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Rasetti-Escargueil C, Popoff MR. Engineering Botulinum Neurotoxins for Enhanced Therapeutic Applications and Vaccine Development. Toxins (Basel) 2020; 13:1. [PMID: 33374954 PMCID: PMC7821915 DOI: 10.3390/toxins13010001] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 02/07/2023] Open
Abstract
Botulinum neurotoxins (BoNTs) show increasing therapeutic applications ranging from treatment of locally paralyzed muscles to cosmetic benefits. At first, in the 1970s, BoNT was used for the treatment of strabismus, however, nowadays, BoNT has multiple medical applications including the treatment of muscle hyperactivity such as strabismus, dystonia, movement disorders, hemifacial spasm, essential tremor, tics, cervical dystonia, cerebral palsy, as well as secretory disorders (hyperhidrosis, sialorrhea) and pain syndromes such as chronic migraine. This review summarizes current knowledge related to engineering of botulinum toxins, with particular emphasis on their potential therapeutic applications for pain management and for retargeting to non-neuronal tissues. Advances in molecular biology have resulted in generating modified BoNTs with the potential to act in a variety of disorders, however, in addition to the modifications of well characterized toxinotypes, the diversity of the wild type BoNT toxinotypes or subtypes, provides the basis for innovative BoNT-based therapeutics and research tools. This expanding BoNT superfamily forms the foundation for new toxins candidates in a wider range of therapeutic options.
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Sikorra S, Donald S, Elliott M, Schwede S, Coker SF, Kupinski AP, Tripathi V, Foster K, Beard M, Binz T. Engineering an Effective Human SNAP-23 Cleaving Botulinum Neurotoxin A Variant. Toxins (Basel) 2020; 12:toxins12120804. [PMID: 33352834 PMCID: PMC7766560 DOI: 10.3390/toxins12120804] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/11/2020] [Accepted: 12/13/2020] [Indexed: 12/13/2022] Open
Abstract
Botulinum neurotoxin (BoNT) serotype A inhibits neurotransmitter release by cleaving SNAP-25 and represents an established pharmaceutical for treating medical conditions caused by hyperactivity of cholinergic nerves. Oversecretion from non-neuronal cells is often also the cause of diseases. Notably, excessive release of inflammatory messengers is thought to contribute to diseases such as chronic obstructive pulmonary disease, asthma, diabetes etc. The expansion of its application to these medical conditions is prevented because the major non-neuronal SNAP-25 isoform responsible for exocytosis, SNAP-23, is, in humans, virtually resistant to BoNT/A. Based on previous structural data and mutagenesis studies of SNAP-23 we optimized substrate binding pockets of the enzymatic domain for interaction with SNAP-23. Systematic mutagenesis and rational design yielded the mutations E148Y, K166F, S254A, and G305D, each of which individually increased the activity of LC/A against SNAP-23 between 3- to 23-fold. The assembled quadruple mutant showed approximately 2000-fold increased catalytic activity against human SNAP-23 in in vitro cleavage assays. A comparable increase in activity was recorded for the full-length BoNT/A quadruple mutant tested in cultivated primary neurons transduced with a fluorescently tagged-SNAP-23 encoding gene. Equipped with a suitable targeting domain this quadruple mutant promises to complete successfully tests in cells of the immune system.
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Affiliation(s)
- Stefan Sikorra
- Institut für Zellbiochemie, OE 4310, Medizinische Hochschule Hannover, 30623 Hannover, Germany; (S.S.); (S.S.)
| | - Sarah Donald
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK; (S.D.); (M.E.); (S.-F.C.); (A.P.K.); (V.T.); (K.F.)
| | - Mark Elliott
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK; (S.D.); (M.E.); (S.-F.C.); (A.P.K.); (V.T.); (K.F.)
| | - Susan Schwede
- Institut für Zellbiochemie, OE 4310, Medizinische Hochschule Hannover, 30623 Hannover, Germany; (S.S.); (S.S.)
| | - Shu-Fen Coker
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK; (S.D.); (M.E.); (S.-F.C.); (A.P.K.); (V.T.); (K.F.)
| | - Adam P. Kupinski
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK; (S.D.); (M.E.); (S.-F.C.); (A.P.K.); (V.T.); (K.F.)
| | - Vineeta Tripathi
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK; (S.D.); (M.E.); (S.-F.C.); (A.P.K.); (V.T.); (K.F.)
| | - Keith Foster
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK; (S.D.); (M.E.); (S.-F.C.); (A.P.K.); (V.T.); (K.F.)
| | - Matthew Beard
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK; (S.D.); (M.E.); (S.-F.C.); (A.P.K.); (V.T.); (K.F.)
