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von Berg L, Stern D, Weisemann J, Rummel A, Dorner MB, Dorner BG. Optimization of SNAP-25 and VAMP-2 Cleavage by Botulinum Neurotoxin Serotypes A-F Employing Taguchi Design-of-Experiments. Toxins (Basel) 2019; 11:toxins11100588. [PMID: 31614566 PMCID: PMC6832249 DOI: 10.3390/toxins11100588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/01/2019] [Accepted: 10/09/2019] [Indexed: 11/17/2022] Open
Abstract
The detection of catalytically active botulinum neurotoxins (BoNTs) can be achieved by monitoring the enzymatic cleavage of soluble NSF (N-ethylmaleimide-sensitive-factor) attachment protein receptor (SNARE) proteins by the toxins’ light chains (LC) in cleavage-based assays. Thus, for sensitive BoNT detection, optimal cleavage conditions for the clinically relevant A–F serotypes are required. Until now, a systematic evaluation of cleavage conditions for the different BoNT serotypes is still lacking. To address this issue, we optimized cleavage conditions for BoNT/A–F using the Taguchi design-of-experiments (DoE) method. To this aim, we analyzed the influence of buffer composition (pH, Zn2+, DTT (dithiothreitol), NaCl) as well as frequently used additives (BSA (bovine serum albumin), Tween 20, trimethylamine N-oxide (TMAO)) on BoNT substrate cleavage. We identified major critical factors (DTT, Zn2+, TMAO) and were able to increase the catalytic efficiency of BoNT/B, C, E, and F when compared to previously described buffers. Moreover, we designed a single consensus buffer for the optimal cleavage of all tested serotypes. Our optimized buffers are instrumental to increase the sensitivity of cleavage-based assays for BoNT detection. Furthermore, the application of the Taguchi DoE approach shows how the method helps to rationally improve enzymatic assays.
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Affiliation(s)
- Laura von Berg
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany.
| | - Daniel Stern
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany.
| | - Jasmin Weisemann
- Institut für Toxikologie, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
| | - Andreas Rummel
- Institut für Toxikologie, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
| | - Martin Bernhard Dorner
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany.
| | - Brigitte Gertrud Dorner
- Biological Toxins, Centre for Biological Threats and Special Pathogens, Robert Koch Institute, Seestr. 10, 13353 Berlin, Germany.
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2
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Behrensdorf-Nicol HA, Wild E, Bonifas U, Klimek J, Hanschmann KM, Krämer B, Kegel B. In vitro potency determination of botulinum neurotoxin serotype A based on its receptor-binding and proteolytic characteristics. Toxicol In Vitro 2018; 53:80-88. [PMID: 30016653 DOI: 10.1016/j.tiv.2018.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 06/22/2018] [Accepted: 07/13/2018] [Indexed: 11/26/2022]
Abstract
Botulinum neurotoxins (BoNTs) inhibit the release of the neurotransmitter acetylcholine from motor neurons, resulting in highly effective muscle relaxation. In clinical and aesthetic medicine, serotype BoNT/A, which is most potent for humans, is widely used to treat a continuously increasing spectrum of disorders associated with muscle overactivity. Because of the high toxicity associated with BoNTs, it is mandatory to precisely determine the potency of every batch produced for pharmaceutical purposes. Here we report a new quantitative functional in vitro assay for BoNT/A. In this binding and cleavage (BINACLE) assay, the toxin is first bound to specific receptor molecules. Then a chemical reduction is performed, thereby releasing the light chain of BoNT/A and activating its proteolytic domain. The activated light chain is finally exposed to its substrate protein SNAP-25, and the fragment resulting from the proteolytic cleavage of this protein is quantified in an antibody-mediated reaction. The BoNT/A BINACLE assay offers high specificity and sensitivity with a detection limit below 0.5 mouse lethal dose (LD50)/ml. In conclusion, this new in vitro assay for determining BoNT/A toxicity represents an alternative to the LD50 test in mice, which is the "gold standard" method for the potency testing of BoNT/A products.
