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Dogrammatzis C, Waisner H, Kalamvoki M. "Non-Essential" Proteins of HSV-1 with Essential Roles In Vivo: A Comprehensive Review. Viruses 2020; 13:E17. [PMID: 33374862 PMCID: PMC7824580 DOI: 10.3390/v13010017] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/19/2022] Open
Abstract
Viruses encode for structural proteins that participate in virion formation and include capsid and envelope proteins. In addition, viruses encode for an array of non-structural accessory proteins important for replication, spread, and immune evasion in the host and are often linked to virus pathogenesis. Most virus accessory proteins are non-essential for growth in cell culture because of the simplicity of the infection barriers or because they have roles only during a state of the infection that does not exist in cell cultures (i.e., tissue-specific functions), or finally because host factors in cell culture can complement their absence. For these reasons, the study of most nonessential viral factors is more complex and requires development of suitable cell culture systems and in vivo models. Approximately half of the proteins encoded by the herpes simplex virus 1 (HSV-1) genome have been classified as non-essential. These proteins have essential roles in vivo in counteracting antiviral responses, facilitating the spread of the virus from the sites of initial infection to the peripheral nervous system, where it establishes lifelong reservoirs, virus pathogenesis, and other regulatory roles during infection. Understanding the functions of the non-essential proteins of herpesviruses is important to understand mechanisms of viral pathogenesis but also to harness properties of these viruses for therapeutic purposes. Here, we have provided a comprehensive summary of the functions of HSV-1 non-essential proteins.
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Affiliation(s)
| | | | - Maria Kalamvoki
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA; (C.D.); (H.W.)
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2
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Telford E, Owsianka A, Marsden H. Stability of the Herpesvirus Ribonucleotide Reductase-Inhibiting Nonapeptide YAGAVVNDL in Extracts of HSV-1-Infected Cells. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/095632029000100307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The nonapeptide YAGAVVNDL has previously been shown to specifically inhibit ribonucleotide reductase (RR) induced by herpes simplex virus (HSV) and other herpesviruses. The stability of this peptide has been examined in extracts of HSV-infected cells. It was found to be rapidly modified to yield free tyrosine and the octapeptide AGAWNDL. Modification could be inhibited by several protease inhibitors, suggesting that it arises through cleavage of the amino-terminal tyrosine peptide bond. The implications of these results for the development of a therapeutically useful drug based on the nonapeptide are discussed.
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Affiliation(s)
- E. Telford
- Medical Research Council, Virology Unit, Church Street, Glasgow G11 5JR, UK
| | - A. Owsianka
- Medical Research Council, Virology Unit, Church Street, Glasgow G11 5JR, UK
| | - H. Marsden
- Medical Research Council, Virology Unit, Church Street, Glasgow G11 5JR, UK
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3
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Stubbe J. Ribonucleotide reductases. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 63:349-419. [PMID: 2407066 DOI: 10.1002/9780470123096.ch6] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- J Stubbe
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139
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4
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Xu H, Faber C, Uchiki T, Racca J, Dealwis C. Structures of eukaryotic ribonucleotide reductase I define gemcitabine diphosphate binding and subunit assembly. Proc Natl Acad Sci U S A 2006; 103:4028-33. [PMID: 16537480 PMCID: PMC1389703 DOI: 10.1073/pnas.0600440103] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ribonucleotide reductase (RNR) catalyzes the conversion of nucleoside diphosphates to deoxynucleoside diphosphates. Crucial for rapidly dividing cells, RNR is a target for cancer therapy. In eukaryotes, RNR comprises a heterooligomer of alpha(2) and beta(2) subunits. Rnr1, the alpha subunit, contains regulatory and catalytic sites; Rnr2, the beta subunit (in yeast, a heterodimer of Rnr2 and Rnr4), houses the diferric-tyrosyl radical crucial for catalysis. Here, we present three x-ray structures of eukaryotic Rnr1 from Saccharomyces cerevisiae: one bound to gemcitabine diphosphate (GemdP), the active metabolite of the mechanism-based chemotherapeutic agent gemcitabine; one with an Rnr2-derived peptide, and one with an Rnr4-derived peptide. Our structures reveal that GemdP binds differently from its analogue, cytidine diphosphate; because of unusual interactions of the geminal fluorines, the ribose and base of GemdP shift substantially, and loop 2, which mediates substrate specificity, adopts different conformations when binding to GemdP and cytidine diphosphate. The Rnr2 and Rnr4 peptides, which block RNR assembly, bind differently from each other but have unique modes of binding not seen in prokaryotic RNR. The Rnr2 peptide adopts a conformation similar to that previously reported from an NMR study for a mouse Rnr2-based peptide. In yeast, the Rnr2 peptide binds at subsites consisting of residues that are highly conserved among yeast, mouse, and human Rnr1s, suggesting that the mode of Rnr1-Rnr2 binding is conserved among eukaryotes. These structures provide new insights into subunit assembly and a framework for structure-based drug design targeting RNR.