- Correspondence: (M.B.); (T.B.); Tel.: +44(0)7850-910340 (M.B.); +49(0)511-532-2859 (T.B.)
| | - Thomas Binz
- Institut für Zellbiochemie, OE 4310, Medizinische Hochschule Hannover, 30623 Hannover, Germany; (S.S.); (S.S.)
- Correspondence: (M.B.); (T.B.); Tel.: +44(0)7850-910340 (M.B.); +49(0)511-532-2859 (T.B.)
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Davies JR, Masuyer G, Stenmark P. Structural and Biochemical Characterization of Botulinum Neurotoxin Subtype B2 Binding to Its Receptors. Toxins (Basel) 2020; 12:toxins12090603. [PMID: 32957706 PMCID: PMC7551386 DOI: 10.3390/toxins12090603] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/14/2020] [Accepted: 09/16/2020] [Indexed: 12/31/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) can be used therapeutically to treat a wide range of neuromuscular and neurological conditions. A collection of natural BoNT variants exists which can be classified into serologically distinct serotypes (BoNT/B), and further divided into subtypes (BoNT/B1, B2, …). BoNT subtypes share a high degree of sequence identity within the same serotype yet can display large variation in toxicity. One such example is BoNT/B2, which was isolated from Clostridium botulinum strain 111 in a clinical case of botulism, and presents a 10-fold lower toxicity than BoNT/B1. In an effort to understand the molecular mechanisms behind this difference in potency, we here present the crystal structures of BoNT/B2 in complex with the ganglioside receptor GD1a, and with the human synaptotagmin I protein receptor. We show, using receptor-binding assays, that BoNT/B2 has a slightly higher affinity for GD1a than BoNT/B1, and confirm its considerably weaker affinity for its protein receptors. Although the overall receptor-binding mechanism is conserved for both receptors, structural analysis suggests the lower affinity of BoNT/B2 is the result of key substitutions, where hydrophobic interactions important for synaptotagmin-binding are replaced by polar residues. This study provides a template to drive the development of future BoNT therapeutic molecules centered on assessing the natural subtype variations in receptor-binding that appears to be one of the principal stages driving toxicity.
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Affiliation(s)
- Jonathan R. Davies
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden;
| | - Geoffrey Masuyer
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden;
- Department of Pharmacy and Pharmacology, Centre for Therapeutic Innovation, University of Bath, Bath BA2 7AY, UK
- Correspondence: (G.M.); (P.S.)
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden;
- Department of Experimental Medical Science, Lund University, SE-221 00 Lund, Sweden
- Correspondence: (G.M.); (P.S.)
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Steward L, Brin MF, Brideau-Andersen A. Novel Native and Engineered Botulinum Neurotoxins. Handb Exp Pharmacol 2020; 263:63-89. [PMID: 32274579 DOI: 10.1007/164_2020_351] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Botulinum neurotoxins (BoNTs), produced by Clostridia and other bacteria, are the most potent toxins known. Their cleavage of the soluble N-ethylmaleimide-sensitive factor activating protein receptor (SNARE) proteins in neurons prevents the release of neurotransmitters, thus resulting in the muscle paralysis that is characteristic of botulism. This mechanism of action has been exploited for a variety of therapeutic and cosmetic applications of BoNTs. This chapter provides an overview of the native BoNTs, including the classical serotypes and their clinical use, mosaic BoNTs, and novel BoNTs that have been recently identified in clostridial and non-clostridial strains. In addition, the modular structure of native BoNTs, which are composed of a light chain and a heavy chain, is amenable to a multitude of novel fusions and mutations using molecular biology techniques. These novel recombinant BoNTs have been used or are being developed to further characterize the biology of toxins, to assist in vaccine production, to serve as delivery vehicles to neurons, and to be utilized as novel therapeutics for both neuronal and non-neuronal cells.
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Affiliation(s)
| | - Mitchell F Brin
- Allergan plc, Irvine, CA, USA.,University of California, Irvine, CA, USA
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Elliott M, Favre-Guilmard C, Liu SM, Maignel J, Masuyer G, Beard M, Boone C, Carré D, Kalinichev M, Lezmi S, Mir I, Nicoleau C, Palan S, Perier C, Raban E, Zhang S, Dong M, Stenmark P, Krupp J. Engineered botulinum neurotoxin B with improved binding to human receptors has enhanced efficacy in preclinical models. SCIENCE ADVANCES 2019; 5:eaau7196. [PMID: 30746458 PMCID: PMC6357751 DOI: 10.1126/sciadv.aau7196] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 12/06/2018] [Indexed: 05/10/2023]
Abstract
Although botulinum neurotoxin serotype A (BoNT/A) products are common treatments for various disorders, there is only one commercial BoNT/B product, whose low potency, likely stemming from low affinity toward its human receptor synaptotagmin 2 (hSyt2), has limited its therapeutic usefulness. We express and characterize two full-length recombinant BoNT/B1 proteins containing designed mutations E1191M/S1199Y (rBoNT/B1MY) and E1191Q/S1199W (rBoNT/B1QW) that enhance binding to hSyt2. In preclinical models including human-induced pluripotent stem cell neurons and a humanized transgenic mouse, this increased hSyt2 affinity results in high potency, comparable to that of BoNT/A. Last, we solve the cocrystal structure of rBoNT/B1MY in complex with peptides of hSyt2 and its homolog hSyt1. We demonstrate that neuronal surface receptor binding limits the clinical efficacy of unmodified BoNT/B and that modified BoNT/B proteins have promising clinical potential.