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Affiliation(s)
- Heike A Behrensdorf-Nicol
- Veterinary Medicine Division, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicals), Langen, Germany.
| | - Emina Wild
- Veterinary Medicine Division, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicals), Langen, Germany
| | - Ursula Bonifas
- Veterinary Medicine Division, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicals), Langen, Germany
| | - Jolanta Klimek
- Veterinary Medicine Division, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicals), Langen, Germany
| | - Kay-Martin Hanschmann
- Microbiology Division, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicals), Langen, Germany
| | - Beate Krämer
- Veterinary Medicine Division, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicals), Langen, Germany
| | - Birgit Kegel
- Veterinary Medicine Division, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicals), Langen, Germany
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Konstantinović J, Kiris E, Kota KP, Kugelman-Tonos J, Videnović M, Cazares LH, Terzić Jovanović N, Verbić TŽ, Andjelković B, Duplantier AJ, Bavari S, Šolaja BA. New Steroidal 4-Aminoquinolines Antagonize Botulinum Neurotoxin Serotype A in Mouse Embryonic Stem Cell Derived Motor Neurons in Postintoxication Model. J Med Chem 2018; 61:1595-1608. [PMID: 29385334 DOI: 10.1021/acs.jmedchem.7b01710] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The synthesis and inhibitory potencies against botulinum neurotoxin serotype A light chain (BoNT/A LC) using in vitro HPLC based enzymatic assay for various steroidal, benzothiophene, thiophene, and adamantane 4-aminoquinoline derivatives are described. In addition, the compounds were evaluated for the activity against BoNT/A holotoxin in mouse embryonic stem cell derived motor neurons. Steroidal derivative 16 showed remarkable protection (up to 89% of uncleaved SNAP-25) even when administered 30 min postintoxication. This appears to be the first example of LC inhibitors antagonizing BoNT intoxication in mouse embryonic stem cell derived motor neurons (mES-MNs) in a postexposure model. Oral administration of 16 was well tolerated in the mouse up to 600 mg/kg, q.d. Although adequate unbound drug levels were not achieved at this dose, the favorable in vitro ADMET results strongly support further work in this series.
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Affiliation(s)
- Jelena Konstantinović
- Faculty of Chemistry, University of Belgrade , Studentski trg 16, P.O. Box 51, 11158 Belgrade, Serbia
| | - Erkan Kiris
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute , Frederick, Maryland 21702, United States
| | - Krishna P Kota
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases , 1425 Porter Street, Frederick, Maryland 21702, United States
| | - Johanny Kugelman-Tonos
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases , 1425 Porter Street, Frederick, Maryland 21702, United States
| | - Milica Videnović
- Faculty of Chemistry Innovative Centre , Studentski trg 12-16, 11158 Belgrade, Serbia
| | - Lisa H Cazares
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases , 1425 Porter Street, Frederick, Maryland 21702, United States
| | - Nataša Terzić Jovanović
- Institute of Chemistry, Technology, and Metallurgy, University of Belgrade , Njegoševa 12, 11000 Belgrade, Serbia
| | - Tatjana Ž Verbić
- Faculty of Chemistry, University of Belgrade , Studentski trg 16, P.O. Box 51, 11158 Belgrade, Serbia
| | - Boban Andjelković
- Faculty of Chemistry, University of Belgrade , Studentski trg 16, P.O. Box 51, 11158 Belgrade, Serbia
| | - Allen J Duplantier
- Molecular and Translational Sciences Division, United States Army Medical Research Institute of Infectious Diseases , 1425 Porter Street, Frederick, Maryland 21702, United States
| | - Sina Bavari
- United States Army Medical Research Institute of Infectious Diseases , 1425 Porter Street, Frederick, Maryland 21702, United States
| | - Bogdan A Šolaja
- Faculty of Chemistry, University of Belgrade , Studentski trg 16, P.O. Box 51, 11158 Belgrade, Serbia.,Serbian Academy of Sciences and Arts , Knez Mihailova 35, 11158 Belgrade, Serbia
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4
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Fonin AV, Uversky VN, Kuznetsova IM, Turoverov KK. Protein folding and stability in the presence of osmolytes. Biophysics (Nagoya-shi) 2016. [DOI: 10.1134/s0006350916020056] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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5
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Wild E, Bonifas U, Klimek J, Trösemeier JH, Krämer B, Kegel B, Behrensdorf-Nicol HA. In vitro potency determination of botulinum neurotoxin B based on its receptor-binding and proteolytic characteristics. Toxicol In Vitro 2016; 34:97-104. [PMID: 27032463 DOI: 10.1016/j.tiv.2016.03.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/21/2016] [Indexed: 01/09/2023]
Abstract
Botulinum neurotoxins (BoNTs) are the most potent toxins known. However, the paralytic effect caused by BoNT serotypes A and B is taken advantage of to treat different forms of dystonia and in cosmetic procedures. Due to the increasing areas of application, the demand for BoNTs A and B is rising steadily. Because of the high toxicity, it is mandatory to precisely determine the potency of every produced BoNT batch, which is usually accomplished by performing toxicity testing (LD50 test) in mice. Here we describe an alternative in vitro assay for the potency determination of the BoNT serotype B. In this assay, the toxin is first bound to its specific receptor molecules. After the proteolytic subunit of the toxin has been released and activated by chemical reduction, it is exposed to synaptobrevin, its substrate protein. Finally the proteolytic cleavage is quantified by an antibody-mediated detection of the neoepitope, reaching a detection limit below 0.1mouseLD50/ml. Thus, the assay, named BoNT/B binding and cleavage assay (BoNT/B BINACLE), takes into account the binding as well as the protease function of the toxin, thereby measuring its biological activity.
