreme potency of the compound (IC(50) </= 1 nM). ADAM 4 was designed to be hydrolytically stable in blood plasma, and an investigation of its hydrolysis in rat plasma demonstrated it has a significantly prolonged half-life in comparison to ADAM lead compounds 1 and 2.
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Affiliation(s)
- Matthew D Cullen
- Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmaceutical Sciences, and Purdue University Center for Cancer Research, Purdue University, West Lafayette, Indiana 47907, USA
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23
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Bauman JD, Das K, Ho WC, Baweja M, Himmel DM, Clark AD, Oren DA, Boyer PL, Hughes SH, Shatkin AJ, Arnold E. Crystal engineering of HIV-1 reverse transcriptase for structure-based drug design. Nucleic Acids Res 2008; 36:5083-92. [PMID: 18676450 PMCID: PMC2528191 DOI: 10.1093/nar/gkn464] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [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: 11/14/2022] Open
Abstract
HIV-1 reverse transcriptase (RT) is a primary target for anti-AIDS drugs. Structures of HIV-1 RT, usually determined at ∼2.5–3.0 Å resolution, are important for understanding enzyme function and mechanisms of drug resistance in addition to being helpful in the design of RT inhibitors. Despite hundreds of attempts, it was not possible to obtain the structure of a complex of HIV-1 RT with TMC278, a nonnucleoside RT inhibitor (NNRTI) in advanced clinical trials. A systematic and iterative protein crystal engineering approach was developed to optimize RT for obtaining crystals in complexes with TMC278 and other NNRTIs that diffract X-rays to 1.8 Å resolution. Another form of engineered RT was optimized to produce a high-resolution apo-RT crystal form, reported here at 1.85 Å resolution, with a distinct RT conformation. Engineered RTs were mutagenized using a new, flexible and cost effective method called methylated overlap-extension ligation independent cloning. Our analysis suggests that reducing the solvent content, increasing lattice contacts, and stabilizing the internal low-energy conformations of RT are critical for the growth of crystals that diffract to high resolution. The new RTs enable rapid crystallization and yield high-resolution structures that are useful in designing/developing new anti-AIDS drugs.
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Affiliation(s)
- Joseph D Bauman
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, USA
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24
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Hudak KA, Bauman JD, Tumer NE. Pokeweed antiviral protein binds to the cap structure of eukaryotic mRNA and depurinates the mRNA downstream of the cap. RNA 2002; 8:1148-59. [PMID: 12358434 PMCID: PMC1370329 DOI: 10.1017/s1355838202026638] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Several cap-binding proteins from both the nucleus and cytosol have been identified that mediate processes such as pre-mRNA splicing, translation initiation, and mRNA turnover. Here we describe a novel cap-binding protein, pokeweed antiviral protein (PAP), a 29-kDa type I ribosome-inactivating protein (RIP) isolated from Phytolacca americana. In addition to depurinating the sarcin/ricin loop of the large rRNA, an activity common to all RIPs, we have reported recently that PAP depurinates capped, but not uncapped RNAs in vitro. Here we characterize this activity further and, using affinity chromatography, show that PAP binds to the m7Gppp cap structure. PAP UV-crosslinks to m7GpppG-capped luciferase mRNA more efficiently than GpppG-capped luciferase mRNA, indicating specificity for the methylated guanosine. We present evidence that PAP does not remove the cap structure or depurinate the m7Gppp as shown by primer extension of capped and uncapped luciferase transcripts incubated with PAP. Modeling studies of cap interaction with PAP predict that the cap structure would bind to the active site of PAP in a similar manner to guanine. We map the depurination sites on the capped luciferase RNA and illustrate that depurination occurs at specific adenine and guanine residues throughout the RNA sequence. Incubation of isolated ribosomes with PAP and increasing molar concentrations of m7GpppG relative to PAP resulted in a decrease in the level of rRNA depurination. Therefore, at elevated concentrations, the methylated cap structure competes with the adenine or guanine for binding to PAP, even though the affinity of PAP for capped message is almost fourfold lower than for rRNA. These results demonstrate that the activity of PAP is not limited to rRNA depurination, but that PAP binds to the cap structure and depurinates mRNAs downstream of the cap in vitro. These findings may have implications for understanding PAP activity in vivo.
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Affiliation(s)
- Katalin A Hudak
- Biotechnology Center for Agriculture and Environment, Department of Plant Biology and Pathology, Cook College, Rutgers University, New Brunswick, New Jersey 08903, USA
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25
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Wilson DW, Grier D, Reimer R, Bauman JD, Preston JF, Gabbay EJ. Sturcture-activity relationship of daunorubicin and its peptide derivatives. J Med Chem 1976; 19:381-4. [PMID: 1255661 DOI: 10.1021/jm00225a008] [Citation(s) in RCA: 44] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The synthesis of potentially specific antitumor peptide derivatives of daunorubicin is presented. The interaction specificites of the drugs with nucleic acids have been examined via stop-flow kinetics as well as the inhibition of DNA template activity. It is found that the biological activity of the daunorubicin derivatives against the mouse P388 tumor is directly proportional to RNA polymerase inhibition and inversely proportional to the rate of dissociation of the DNA complex. It is concluded that the biological efficacy of drugs which act at the replicative and transcriptional level may be estimated by the more rapid in vitro techniques provided that problems of permeability, solubility, stability, etc., in vivo are not encountered.
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