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MESH Headings
- Animals
- Botulinum Toxins, Type A/chemistry
- Botulinum Toxins, Type A/genetics
- Botulinum Toxins, Type A/metabolism
- Botulinum Toxins, Type A/pharmacology
- Crystallography, X-Ray
- Female
- Glycine/metabolism
- Humans
- Induced Pluripotent Stem Cells/drug effects
- Male
- Mice, Inbred C57BL
- Mice, Transgenic
- Muscle, Skeletal/drug effects
- Muscle, Smooth/drug effects
- Mutation
- Neurons/drug effects
- Neurons/metabolism
- Protein Engineering
- Rabbits
- Rats, Sprague-Dawley
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Recombinant Proteins/pharmacology
- Static Electricity
- Synaptotagmin II/chemistry
- Synaptotagmin II/genetics
- Synaptotagmin II/metabolism
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Affiliation(s)
- Mark Elliott
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK
| | | | - Sai Man Liu
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK
| | - Jacquie Maignel
- Ipsen Innovation, 5 Avenue du Canada, 91940 Les Ulis, France
| | - Geoffrey Masuyer
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm SE-106 91, Sweden
| | - Matthew Beard
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK
| | - Christopher Boone
- Department of Urology, Boston Children’s Hospital, Department of Microbiology and Immunobiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - Denis Carré
- Ipsen Innovation, 5 Avenue du Canada, 91940 Les Ulis, France
| | | | - Stephane Lezmi
- Ipsen Innovation, 5 Avenue du Canada, 91940 Les Ulis, France
| | - Imran Mir
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK
| | | | - Shilpa Palan
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK
| | - Cindy Perier
- Ipsen Innovation, 5 Avenue du Canada, 91940 Les Ulis, France
| | - Elsa Raban
- Ipsen Innovation, 5 Avenue du Canada, 91940 Les Ulis, France
| | - Sicai Zhang
- Department of Urology, Boston Children’s Hospital, Department of Microbiology and Immunobiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - Min Dong
- Department of Urology, Boston Children’s Hospital, Department of Microbiology and Immunobiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm SE-106 91, Sweden
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
| | - Johannes Krupp
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK
- Ipsen Innovation, 5 Avenue du Canada, 91940 Les Ulis, France
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Donald S, Elliott M, Gray B, Hornby F, Lewandowska A, Marlin S, Favre-Guilmard C, Périer C, Cornet S, Kalinichev M, Krupp J, Fonfria E. A comparison of biological activity of commercially available purified native botulinum neurotoxin serotypes A1 to F1 in vitro, ex vivo, and in vivo. Pharmacol Res Perspect 2018; 6:e00446. [PMID: 30519475 PMCID: PMC6261930 DOI: 10.1002/prp2.446] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 10/24/2018] [Accepted: 10/25/2018] [Indexed: 01/12/2023] Open
Abstract
Botulinum neurotoxin (BoNT) is a major therapeutic agent. Of seven native BoNT serotypes (A to G), only A and B are currently used in the clinic. Here we compared the potency of commercially available purified native serotypes A1 to F1 across in vitro, ex vivo, and in vivo assays. BoNT potency in vitro was assessed in rat primary cells (target protein cleavage and neurotransmitter release assays) in supraspinal, spinal, and sensory systems. BoNT potency ex vivo was measured in the mouse phrenic nerve hemidiaphragm (PNHD) assay, measuring muscle contractility. In vivo, BoNT-induced muscle relaxation in mice and rats was assessed in the Digit Abduction Score (DAS) test, while effects on body weight (BW) gain were used to assess tolerability. In all assays, all BoNT serotypes were potent toxins, except serotype D1 in vivo which failed to produce significant muscle flaccidity in mice and rats. In rats, all serotypes were well-tolerated, whereas in mice, reductions in BW were detected at high doses. Serotype A1 was the most potent serotype across in vitro, ex vivo, and in vivo assays. The rank order of potency of the serotypes revealed differences among assays. For example, species-specificity was seen for serotype B1, and to a lesser extent for serotype C1. Serotypes F1 and C1, not currently in the clinic, showed preference for sensory over motor models and therefore could be considered for development in conditions involving the somatosensory system.