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Affiliation(s)
- Hai Xu
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, M407 Walters Life Sciences, Knoxville, TN 37996-0840
| | - Catherine Faber
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, M407 Walters Life Sciences, Knoxville, TN 37996-0840
| | - Tomoaki Uchiki
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, M407 Walters Life Sciences, Knoxville, TN 37996-0840
| | - Joseph Racca
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, M407 Walters Life Sciences, Knoxville, TN 37996-0840
| | - Chris Dealwis
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, M407 Walters Life Sciences, Knoxville, TN 37996-0840
- To whom correspondence should be addressed. E-mail:
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5
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Loregian A, Palù G. Disruption of protein-protein interactions: towards new targets for chemotherapy. J Cell Physiol 2005; 204:750-62. [PMID: 15880642 DOI: 10.1002/jcp.20356] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Protein-protein interactions play a key role in various mechanisms of cellular growth and differentiation, and in the replication of pathogen organisms in host cells. Thus, inhibition of these interactions is a promising novel approach for rational drug design against a wide number of cellular and microbial targets. In the past few years, attempts to inhibit protein-protein interactions using antibodies, peptides, and synthetic or natural small molecules have met with varying degrees of success, and these will be the focus of this review.
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Affiliation(s)
- Arianna Loregian
- Department of Histology, Microbiology, and Medical Biotechnologies, University of Padova, Italy.
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6
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Abstract
Class I ribonucleotide reductases (RRs), which are well-recognized targets for cancer chemotherapeutic and antiviral agents, are composed of two different subunits, R1 and R2, and are inhibited by oligopeptides corresponding to the C-terminus of R2, which compete with R2 for binding to R1. These peptides specifically inhibit the RRs from which they are derived, and closely homologous RRs, but do not inhibit less homologous RRs. Here we review results obtained for oligopeptide inhibition of RRs from several sources, including related x-ray, NMR, and modeling results. The most extensive studies have been performed on herpes simplex virus-RR (HSV-RR) and mammalian-RR (mRR). A common model fits the data obtained for both enzymes, in which the C-terminal residue of the oligopeptide (Leu for HSV-RR, Phe for mRR) binds with high specificity to a narrow and deep hydrophobic subsite, and two or more hydrophobic groups at the N-terminal portion of the peptide bind to a broad and shallow second hydrophobic subsite. The studies have led to the development of highly potent and specific inhibitors of HSV-RR and promising inhibitors of mRR, and indicate possible directions for the development of inhibitors of bacterial and fungal RRs.
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Affiliation(s)
- Barry S Cooperman
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA.
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7
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Villarreal EC. Current and potential therapies for the treatment of herpes-virus infections. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2003; 60:263-307. [PMID: 12790345 DOI: 10.1007/978-3-0348-8012-1_8] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Human herpesviruses are found worldwide and are among the most frequent causes of viral infections in immunocompetent as well as in immunocompromised patients. During the past decade and a half a better understanding of the replication and disease-causing state of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2), varicella zoster virus (VZV), and human cytomegalovirus (HCMV) has been achieved due in part to the development of potent antiviral compounds that target these viruses. While some of these antiviral therapies are considered safe and efficacious (acyclovir, penciclovir), some have toxicities associated with them (ganciclovir and foscarnet). In addition, the increased and prolonged use of these compounds in the clinical setting, especially for the treatment of immunocompromised patients, has led to the emergence of viral resistance against most of these drugs. While resistance is not a serious issue for immunocompetent individuals, it is a real concern for immunocompromised patients, especially those with AIDS and the ones that have undergone organ transplantation. All the currently approved treatments target the viral DNA polymerase. It is clear that new drugs that are more efficacious than the present ones, are not toxic, and target a different viral function would be of great use especially for immunocompromised patients. Here, an overview is provided of the diseases caused by the herpesviruses as well as the replication strategy of the better studied members of this family for which treatments are available. We also discuss the various drugs that have been approved for the treatment of some herpesviruses in terms of structure, mechanism of action, and development of resistance. Finally, we present a discussion of viral targets other than the DNA polymerase, for which new antiviral compounds are being considered.
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Affiliation(s)
- Elcira C Villarreal
- Eli Lilly and Company, Lilly Centre for Women's Health, Indianapolis, IN 46285, USA.
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8
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Coen DM, Schaffer PA. Antiherpesvirus drugs: a promising spectrum of new drugs and drug targets. Nat Rev Drug Discov 2003; 2:278-88. [PMID: 12669027 DOI: 10.1038/nrd1065] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the absence of effective vaccines to control herpesvirus infections, nucleosidic antiviral drugs have been the mainstay of clinical treatment since their development in the late 1970s. However, given the drawbacks of these drugs, including the increasing emergence of drug-resistant clinical isolates, new strategies for treating herpesvirus infections are warranted. A range of promising new drugs with novel molecular targets has been developed, but will they cure latent infections?
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Affiliation(s)
- Donald M Coen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachussets 02115, USA.
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9
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Loregian A, Marsden HS, Palù G. Protein-protein interactions as targets for antiviral chemotherapy. Rev Med Virol 2002; 12:239-62. [PMID: 12125015 DOI: 10.1002/rmv.356] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Most cellular and viral processes depend on the coordinated formation of protein-protein interactions. With a better understanding of the molecular biology and biochemistry of human viruses it has become possible to screen for and detect inhibitors with activity against specific viral functions and to develop new approaches for the treatment of viral infections. A novel strategy to inhibit viral replication is based on the disruption of viral protein-protein complexes by peptides that mimic either face of the interaction between subunits. Peptides and peptide mimetics capable of dissociating protein-protein interactions have such exquisite specificity that they hold great promise as the next generation of therapeutic agents. This review is focused on recent developments using peptides and small molecules to inhibit protein-protein interactions between cellular and/or viral proteins with comments on the practicalities of transforming chemical leads into derivatives with the characteristics desired of medicinal compounds.
