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Harrington S, Pyche J, Burns AR, Spalholz T, Ryan KT, Baker RJ, Ching J, Rufener L, Lautens M, Kulke D, Vernudachi A, Zamanian M, Deuther-Conrad W, Brust P, Roy PJ. Nemacol is a small molecule inhibitor of C. elegans vesicular acetylcholine transporter with anthelmintic potential. Nat Commun 2023; 14:1816. [PMID: 37002199 PMCID: PMC10066365 DOI: 10.1038/s41467-023-37452-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 03/17/2023] [Indexed: 04/03/2023] Open
Abstract
Nematode parasites of humans and livestock pose a significant burden to human health, economic development, and food security. Anthelmintic drug resistance is widespread among parasites of livestock and many nematode parasites of humans lack effective treatments. Here, we present a nitrophenyl-piperazine scaffold that induces motor defects rapidly in the model nematode Caenorhabditis elegans. We call this scaffold Nemacol and show that it inhibits the vesicular acetylcholine transporter (VAChT), a target recognized by commercial animal and crop health groups as a viable anthelmintic target. We demonstrate that it is possible to create Nemacol analogs that maintain potent in vivo activity whilst lowering their affinity to the mammalian VAChT 10-fold. We also show that Nemacol enhances the ability of the anthelmintic Ivermectin to paralyze C. elegans and the ruminant nematode parasite Haemonchus contortus. Hence, Nemacol represents a promising new anthelmintic scaffold that acts through a validated anthelmintic target.
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Affiliation(s)
- Sean Harrington
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Jacob Pyche
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Andrew R Burns
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Tina Spalholz
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318, Leipzig, Germany
| | - Kaetlyn T Ryan
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Rachel J Baker
- The Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
| | - Justin Ching
- The Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
| | - Lucien Rufener
- INVENesis Sàrl, Route de Neuchâtel 15A, 2072, St Blaise (NE), Switzerland
| | - Mark Lautens
- The Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
| | - Daniel Kulke
- Research Parasiticides, Bayer Animal Health GmbH, Monheim, Germany
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50011, USA
- Global Innovation, Boehringer Ingelheim Vetmedica GmbH, Binger Str. 173, 55218, Ingelheim am Rhein, Germany
| | | | - Mostafa Zamanian
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Winnie Deuther-Conrad
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318, Leipzig, Germany
| | - Peter Brust
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318, Leipzig, Germany
- The Lübeck Institute of Experimental Dermatology, University Medical Center Schleswig-Holstein, 23562, Lübeck, Germany
| | - Peter J Roy
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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Joglekar AV, Dehari D, Anjum MM, Dulla N, Chaudhuri A, Singh S, Agrawal AK. Therapeutic potential of venom peptides: insights in the nanoparticle-mediated venom formulations. FUTURE JOURNAL OF PHARMACEUTICAL SCIENCES 2022. [DOI: 10.1186/s43094-022-00415-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Abstract
Background
Venoms are the secretions produced by animals, generally for the purpose of self-defense or catching a prey. Biochemically venoms are mainly composed of proteins, lipids, carbohydrates, ions, etc., and classified into three major classes, viz. neurotoxic, hemotoxic and cytotoxic based upon their mode of action. Venoms are composed of different specific peptides/toxins which are responsible for their unique biological actions. Though venoms are generally seen as a source of death, scientifically venom is a complex biochemical substance having a specific pharmacologic action which can be used as agents to diagnose and cure a variety of diseases in humans.
Main body
Many of these venoms have been used since centuries, and their specified therapies can also be found in ancient texts such as Charka Samhita. The modern-day example of such venom therapeutic is captopril, an antihypertensive drug developed from venom of Bothrops jararaca. Nanotechnology is a modern-day science of building materials on a nanoscale with advantages like target specificity, increased therapeutic response and diminished side effects. In the present review we have introduced the venom, sources and related constituents in brief, by highlighting the therapeutic potential of venom peptides and focusing more on the nanoformulations-based approaches. This review is an effort to compile all such report to have an idea about the future direction about the nanoplatforms which should be focused to have more clinically relevant formulations for difficult to treat diseases.