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Affiliation(s)
- Emina Wild
- Veterinary Medicine Division, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicals), Langen, Germany
| | - Ursula Bonifas
- Veterinary Medicine Division, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicals), Langen, Germany
| | - Jolanta Klimek
- Veterinary Medicine Division, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicals), Langen, Germany
| | - Jan-Hendrik Trösemeier
- Microbiology Division, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicals), Langen, Germany; Molecular Bioinformatics, Institute of Computer Science, Johann Wolfgang Goethe University, Frankfurt am Main, Germany
| | - Beate Krämer
- Veterinary Medicine Division, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicals), Langen, Germany
| | - Birgit Kegel
- Veterinary Medicine Division, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicals), Langen, Germany
| | - Heike A Behrensdorf-Nicol
- Veterinary Medicine Division, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicals), Langen, Germany.
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6
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Kiris E, Nuss JE, Stanford SM, Wanner LM, Cazares L, Maestre MF, Du HT, Gomba GY, Burnett JC, Gussio R, Bottini N, Panchal RG, Kane CD, Tessarollo L, Bavari S. Phosphatase Inhibitors Function as Novel, Broad Spectrum Botulinum Neurotoxin Antagonists in Mouse and Human Embryonic Stem Cell-Derived Motor Neuron-Based Assays. PLoS One 2015; 10:e0129264. [PMID: 26061731 PMCID: PMC4462581 DOI: 10.1371/journal.pone.0129264] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 05/06/2015] [Indexed: 12/05/2022] Open
Abstract
There is an urgent need to develop novel treatments to counter Botulinum neurotoxin (BoNT) poisoning. Currently, the majority of BoNT drug development efforts focus on directly inhibiting the proteolytic components of BoNT, i.e. light chains (LC). Although this is a rational approach, previous research has shown that LCs are extremely difficult drug targets and that inhibiting multi-serotype BoNTs with a single LC inhibitor may not be feasible. An alternative approach would target neuronal pathways involved in intoxication/recovery, rather than the LC itself. Phosphorylation-related mechanisms have been implicated in the intoxication pathway(s) of BoNTs. However, the effects of phosphatase inhibitors upon BoNT activity in the physiological target of BoNTs, i.e. motor neurons, have not been investigated. In this study, a small library of phosphatase inhibitors was screened for BoNT antagonism in the context of mouse embryonic stem cell-derived motor neurons (ES-MNs). Four inhibitors were found to function as BoNT/A antagonists. Subsequently, we confirmed that these inhibitors protect against BoNT/A in a dose-dependent manner in human ES-MNs. Additionally, these compounds provide protection when administered in post-intoxication scenario. Importantly, the inhibitors were also effective against BoNT serotypes B and E. To the best of our knowledge, this is the first study showing phosphatase inhibitors as broad-spectrum BoNT antagonists.