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Affiliation(s)
- Arianna Loregian
- Department of Histology, Microbiology and Medical Biotechnologies, University of Padova, 35121 Padova, Italy
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10
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Villarreal EC. Current and potential therapies for the treatment of herpesvirus infections. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2001; Spec No:185-228. [PMID: 11548208 DOI: 10.1007/978-3-0348-7784-8_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Human herpesviruses are found worldwide and are among the most frequent causes of viral infections in immunocompetent as well as in immunocompromised patients. During the past decade and a half a better understanding of the replication and disease causing state of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2), varicella-zoster virus (VZV), and human cytomegalovirus (HCMV) has been achieved due in part to the development of potent antiviral compounds that target these viruses. While some of these antiviral therapies are considered safe and efficacious (acyclovir, penciclovir), some have toxicities associated with them (ganciclovir and foscarnet). In addition, the increased and prolonged use of these compounds in the clinical setting, especially for the treatment of immunocompromised patients, has led to the emergence of viral resistance against most of these drugs. While resistance is not a serious issue for immunocompetent individuals, it is a real concern for immunocompromised patients, especially those with AIDS and the ones that have undergone organ transplantation. All the currently approved treatments target the viral DNA polymerase. It is clear that new drugs that are more efficacious than the present ones, are not toxic, and target a different viral function would be of great use especially for immunocompromised patients. Here, we provide an overview of the diseases caused by the herpesviruses as well as the replication strategy of the better studiedmembers of this family for which treatments are available. We also discuss the various drugs that have been approved for the treatment of some herpesviruses in terms of structure, mechanism of action, and development of resistance. Finally, we present a discussion of viral targets other than the DNA polymerase, for which new antiviral compounds are being considered.
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Affiliation(s)
- E C Villarreal
- Eli Lilly and Company, Infectious Diseases Research, Lilly Research Laboratories, Indianapolis, IN 46285, USA.
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11
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Villarreal EC. Current and potential therapies for the treatment of herpesvirus infections. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2001; 56:77-120. [PMID: 11417115 DOI: 10.1007/978-3-0348-8319-1_2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
Human herpesviruses are found worldwide and are among the most frequent causes of viral infections in immunocompetent as well as in immunocompromised patients. During the past decade and a half a better understanding of the replication and disease causing state of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2), varicella-zoster virus (VZV), and human cytomegalovirus (HCMV) has been achieved due in part to the development of potent antiviral compounds that target these viruses. While some of these antiviral therapies are considered safe and efficacious (acyclovir, penciclovir), some have toxicities associated with them (ganciclovir and foscarnet). In addition, the increased and prolonged use of these compounds in the clinical setting, especially for the treatment of immunocompromised patients, has led to the emergence of viral resistance against most of these drugs. While resistance is not a serious issue for immunocompetent individuals, it is a real concern for immunocompromised patients, especially those with AIDS and the ones that have undergone organ transplantation. All the currently approved treatments target the viral DNA polymerase. It is clear that new drugs that are more efficacious than the present ones, are not toxic, and target a different viral function would be of great use especially for immunocompromised patients. Here, we provide an overview of the diseases caused by the herpesviruses as well as the replication strategy of the better studied members of this family for which treatments are available. We also discuss the various drugs that have been approved for the treatment of some herpesviruses in terms of structure, mechanism of action, and development of resistance. Finally, we present a discussion of viral targets other than the DNA polymerase, for which new antiviral compounds are being considered.
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Affiliation(s)
- E C Villarreal
- Eli Lilly and Company, Infectious Diseases Research, Drop Code 0438, Lilly Research Laboratories, Indianapolis, IN 46285, USA.
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12
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Matković-Calogović D, Loregian A, D'Acunto MR, Battistutta R, Tossi A, Palù G, Zanotti G. Crystal Structure of the B Subunit of Escherichia coli Heat-labile Enterotoxin Carrying Peptides with Anti-herpes Simplex Virus Type 1 Activity. J Biol Chem 1999. [DOI: 10.1016/s0021-9258(19)87394-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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13
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Lukong KE, Elsliger MA, Mort JS, Potier M, Pshezhetsky AV. Identification of UDP-N-acetylglucosamine-phosphotransferase-binding sites on the lysosomal proteases, cathepsins A, B, and D. Biochemistry 1999; 38:73-80. [PMID: 9890884 DOI: 10.1021/bi981324r] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A key step in the targeting of soluble lysosomal enzymes is their recognition and phosphorylation by a 540 kDa multisubunit enzyme, UDP-N-acetylglucosamine-phosphotransferase (phosphotransferase). The molecular mechanism of recognition is still unknown, but previous experiments suggested that the phosphotransferase-binding sites on lysosomal proteins are represented by structurally conserved surface patches of amino acids. We identified four such regions on nonhomologous lysosomal enzymes, cathepsins A, B, and D, which were superimposed by rotating their structures around the Calpha atom of the glycosylated Asn residue. We proposed that these regions represent putative phosphotransferase-binding sites and tested synthetic peptides, derived from these regions on the basis of surface accessibility, for their ability to inhibit in vitro phosphorylation of purified cathepsins A, B, and D. Our results indicate that cathepsin A and cathepsin D have one closely related phosphotransferase recognition site represented by a structurally and topologically conserved beta-hairpin loop, similar to that previously identified in lysosomal beta-glucuronidase. The most potent inhibition of phosphorylation was demonstrated by homologous peptides derived from the regions located on cathepsin molecules opposite the oligosaccharide chains which are phosphorylated by the phosphotransferase. We propose that recognition and catalytic sites of the phosphotransferase are located on different subunits, therefore, providing an effective mechanism for binding and phosphorylation of lysosomal proteins of different molecular size.