Conclusion
Venom peptides which are fatal in nature if used cautiously and effectively can save life. Several research findings suggested that many of the fatal diseases can be effectively treated with venom peptides. Nanotechnology has emerged as novel strategy in diagnosis, treatment and mitigation of diseases in more effective ways. A variety of nanoformulation approaches have been explored to enhance the therapeutic efficacy and reduce the toxicity and targeted delivery of the venom peptide conjugated with it. We concluded that venom peptides along with nanoparticles can evolve as the new era for potential treatments of ongoing and untreatable diseases.
Graphical Abstract
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Talley TT, Chao CK, Berkman CE, Richardson RJ, Thompson CM. Inhibition of Acetylcholinesterases by Stereoisomeric Organophosphorus Compounds Containing Both Thioester and p-Nitrophenyl Leaving Groups. Chem Res Toxicol 2020; 33:2455-2466. [PMID: 32833441 DOI: 10.1021/acs.chemrestox.0c00236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Studies with acetylcholinesterase (AChE) inhibited by organophosphorus (OP) compounds with two chiral centers can serve as models or surrogates for understanding the rate, orientation, and postinhibitory mechanisms by the nerve agent soman that possesses dual phosphorus and carbon chiral centers. In the current approach, stereoisomers of O-methyl, [S-(succinic acid, diethyl ester), O-(4-nitrophenyl) phosphorothiolate (MSNPs) were synthesized, and the inhibition, reactivation, and aging mechanisms were studied with electric eel AChE (eeAChE) and recombinant mouse brain AChE (rmAChE). The MSNP RPRC isomer was the strongest inhibitor of both eeAChE and rmAChE at 8- and 24-fold greater potency, respectively, than the weakest SPSC isomer. eeAChE inhibited by the RPRC- or RPSC-MSNP isomer underwent spontaneous reactivation ∼10- to 20-fold faster than the enzyme inhibited by SPRC- and SPSC-MSNP, and only 4% spontaneous reactivation was observed from the SPRC-eeAChE adduct. Using 2-pyridine aldoxime methiodide (2-PAM) or trimedoxime (TMB-4), eeAChE inhibited by RPRC- or SPRC-MSNP reactivated up to 90% and 3- to 4-fold faster than eeAChE inhibited by the RPSC- or SPSC-MSNP isomer. Spontaneous reactivation rates for rmAChE were 1.5- to 10-fold higher following inhibition by RPSC- and SPSC-MSNPs than inhibition by either RC isomer, a trend opposite to that found for eeAChE. Oxime reactivation of rmAChE following inhibition by RPRC- and SPRC-MSNPs was 2.5- to 5-fold faster than inhibition by RPSC- or SPSC-MSNPs. Due to structural similarities, MSNPs that phosphylate AChE with the loss of the p-nitrophenoxy (PNP) group form identical, nonreactivatable adducts to those formed from SP-isomalathion; however, all the MSNP isomers inhibited AChE to form adducts that reactivated. Thus, MSNPs inactivate AChE via the ejection of either PNP or thiosuccinyl groups to form a combination of reactivatable and nonreactivatable adducts, and this differs from the mechanism of AChE inhibition by isomalathion.