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Affiliation(s)
- Erkan Kiris
- Geneva Foundation, Tacoma, WA, United States of America
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States of America
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute (NCI), Frederick, MD, United States of America
| | - Jonathan E. Nuss
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States of America
| | - Stephanie M. Stanford
- Division of Cellular Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, United States of America
| | - Laura M. Wanner
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States of America
| | - Lisa Cazares
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States of America
| | - Michael F. Maestre
- Division of Cellular Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, United States of America
| | - Hao T. Du
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States of America
| | - Glenn Y. Gomba
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States of America
| | - James C. Burnett
- Leidos Biomedical Research, Inc., Computational Drug Development Group (CDDG), NCI, Frederick, MD, United States of America
- CDDG, Developmental Therapeutics Program, NCI, Frederick, MD, United States of America
| | - Rick Gussio
- CDDG, Developmental Therapeutics Program, NCI, Frederick, MD, United States of America
| | - Nunzio Bottini
- Division of Cellular Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, United States of America
| | - Rekha G. Panchal
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States of America
| | - Christopher D. Kane
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States of America
- Henry M. Jackson Foundation, Bethesda, MD, United States of America
- DoD Biotechnology High Performance Computing Software Applications Institute (BHSAI), Telemedicine and Advanced Technology Research Center (TATRC), US Army Medical Research and Materiel Command (USAMRMC), Frederick, MD, United States of America
| | - Lino Tessarollo
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute (NCI), Frederick, MD, United States of America
| | - Sina Bavari
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD, United States of America
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7
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Kiris E, Burnett JC, Nuss JE, Wanner LM, Peyser BD, Du HT, Gomba GY, Kota KP, Panchal RG, Gussio R, Kane CD, Tessarollo L, Bavari S. SRC family kinase inhibitors antagonize the toxicity of multiple serotypes of botulinum neurotoxin in human embryonic stem cell-derived motor neurons. Neurotox Res 2015; 27:384-98. [PMID: 25782580 PMCID: PMC4455898 DOI: 10.1007/s12640-015-9526-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 03/05/2015] [Indexed: 02/07/2023]
Abstract
Botulinum neurotoxins (BoNTs), the causative agents of botulism, are potent inhibitors of neurotransmitter release from motor neurons. There are currently no drugs to treat BoNT intoxication after the onset of the disease symptoms. In this study, we explored how modulation of key host pathways affects the process of BoNT intoxication in human motor neurons, focusing on Src family kinase (SFK) signaling. Motor neurons derived from human embryonic stem (hES) cells were treated with a panel of SFK inhibitors and intoxicated with BoNT serotypes A, B, or E (which are responsible for >95 % of human botulism cases). Subsequently, it was found that bosutinib, dasatinib, KX2-391, PP1, PP2, Src inhibitor-1, and SU6656 significantly antagonized all three of the serotypes. Furthermore, the data indicated that the treatment of hES-derived motor neurons with multiple SFK inhibitors increased the antagonistic effect synergistically. Mechanistically, the small molecules appear to inhibit BoNTs by targeting host pathways necessary for intoxication and not by directly inhibiting the toxins' proteolytic activity. Importantly, the identified inhibitors are all well-studied with some in clinical trials while others are FDA-approved drugs. Overall, this study emphasizes the importance of targeting host neuronal pathways, rather than the toxin's enzymatic components, to antagonize multiple BoNT serotypes in motor neurons.
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Affiliation(s)
- Erkan Kiris
- Geneva Foundation, Tacoma, WA, USA
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
- Neural Development Section, Mouse Cancer Genetics Program, Center for Cancer Research, NCI, Frederick, MD 21702, USA
| | - James C. Burnett
- Leidos Biomedical Research, Inc., Computational Drug Development Group (CDDG), NCI, Frederick, MD 21702, USA
- CDDG, Developmental Therapeutics Program, NCI, Frederick, MD 21702, USA
| | - Jonathan E. Nuss
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - Laura M. Wanner
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - Brian D. Peyser
- CDDG, Developmental Therapeutics Program, NCI, Frederick, MD 21702, USA
| | - Hao T. Du
- Neural Development Section, Mouse Cancer Genetics Program, Center for Cancer Research, NCI, Frederick, MD 21702, USA
| | - Glenn Y. Gomba
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - Krishna P. Kota
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - Rekha G. Panchal
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
| | - Rick Gussio
- CDDG, Developmental Therapeutics Program, NCI, Frederick, MD 21702, USA
| | - Christopher D. Kane
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
- Henry M. Jackson Foundation, Bethesda, MD, USA