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Affiliation(s)
- K E Lukong
- Service de Génétique Médicale, Hôpital Sainte-Justine, Université de Montréal, Québec, Canada
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14
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Duan J, Liuzzi M, Paris W, Lambert M, Lawetz C, Moss N, Jaramillo J, Gauthier J, Déziel R, Cordingley MG. Antiviral activity of a selective ribonucleotide reductase inhibitor against acyclovir-resistant herpes simplex virus type 1 in vivo. Antimicrob Agents Chemother 1998; 42:1629-35. [PMID: 9660995 PMCID: PMC105657 DOI: 10.1128/aac.42.7.1629] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The present study reports the activity of BILD 1633 SE against acyclovir (ACV)-resistant herpes simplex virus (HSV) infections in athymic nude (nu/nu) mice. BILD 1633 SE is a novel peptidomimetic inhibitor of HSV ribonucleotide reductase (RR). In vitro, it is more potent than ACV against several strains of wild-type as well as ACV-resistant HSV mutants. Its in vivo activity was tested against cutaneous viral infections in athymic nude mice infected with the ACV-resistant isolates HSV type 1 (HSV-1) dlsptk and PAAr5, which contain mutations in the viral thymidine kinase gene and the polymerase gene, respectively. Following cutaneous infection of athymic nude mice, both HSV-1 dlsptk and PAAr5 induced significant, reproducible, and persistent cutaneous lesions that lasted for more than 2 weeks. A 10-day treatment regimen with ACV given topically four times a day as a 5% cream or orally at up to 5 mg/ml in drinking water was partially effective against HSV-1 PAAr5 infection with a reduction of the area under the concentration-time curve (AUC) of 34 to 48%. The effects of ACV against HSV-1 dlsptk infection were not significant when it was administered topically and were only marginal when it was given in drinking water. Treatment under identical conditions with 5% topical BILD 1633 SE significantly reduced the cutaneous lesions caused by both HSV-1 dlsptk and PAAr5 infections. The effect of BILD 1633 SE against HSV-1 PAAr5 infections was more prominent and was inoculum and dose dependent, with AUC reductions of 96 and 67% against infections with 10(6) and 10(7) PFU per inoculation site, respectively. BILD 1633 SE also significantly decreased the lesions caused by HSV-1 dlsptk infection (28 to 51% AUC reduction). Combination therapy with topical BILD 1633 SE (5%) and ACV in drinking water (5 mg/ml) produced an antiviral effect against HSV-1 dlsptk and PAAr5 infections that was more than the sum of the effects of both drugs. This is the first report that a selective HSV RR subunit association inhibitor can be effective against ACV-resistant HSV infections in vivo.
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Affiliation(s)
- J Duan
- Bio-Méga Research Division, Boehringer Ingelheim (Canada) Ltd., Laval, Québec, Canada.
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15
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O'Brien WJ, Narasimhan J, Guy J, Tom P, Taylor JL. The effects of interferon-alpha and acyclovir on herpes simplex virus type-1 ribonucleotide reductase. Antiviral Res 1998; 38:107-16. [PMID: 9707373 DOI: 10.1016/s0166-3542(98)00016-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Herpes simplex virus-type 1 (HSV-1) encodes both the small (UL40) and large (UL39) subunits of the enzyme, ribonucleotide reductase. Treatment of HSV-1-infected cells with interferon-alpha (IFN-alpha) reduced the levels of both enzyme subunits. Reduced steady state levels of the large subunit were demonstrated by immunoblot using polyclonal antibody specific for the viral enzyme. Reduction in the amount of small subunit was shown by a reduction in the electron spin resonance signal derived from the iron-containing tyrosyl free-radical present in this subunit. Treatment of cells with 100 IU/ml of IFN-alpha decreased levels of both subunits resulting in a reduction in enzyme activity as measured by conversion of CDP to dCDP. The decrease in the amount of the large subunit was not due to a reduction in the level of its mRNA. The combination of IFN-alpha and ACV treatment of human cornea stromal cells did not result in a further reduction in amounts of ribonucleotide reductase relative to that detected with IFN-alpha alone. The IFN-alpha-induced reduction in ribonucleotide reductase activity is the likely cause of decreased levels of dGTP which we have previously demonstrated in IFN-alpha-treated, infected cells.