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Affiliation(s)
- Todd T Talley
- Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, Montana 59812, United States
| | - Chih-Kai Chao
- Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, Montana 59812, United States
| | - Clifford E Berkman
- Department of Chemistry and Biochemistry, Washington State University, Pullman, Washington 99164, United States
| | - Rudy J Richardson
- Departments of Environmental Health Sciences and Neurology, University of Michigan, Ann Arbor, Michigan 48109, United States.,Center of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Charles M Thompson
- Department of Biomedical and Pharmaceutical Sciences, The University of Montana, Missoula, Montana 59812, United States
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Ferraz CR, Arrahman A, Xie C, Casewell NR, Lewis RJ, Kool J, Cardoso FC. Multifunctional Toxins in Snake Venoms and Therapeutic Implications: From Pain to Hemorrhage and Necrosis. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00218] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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de la Rosa G, Corrales-García LL, Rodriguez-Ruiz X, López-Vera E, Corzo G. Short-chain consensus alpha-neurotoxin: a synthetic 60-mer peptide with generic traits and enhanced immunogenic properties. Amino Acids 2018; 50:885-895. [PMID: 29626299 DOI: 10.1007/s00726-018-2556-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 03/13/2018] [Indexed: 10/17/2022]
Abstract
The three-fingered toxin family and more precisely short-chain α-neurotoxins (also known as Type I α-neurotoxins) are crucial in defining the elapid envenomation process, but paradoxically, they are barely neutralized by current elapid snake antivenoms. This work has been focused on the primary structural identity among Type I neurotoxins in order to create a consensus short-chain α-neurotoxin with conserved characteristics. A multiple sequence alignment considering the twelve most toxic short-chain α-neurotoxins reported from the venoms of the elapid genera Acanthophis, Oxyuranus, Walterinnesia, Naja, Dendroaspis and Micrurus led us to propose a short-chain consensus α-neurotoxin, here named ScNtx. The synthetic ScNtx gene was de novo constructed and cloned into the expression vector pQE30 containing a 6His-Tag and an FXa proteolytic cleavage region. Escherichia coli Origami cells transfected with the pQE30/ScNtx vector expressed the recombinant consensus neurotoxin in a soluble form with a yield of 1.5 mg/L of culture medium. The 60-amino acid residue ScNtx contains canonical structural motifs similar to α-neurotoxins from African elapids and its LD50 of 3.8 µg/mice is similar to the most toxic short-chain α-neurotoxins reported from elapid venoms. Furthermore, ScNtx was also able to antagonize muscular, but not neuronal, nicotinic acetylcholine receptors (nAChR). Rabbits immunized with ScNtx were able to immune-recognize short-chain α-neurotoxins within whole elapid venoms. Type I neurotoxins are difficult to isolate and purify from natural sources; therefore, the heterologous expression of molecules such ScNtx, bearing crucial motifs and key amino acids, is a step forward to create common immunogens for developing cost-effective antivenoms with a wider spectrum of efficacy, quality and strong therapeutic value.
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Affiliation(s)
- Guillermo de la Rosa
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, UNAM, Apartado Postal 510-3, 61500, Cuernavaca, Morelos, Mexico
| | - Ligia L Corrales-García
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, UNAM, Apartado Postal 510-3, 61500, Cuernavaca, Morelos, Mexico.,Departamento de Alimentos, Facultad de Ciencias Farmacéuticas y Alimentarias, Universidad de Antioquia, AA 1226, Medellín, Colombia
| | - Ximena Rodriguez-Ruiz
- Instituto de Ciencias del Mar y Limnología/Posgrado en Ciencias del Mar y Limnologia, Universidad Nacional Autónoma de México, UNAM, Circuito exterior s/n, Ciudad Universitaria, 04510, Mexico City, Mexico
| | - Estuardo López-Vera
- Instituto de Ciencias del Mar y Limnología/Posgrado en Ciencias del Mar y Limnologia, Universidad Nacional Autónoma de México, UNAM, Circuito exterior s/n, Ciudad Universitaria, 04510, Mexico City, Mexico
| | - Gerardo Corzo
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, UNAM, Apartado Postal 510-3, 61500, Cuernavaca, Morelos, Mexico. .,Institute of Biotechnology-UNAM, Av. Universidad 2001, 62210, Cuernavaca, Morelos, Mexico.
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de la Rosa G, Pastor N, Alagón A, Corzo G. Synthetic peptide antigens derived from long-chain alpha-neurotoxins: Immunogenicity effect against elapid venoms. Peptides 2017; 88:80-86. [PMID: 28010961 DOI: 10.1016/j.peptides.2016.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 12/12/2016] [Accepted: 12/13/2016] [Indexed: 10/20/2022]
Abstract
Three-finger toxins (3FTXs), especially α-neurotoxins, are the most poorly neutralized elapid snake toxins by current antivenoms. In this work, the conserved structural similarity and motif arrangements of long-chain α-neurotoxins led us to design peptides with consensus sequences. Eight long-chain α-neurotoxins (also known as Type II) were used to generate a consensus sequence from which two peptides were chemically synthesized, LCP1 and LCP2. Rabbit sera raised against them were able to generate partially-neutralizing antibodies, which delayed mice mortality in neutralization assays against Naja haje, Dendrospis polylepis and Ophiophagus hannah venoms.