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Abstract
Botulinum neurotoxins (BoNTs) and tetanus neurotoxin (TeNT) are the most potent toxins known and cause botulism and tetanus, respectively. BoNTs are also widely utilized as therapeutic toxins. They contain three functional domains responsible for receptor-binding, membrane translocation, and proteolytic cleavage of host proteins required for synaptic vesicle exocytosis. These toxins also have distinct features: BoNTs exist within a progenitor toxin complex (PTC), which protects the toxin and facilitates its absorption in the gastrointestinal tract, whereas TeNT is uniquely transported retrogradely within motor neurons. Our increasing knowledge of these toxins has allowed the development of engineered toxins for medical uses. The discovery of new BoNTs and BoNT-like proteins provides additional tools to understand the evolution of the toxins and to engineer toxin-based therapeutics. This review summarizes the progress on our understanding of BoNTs and TeNT, focusing on the PTC, receptor recognition, new BoNT-like toxins, and therapeutic toxin engineering.
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Affiliation(s)
- Min Dong
- Department of Urology, Boston Children's Hospital, Boston, Massachusetts 02115, USA; .,Department of Microbiology and Immunobiology and Department of Surgery, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Geoffrey Masuyer
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden;
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden; .,Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
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Fonfria E, Elliott M, Beard M, Chaddock JA, Krupp J. Engineering Botulinum Toxins to Improve and Expand Targeting and SNARE Cleavage Activity. Toxins (Basel) 2018; 10:toxins10070278. [PMID: 29973505 PMCID: PMC6071219 DOI: 10.3390/toxins10070278] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/29/2018] [Accepted: 07/01/2018] [Indexed: 12/14/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are highly successful protein therapeutics. Over 40 naturally occurring BoNTs have been described thus far and, of those, only 2 are commercially available for clinical use. Different members of the BoNT family present different biological properties but share a similar multi-domain structure at the molecular level. In nature, BoNTs are encoded by DNA in producing clostridial bacteria and, as such, are amenable to recombinant production through insertion of the coding DNA into other bacterial species. This, in turn, creates possibilities for protein engineering. Here, we review the production of BoNTs by the natural host and also recombinant production approaches utilised in the field. Applications of recombinant BoNT-production include the generation of BoNT-derived domain fragments, the creation of novel BoNTs with improved performance and enhanced therapeutic potential, as well as the advancement of BoNT vaccines. In this article, we discuss site directed mutagenesis, used to affect the biological properties of BoNTs, including approaches to alter their binding to neurons and to alter the specificity and kinetics of substrate cleavage. We also discuss the target secretion inhibitor (TSI) platform, in which the neuronal binding domain of BoNTs is substituted with an alternative cellular ligand to re-target the toxins to non-neuronal systems. Understanding and harnessing the potential of the biological diversity of natural BoNTs, together with the ability to engineer novel mutations and further changes to the protein structure, will provide the basis for increasing the scope of future BoNT-based therapeutics.
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Affiliation(s)
- Elena Fonfria
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK.
| | - Mark Elliott
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK.
| | - Matthew Beard
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK.
| | - John A Chaddock
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK.
| | - Johannes Krupp
- Ipsen Innovation, 5 Avenue du Canada, 91940 Les Ulis, France.
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Webb RP. Engineering of Botulinum Neurotoxins for Biomedical Applications. Toxins (Basel) 2018; 10:toxins10060231. [PMID: 29882791 PMCID: PMC6024800 DOI: 10.3390/toxins10060231] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/01/2018] [Accepted: 06/05/2018] [Indexed: 01/15/2023] Open
Abstract
Botulinum neurotoxins (BoNTs) have been used as therapeutic agents in the clinical treatment of a wide array of neuromuscular and autonomic neuronal transmission disorders. These toxins contain three functional domains that mediate highly specific neuronal cell binding, internalization and cytosolic delivery of proteolytic enzymes that cleave proteins integral to the exocytosis of neurotransmitters. The exceptional cellular specificity, potency and persistence within the neuron that make BoNTs such effective toxins, also make them attractive models for derivatives that have modified properties that could potentially expand their therapeutic repertoire. Advances in molecular biology techniques and rapid DNA synthesis have allowed a wide variety of novel BoNTs with alternative functions to be assessed as potential new classes of therapeutic drugs. This review examines how the BoNTs have been engineered in an effort to produce new classes of therapeutic molecules to address a wide array of disorders.
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Affiliation(s)
- Robert P Webb
- The Division of Molecular and Translational Sciences, United States Army Medical Research Institute for Infectious Diseases, Fort Detrick, MD 21702, USA.
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