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Affiliation(s)
- W J O'Brien
- Department of Microbiology, Medical College of Wisconsin, Milwaukee 53266, USA
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16
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Bonneau AM, Kibler P, White P, Bousquet C, Dansereau N, Cordingley MG. Resistance of herpes simplex virus type 1 to peptidomimetic ribonucleotide reductase inhibitors: selection and characterization of mutant isolates. J Virol 1996; 70:787-93. [PMID: 8551616 PMCID: PMC189880 DOI: 10.1128/jvi.70.2.787-793.1996] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Herpes simplex virus (HSV) encodes its own ribonucleotide reductase (RR), which provides the high levels of deoxynucleoside triphosphates required for viral DNA replication in infected cells. HSV RR is composed of two distinct subunits, R1 and R2, whose association is required for enzymatic activity. Peptidomimetic inhibitors that mimic the C-terminal amino acids of R2 inhibit HSV RR by preventing the association of R1 and R2. These compounds are candidate antiviral therapeutic agents. Here we describe the in vitro selection of HSV type 1 KOS variants with three- to ninefold-decreased sensitivity to the RR inhibitor BILD 733. The resistant isolates have growth properties in vitro similar to those of wild-type KOS but are more sensitive to acyclovir, possibly as a consequence of functional impairment of their RRs. A single amino acid substitution in R1 (Ala-1091 to Ser) was associated with threefold resistance to BILD 733, whereas an additional substitution (Pro-1090 to Leu) was required for higher levels of resistance. These mutations were reintroduced into HSV type 1 KOS and shown to be sufficient to confer the resistance phenotype. Studies in vitro with RRs isolated from cells infected with these mutant viruses demonstrated that these RRs bind BILD 733 more weakly than the wild-type enzyme and are also functionally impaired, exhibiting an elevated dissociation constant (Kd) for R1-R2 subunit association and/or reduced activity (kcat). This work provides evidence that the C-terminal end of HSV R1 (residues 1090 and 1091) is involved in R2 binding interactions and demonstrates that resistance to subunit association inhibitors may be associated with compromised activity of the target enzyme.
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Affiliation(s)
- A M Bonneau
- Bio-Méga/Boehringer Ingelheim Research Inc., Laval, Québec, Canada
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17
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Liuzzi M, Déziel R, Moss N, Beaulieu P, Bonneau AM, Bousquet C, Chafouleas JG, Garneau M, Jaramillo J, Krogsrud RL. A potent peptidomimetic inhibitor of HSV ribonucleotide reductase with antiviral activity in vivo. Nature 1994; 372:695-8. [PMID: 7990963 DOI: 10.1038/372695a0] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Herpes simplex viruses (HSV) types 1 and 2 encode their own ribonucleotide reductases (RNRs) (EC 1.17.4.1) to convert ribonucleoside diphosphates into the corresponding deoxyribonucleotides. Like other iron-dependent RNRs, the viral enzyme is formed by the reversible association of two distinct homodimeric subunits. The carboxy terminus of the RNR small subunit (R2) is critical for subunit association and synthetic peptides containing these amino-acid sequences selectively inhibit the viral enzyme by preventing subunit association. Increasing evidence indicates that the HSV RNR is important for virulence and reactivation from latency. Previously, we reported on the design of HSV RNR inhibitors with enhanced inhibitory potency in vitro. We now report on BILD 1263, which to our knowledge is the first HSV RNR subunit-association inhibitor with antiviral activity in vivo. This compound suppresses the replication of HSV-1, HSV-2 and acyclovir-resistant HSV strains in cell culture, and also strongly potentiates the antiviral activity of acyclovir. Most importantly, its anti-herpetic activity is shown in a murine ocular model of HSV-1-induced keratitis, providing an example of potent nonsubstrate-based antiviral agents that prevent protein-protein interactions. The unique antiviral properties of BILD 1263 may lead to the design of new strategies to treat herpesvirus infections in humans.
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Affiliation(s)
- M Liuzzi
- Bio-Méga/Boehringer Ingelheim Research Inc., Laval, Québec, Canada
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19
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Uhlin U, Uhlin T, Eklund H. Crystallization and crystallographic investigations of ribonucleotide reductase protein R1 from Escherichia coli. FEBS Lett 1993; 336:148-52. [PMID: 8262199 DOI: 10.1016/0014-5793(93)81629-e] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Crystals of Escherichia coli ribonucleotide reductase protein R1 have been grown in complex with a synthetic peptide corresponding to the carboxyl end of protein R2. Good quality crystals could only be obtained after improvement of the purification protocol and are of the space group R32 with hexagonal cell axes a = b = 226 A and c = 341 A. They contain 3 subunits per asymmetric unit and diffract to 2.5 A resolution in synchrotron radiation. A multiple isomorphous replacement map at 5.5A, improved by solvent flattening, shows that the dimeric molecules are elongated, about 110 A long. The dimer is thin in the middle around the molecular two-fold axis. The subunit is shaped like a bowl, probably with the active site in its center.
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Affiliation(s)
- U Uhlin
- Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala Biomedical Center, Sweden
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20
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Owsianka AM, Hart G, Murphy M, Gottlieb J, Boehme R, Challberg M, Marsden HS. Inhibition of herpes simplex virus type 1 DNA polymerase activity by peptides from the UL42 accessory protein is largely nonspecific. J Virol 1993; 67:258-64. [PMID: 8380075 PMCID: PMC237359 DOI: 10.1128/jvi.67.1.258-264.1993] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
To identify regions in the UL42 protein of herpes simplex virus type 1 which affect viral DNA polymerase activity, a series of 96 overlapping pentadecapeptides spanning the entire 488 amino acids of the UL42 protein were synthesized and tested for their ability to inhibit polymerase activity on a primed single-stranded M13 DNA template. Two assays were used: formation of full-length double-stranded M13 molecules and rate of incorporation of deoxyribonucleoside triphosphates. Peptides from five noncontiguous regions of the UL42 protein were found to inhibit herpes simplex virus type 1 polymerase activity in both the presence and absence of UL42 protein. The most active peptides from each region correspond to amino acids 23 to 38 (peptide 6), 64 to 78 (peptide 14), 89 to 102 (peptide 19), 229 to 243 (peptide 47), and 279 to 293 (peptide 57). By two different methods (DNA mobility shift and DNA precipitation), peptides 14, 19, 47, and 57 were found to bind DNA; they most probably inhibit enzyme activity by this mechanism. Peptide 6 did not bind DNA and must act by some mechanism other than competing for DNA. The inhibitory peptides were also tested for activity against mammalian polymerase alpha and the Klenow fragment of Escherichia coli polymerase. Although some limited specificity was demonstrated (up to 10-fold for peptide 6), all the peptides showed significant activity against both polymerase alpha and E. coli polymerase.