- DoD Biotechnology High Performance Computing Software Applications Institute (BHSAI), Telemedicine and Advanced Technology Research Center (TATRC), US Army Medical Research and Materiel Command (USAMRMC), Frederick, MD 2170, USA
| | - Lino Tessarollo
- Neural Development Section, Mouse Cancer Genetics Program, Center for Cancer Research, NCI, Frederick, MD 21702, USA
| | - Sina Bavari
- Department of Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
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Polizzi SJ, Walsh RM, Le Magueres P, Criswell AR, Wood ZA. Human UDP-α-d-xylose Synthase Forms a Catalytically Important Tetramer That Has Not Been Observed in Crystal Structures. Biochemistry 2013; 52:3888-98. [DOI: 10.1021/bi400294e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Samuel J. Polizzi
- Department
of Biochemistry and
Molecular Biology, University of Georgia, Athens, Georgia 30602, United States
| | - Richard M. Walsh
- Department
of Biochemistry and
Molecular Biology, University of Georgia, Athens, Georgia 30602, United States
| | | | | | - Zachary A. Wood
- Department
of Biochemistry and
Molecular Biology, University of Georgia, Athens, Georgia 30602, United States
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Ouimet T, Duquesnoy S, Poras H, Fournié-Zaluski MC, Roques BP. Comparison of Fluorigenic Peptide Substrates PL50, SNAPtide, and BoTest A/E for BoNT/A Detection and Quantification. ACTA ACUST UNITED AC 2013; 18:726-35. [DOI: 10.1177/1087057113476089] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Detection and quantification of low doses of botulinum toxin serotype A (BoNT/A) in medicinal preparations require precise and sensitive methods. With mounting pressure from governmental authorities to replace the mouse LD50 assay, interest in alternative methods such as the endopeptidase assay, quantifying the toxin active moiety, is growing. Using internal collision-induced fluorescence quenching, Pharmaleads produced peptides encompassing the SNAP-25 cleavage site: a 17-mer (PL63) and a 48-mer (PL50) reaching the previously identified α-exosite, with PL50 showing higher apparent affinity for BoNT/A. Peptide mapping experiments revealed that this increased affinity is mainly due to a connecting peptide sequence between the N-terminus of PL63 and the α-exosite, identifying a new cooperative exosite on BoNT/A. Other endopeptidase substrates available, including SNAPTide and BoTest A/E, are both based on fluorescent resonance energy transfer (FRET) technology. To compare these assays, their limits of detection and quantification were determined using light chain or 150-kDa BoNT/A. Detection limits of PL50 and BoTest were over 100 times better than those using SNAPtide in standard conditions. Although the BoTest possessed a detection limit around 0.2 pM for either BoNT/A form, its quantification limit (9.7 pM) using purified BoNT/A was 12 times inferior to PL50, estimated at 0.8 pM, suitable for medicinal preparation quantification.
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10
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Opsenica I, Filipovic V, Nuss JE, Gomba LM, Opsenica D, Burnett JC, Gussio R, Solaja BA, Bavari S. The synthesis of 2,5-bis(4-amidinophenyl)thiophene derivatives providing submicromolar-range inhibition of the botulinum neurotoxin serotype A metalloprotease. Eur J Med Chem 2012; 53:374-9. [PMID: 22516424 PMCID: PMC3361628 DOI: 10.1016/j.ejmech.2012.03.043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 02/22/2012] [Accepted: 03/25/2012] [Indexed: 10/28/2022]
Abstract
Botulinum neurotoxins (BoNTs), composed of a family of seven serotypes (categorized A-G), are the deadliest of known biological toxins. The activity of the metalloprotease, light chain (LC) component of the toxins is responsible for causing the life-threatening paralysis associated with the disease botulism. Herein we report significantly more potent analogs of novel, lead BoNT serotype A LC inhibitor 2,5-bis(4-amidinophenyl)thiophene (K(i) = 10.88 μM ± 0.90 μM). Specifically, synthetic modifications involved simultaneously replacing the lead inhibitor's terminal bis-amidines with secondary amines and the systematic tethering of 4-amino-7-chloroquinoline substituents to provide derivatives with K(i) values ranging from 0.302 μM (± 0.03 μM) to 0.889μM (± 0.11 μM).
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Affiliation(s)
- Igor Opsenica
- Faculty of Chemistry, University of Belgrade, Studentski trg16, P.O. Box 51, Belgrade, Serbia
| | - Vuk Filipovic
- Faculty of Chemistry, University of Belgrade, Studentski trg16, P.O. Box 51, Belgrade, Serbia
| | - Jon E. Nuss
- United States Army Medical Research Institute of Infectious Diseases, Department of Bacteriology, 1425 Porter Street, Frederick, MD 21702, USA
| | - Laura M. Gomba
- United States Army Medical Research Institute of Infectious Diseases, Department of Bacteriology, 1425 Porter Street, Frederick, MD 21702, USA
| | - Dejan Opsenica
- Institute of Chemistry, Technology, and Metallurgy, 12 Njegoseva 12, 11001, P.O. Box 473, Belgrade, Serbia
| | - James C. Burnett
- SAIC-Frederick, Inc., National Cancer Institute at Frederick, Target Structure-Based Drug Discovery Group, P.O. Box B, Frederick, MD 21702, USA
| | - Rick Gussio
- National Cancer Institute at Frederick, Developmental Therapeutics Program, P.O. Box B, Frederick, MD 21702, USA
| | - Bogdan A. Solaja
- Faculty of Chemistry, University of Belgrade, Studentski trg16, P.O. Box 51, Belgrade, Serbia
| | - Sina Bavari
- Chief, Target Discovery and Experimental Microbiology, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, MD 21702, USA
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