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Affiliation(s)
- A M Owsianka
- Medical Research Council Virology Unit, Glasgow, United Kingdom
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21
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Simard C, Bastien N, Trudel M. Sequencing and 5'- and 3'-end transcript mapping of the gene encoding the small subunit of ribonucleotide reductase from bovine herpesvirus type-1. Virology 1992; 190:689-701. [PMID: 1325701 DOI: 10.1016/0042-6822(92)90907-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The complete nucleotide sequence of the gene encoding the small subunit of ribonucleotide reductase (RNR) from bovine herpesvirus type-1 (BHV-1) was determined. The genomic DNA fragment sequenced also represented regions corresponding to the carboxy termini of RNR large subunit and of a virion protein causing host shut-off. The small subunit polypeptide was constituted of 314 amino acid residues totalling 35.25 kDa. The major transcription initiation and termination sites of the small subunit mRNA were located 95 bases upstream and 88 nucleotides downstream from the coding region, respectively. These findings indicate that the mRNA was 1128 bases long which correlated well with the size of the polyadenylated transcript detected in Northern blot analysis (1.3 kb). Within the RNR large subunit coding region, a TATA box and two CAAT box motifs were found 26, 104, and 190 nucleotides, respectively, upstream from the transcription initiation site of the small subunit mRNA. In contrast to previous studies (Slabaugh et al., J. Virol. 1988, 62, 519-527; Boursnell et al., Virology 1991, 184, 411-416), our comparative analysis of five herpesviruses, one iridovirus, and one poxvirus small subunit protein sequences suggested that the seven viruses arose from a common lineage.
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Affiliation(s)
- C Simard
- Centre de recherche en virologie, Université du Québec, Ville de Laval, Canada
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22
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Chang L, Hannah J, Ashton W, Rasmusson G, Ikeler T, Patel G, Garsky V, Uncapher C, Yamanaka G, McClements W, Tolman R. Substituted penta- and hexapeptides as potent inhibitors of herpes simplex virus type 2 ribonucleotide reductase. Bioorg Med Chem Lett 1992. [DOI: 10.1016/s0960-894x(00)80215-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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23
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Filatov D, Ingemarson R, Gräslund A, Thelander L. The role of herpes simplex virus ribonucleotide reductase small subunit carboxyl terminus in subunit interaction and formation of iron-tyrosyl center structure. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)49608-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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24
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Wong KK, Chatterjee S. Controlling herpes simplex virus infections: is intracellular immunization the way of the future? Curr Top Microbiol Immunol 1992; 179:159-74. [PMID: 1499349 DOI: 10.1007/978-3-642-77247-4_10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- K K Wong
- Department of Hematology, City of Hope National Medical Center, Duarte, CA 91010-0269
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25
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Liuzzi M, Scouten E, Ingemarson R. Inhibition of herpes simplex virus ribonucleotide reductase by synthetic nonapeptides: a potential antiviral therapy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1992; 312:129-38. [PMID: 1325100 DOI: 10.1007/978-1-4615-3462-4_13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- M Liuzzi
- Department of Biochemistry, Bio-Mega Inc., Laval, Québec, Canada
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26
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Bushweller JH, Bartlett PA. Investigation of an octapeptide inhibitor of Escherichia coli ribonucleotide reductase by transferred nuclear Overhauser effect spectroscopy. Biochemistry 1991; 30:8144-51. [PMID: 1868090 DOI: 10.1021/bi00247a008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Several peptides contained within the C-terminal sequence of the B2 subunit of Escherichia coli ribonucleotide reductase (RNR) were investigated for their ability to inhibit the enzyme, presumably by interfering with association of the B1 and B2 subunits. AcYLVGQIDSE, corresponding by sequence homology to a nonapeptide that inhibits herpes simplex RNR [Gaudreau et al. (1987) J. Biol. Chem. 262, 12413] shows no inhibition of the E. coli enzyme (IC50 greater than 3 mM), whereas AcDDLSNFQL, the C-terminal octapeptide of the E. coli B2 subunit, is a noncompetitive inhibitor (Ki = 160 microM). Neither bradykinin (RPPGFSPFR) nor the pentapeptide AcSNFQL inhibits the E. coli enzyme. Transferred nuclear Overhauser enhancement spectroscopy was used to probe the conformation of AcDDLSNFQL when it is bound to the B1 subunit. These experiments suggest that the peptide adopts a turn in the region of Asn5 and Phe6 and that a hydrophobic cluster of the phenylalanine and leucine side chains is involved in the interaction surface.
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Affiliation(s)
- J H Bushweller
- Department of Chemistry, University of California, Berkeley 94720
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27
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Collier NC, Knox K, Schlesinger MJ. Inhibition of influenza virus formation by a peptide that corresponds to sequences in the cytoplasmic domain of the hemagglutinin. Virology 1991; 183:769-72. [PMID: 1853575 DOI: 10.1016/0042-6822(91)91008-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A decapeptide with a sequence corresponding to the cytoplasmic domain of the influenza virus hemagglutinin inhibited the release of virus particles and infectious virions when added to infected cultured cells for a 2-hr period during a one-cycle growth. Inhibition was dose-dependent in the range of 50 to 250 micrograms/ml. The peptide did not affect formation of intracellular virus-specific proteins or assembly of nucleocapsids and did not inhibit replication of two unrelated enveloped RNA viruses, Sindbis virus and vesicular stomatitis virus. Peptides of similar size but different in sequence were ineffective. We postulate that this peptide acts as a competitive inhibitor for virus-specific protein-protein interactions between the hemagglutinin and the matrix protein or nucleocapsid during virus assembly. These data offer an approach to the development of antiviral drugs based on virus specific activities.
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Affiliation(s)
- N C Collier
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110
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28
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Furlong J, Conner J, McLauchlan J, Lankinen H, Galt C, Marsden HS, Clements JB. The large subunit of herpes simplex virus type 1 ribonucleotide reductase: expression in Escherichia coli and purification. Virology 1991; 182:846-51. [PMID: 1850930 DOI: 10.1016/0042-6822(91)90627-n] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The open reading frame of the large subunit (R1) of herpes simplex virus type 1 (HSV-1) ribonucleotide reductase has been positioned downstream of the phage T7 gene 10 promoter in the expression vector, pET. Transformation of this recombinant plasmid into Escherichia coli BL21 DE3 cells containing the T7 RNA polymerase, under the control of the lac UV5 promoter, allows expression of the subunit on induction of the T7 RNA polymerase by isopropyl thiodigalactoside. The expressed protein is soluble and can be purified with yields up to 0.5 mg of R1 per litre of bacterial culture. The subunit can complement R2 produced in BHK cells or E. coli to give specific activities comparable to that produced in BHK cells infected with HSV-1. Enzyme activity reconstituted from E. coli-expressed R1 and R2 is inhibited by the nonapeptide YAGAVVNDL with an IC50 comparable to that obtained with enzyme extracted from BHK cells infected with HSV-1. Results suggest that the E. coli produced enzyme is a good source of protein for further structural and functional studies.
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Affiliation(s)
- J Furlong
- MRC Virology Unit, Glasgow, Scotland
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29
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Paradis H, Gaudreau P, Massie B, Lamarche N, Guilbault C, Gravel S, Langelier Y. Affinity purification of active subunit 1 of herpes simplex virus type 1 ribonucleotide reductase exhibiting a protein kinase activity. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)92869-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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30
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Paradis H, Langelier Y, Michaud J, Brazeau P, Gaudreau P. Studies on in vitro proteolytic sensitivity of peptides inhibiting herpes simplex virus ribonucleotide reductases lead to discovery of a stable and potent inhibitor. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1991; 37:72-9. [PMID: 1646184 DOI: 10.1111/j.1399-3011.1991.tb00735.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The nonapeptide, HSV R2-(329-337), corresponding to the subunit 2 (R2) carboxyl terminus of herpes simplex virus (HSV) ribonucleotide reductases, specifically inhibits this enzyme activity. We report here that under standard reductase assay conditions, this peptide was rapidly degraded by proteases present in the partially purified enzyme extract. The main process of proteolysis involves the successive removal of Tyr329 and Ala330, which corresponds to an aminopeptidase activity. Determination of the proteolytic susceptibility of HSV R2-(329-337) analogs showed that natural modifications which are present in the homologous varicella zoster virus (VZV) nonapeptide decreased its susceptibility to protease action 1.5-fold. Nx-acetylation, a modification known to protect peptides against aminopeptidase attacks, greatly improved the proteolytic resistance of HSV and VZV nonapeptides. Moreover, Ac-VZV R2-(298-306) exhibited a 15-fold higher potency on reductase inhibition than HSV R2-(329-337). The degradation process of HSV R2-(329-337) was partially inhibited by amastatin, bestatin, and leupeptin whereas it was completely abolished by bacitracin, suggesting a combined action of more than one aminopeptidase activity. Moreover, bacitracin protected most of these nonapeptide analogs from proteolysis, although it was less effective in preventing HSV R2-(332-337) degradation. Our results indicate that it is possible to determine, in the presence of bacitracin, the relative inhibitory potencies of HSV R2-(329-337) analogs with minimal error due to proteolytic susceptibility. Moreover, HSV R2-(329-337) modifications that were found to protect the peptide against degradation might be useful to increase its efficacy in vivo.
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Affiliation(s)
- H Paradis
- Institut du Cancer de Montréal, Cańada
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31
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Yang FD, Spanevello RA, Celiker I, Hirschmann R, Rubin H, Cooperman BS. The carboxyl terminus heptapeptide of the R2 subunit of mammalian ribonucleotide reductase inhibits enzyme activity and can be used to purify the R1 subunit. FEBS Lett 1990; 272:61-4. [PMID: 2226836 DOI: 10.1016/0014-5793(90)80449-s] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The heptapeptide, FTLDADF, identical in sequence to the last seven amino acid residues of the carboxyl terminus of the R2 subunit of mouse ribonucleotide reductase (RR), and its N alpha-acetyl derivative both inhibit calf thymus RR. The N alpha-acetyl derivative is considerably more potent, displaying a K1 of 20 microM. The same K1 was found for N-AcFTLDADF inhibition of a reconstituted ribonucleotide reductase from calf thymus R1 and mouse R2, indicating that the C-termini of calf R2 and mouse R2 might be identical. Our results, taken together with previous results of others on inhibition of viral RR, suggest that inhibition of RRs by peptides mimicking the C-terminus of R2 may be a general phenomenon. In addition, we have shown that an affinity column, FTLDADF-Sepharose 4B, can be used to prepare approximately 95% pure calf thymus R1, devoid of contamination with R2, in a very simple procedure that should be generally applicable to R1 purification from many sources.
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Affiliation(s)
- F D Yang
- Department of Chemistry, University of Pennsylvania, Philadelphia 19104
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32
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Nordlund P, Sjöberg BM, Eklund H. Three-dimensional structure of the free radical protein of ribonucleotide reductase. Nature 1990; 345:593-8. [PMID: 2190093 DOI: 10.1038/345593a0] [Citation(s) in RCA: 606] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The enzyme ribonucleotide reductase furnishes precursors for the DNA synthesis of all living cells. One of its constituents, the free radical protein, has an unusual alpha-helical structure. There are two iron centres that are about 25 A apart in the dimeric molecule. Tyrosine 122, which harbours the stable free radical necessary for the activity of ribonucleotide reductase, is buried inside the protein and is located 5 A from the closest iron atom.
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Affiliation(s)
- P Nordlund
- Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala
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33
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Darling AJ, McKay EM, Ingemarson R, Booth B. Herpes simplex virus-encoded ribonucleotide reductase: evidence for the dissociation/reassociation of the holoenzyme. Virus Genes 1990; 3:367-72. [PMID: 2161585 DOI: 10.1007/bf00569043] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
35S-labeled cells infected with herpes simplex virus type 1 (HSV-1), temperature-sensitive (ts) mutant ts 1222 were used as a source of the large subunit of the viral ribonucleotide reductase (RR) to investigate the binding of the large (RR1) and small (RR2) subunits in the active enzyme. Mixing 35S-labeled RR1 from ts 1222 with unlabeled RR1/RR2 complex from wild type (wt) infected cells resulted in the formation of a complex between 35S-labeled RR1 and unlabeled RR2, indicating that the complex between the RR1 and RR2 subunits is dynamic and subunit dissociation/reassociation occurs during enzyme function. Similar results were obtained when unlabeled HSV-2 RR was substituted for HSV-1 RR, demonstrating that the holoenzyme can be formed the large subunit of HSV-1 RR and the small subunit of HSV-2.
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Affiliation(s)
- A J Darling
- M.R.C. Virology Unit, Institute of Virology, Glasgow, Scotland
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34
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Haigh A, Greaves R, O'Hare P. Interference with the assembly of a virus-host transcription complex by peptide competition. Nature 1990; 344:257-9. [PMID: 2156166 DOI: 10.1038/344257a0] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Induction of transcription of the immediate-early (IE) genes of herpes simplex virus (HSV) involves the assembly of a DNA-binding complex containing the cellular transcription factor Oct-1 and the virus regulatory protein Vmw65 (VP16). Complex assembly can be observed using deletion variants of Vmw65 which lack the acidic C-terminal activation domain and are therefore defective for IE transactivation. Similar variants of Vmw65 interfere with IE activation by the normal protein, and with HSV replication. It has therefore been suggested that dominant interfering products of viruses such as HSV and HIV could be used in a form of intracellular immunization against virus infection. Here we report that a small peptide overlapping a region of Vmw65 which is critical for complex assembly specifically inhibits assembly of the complex but has no observed effect on the DNA-binding activity of the cellular factor alone. Selective interference with the assembly of transcription complexes by short peptides corresponding to functionally critical regions of virus regulatory proteins may be more feasible than the use of defective polypeptides as an antiviral strategy based on competitive interference.
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Affiliation(s)
- A Haigh
- Marie Curie Research Institute, Oxted, Surrey, UK
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35
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Ingemarson R, Gräslund A, Darling A, Thelander L. Herpes simplex virus ribonucleotide reductase: expression in Escherichia coli and purification to homogeneity of a tyrosyl free radical-containing, enzymatically active form of the 38-kilodalton subunit. J Virol 1989; 63:3769-76. [PMID: 2547995 PMCID: PMC250969 DOI: 10.1128/jvi.63.9.3769-3776.1989] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Infection of mammalian cells with herpes simplex virus (HSV) induces a virus-encoded ribonucleotide reductase which is different from the cellular enzyme. This essential viral enzyme consists of two nonidentical subunits of 140 and 38 kilodaltons (kDa) which have not previously been purified to homogeneity. The small subunit of ribonucleotide reductases from other species contains a tyrosyl free radical essential for activity. We have cloned the gene for the small subunit of HSV-1 ribonucleotide reductase into a tac expression plasmid vector. After transfection of Escherichia coli, expression of the 38-kDa protein was detected in immunoblots with a specific monoclonal antibody. About 30 micrograms of protein was produced per liter of bacterial culture. The 38-kDa protein was purified to homogeneity in an almost quantitative yield by immunoaffinity chromatography. It contained a tyrosyl free radical which gave a specific electron paramagnetic resonance spectrum identical to that we have observed in HSV-infected mammalian cells and clearly different from that produced by the E. coli and mammalian ribonucleotide reductases. The recombinant 38-kDa subunit had full activity when assayed in the presence of HSV-infected cell extracts deficient in the native 38-kDa subunit.
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Affiliation(s)
- R Ingemarson
- Department of Medical Biochemistry and Biophysics, University of Umeå, Sweden
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