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Affiliation(s)
- Guillermo de la Rosa
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, UNAM, Apartado Postal 510-3, Cuernavaca Morelos 61500, Mexico
| | - Nina Pastor
- Centro de Investigación en Dinámica Celular, IICBA, UAEM, Av. Universidad 1001 Col. Chamilpa, Cuernavaca, Morelos 62209, Mexico
| | - Alejandro Alagón
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, UNAM, Apartado Postal 510-3, Cuernavaca Morelos 61500, Mexico
| | - Gerardo Corzo
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, UNAM, Apartado Postal 510-3, Cuernavaca Morelos 61500, Mexico.
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Orhan IE. Nature: a substantial source of auspicious substances with acetylcholinesterase inhibitory action. Curr Neuropharmacol 2013; 11:379-87. [PMID: 24381529 PMCID: PMC3744902 DOI: 10.2174/1570159x11311040003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 02/05/2013] [Accepted: 02/05/2013] [Indexed: 12/26/2022] Open
Abstract
Acetylcholinesterase (AChE) (EC 3.1.1.7) is an important enzyme that breaks down of acetylcholine in synaptic cleft in neuronal junctions. Inhibition of AChE is associated with treatment of several diseases such as Alzheimer's disease (AD), myasthenia gravis, and glaucoma as well as the mechanisms of insecticide and anthelmintic drugs. Several AChE inhibitors are available in clinical use currently for the treatment of AD; however, none of them has ability, yet, to seize progress of the disease. Consequently, an extensive research has been going on finding new AChE inhibitors. In this sense, natural inhibitors have gained great attention due to their encouraging effects toward AChE. In this review, promising candidate molecules with marked AChE inhibition from both plant and animal sources will be underlined.
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Affiliation(s)
- Ilkay Erdogan Orhan
- Department of Pharmacognosy, Faculty of Pharmacy, Gazi University, 06330 Ankara, Turkey
- Department of Pharmacognosy and Pharmaceutical Botany, Faculty of Pharmacy, Eastern Mediterranean University, Gazimagosa, The Northern Cyprus via Turkey
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Siang AS, Doley R, Vonk FJ, Kini RM. Transcriptomic analysis of the venom gland of the red-headed krait (Bungarus flaviceps) using expressed sequence tags. BMC Mol Biol 2010; 11:24. [PMID: 20350308 PMCID: PMC2861064 DOI: 10.1186/1471-2199-11-24] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 03/29/2010] [Indexed: 03/10/2023] Open
Abstract
Background The Red-headed krait (Bungarus flaviceps, Squamata: Serpentes: Elapidae) is a medically important venomous snake that inhabits South-East Asia. Although the venoms of most species of the snake genus Bungarus have been well characterized, a detailed compositional analysis of B. flaviceps is currently lacking. Results Here, we have sequenced 845 expressed sequence tags (ESTs) from the venom gland of a B. flaviceps. Of the transcripts, 74.8% were putative toxins; 20.6% were cellular; and 4.6% were unknown. The main venom protein families identified were three-finger toxins (3FTxs), Kunitz-type serine protease inhibitors (including chain B of β-bungarotoxin), phospholipase A2 (including chain A of β-bungarotoxin), natriuretic peptide (NP), CRISPs, and C-type lectin. Conclusion The 3FTxs were found to be the major component of the venom (39%). We found eight groups of unique 3FTxs and most of them were different from the well-characterized 3FTxs. We found three groups of Kunitz-type serine protease inhibitors (SPIs); one group was comparable to the classical SPIs and the other two groups to chain B of β-bungarotoxins (with or without the extra cysteine) based on sequence identity. The latter group may be functional equivalents of dendrotoxins in Bungarus venoms. The natriuretic peptide (NP) found is the first NP for any Asian elapid, and distantly related to Australian elapid NPs. Our study identifies several unique toxins in B. flaviceps venom, which may help in understanding the evolution of venom toxins and the pathophysiological symptoms induced after envenomation.
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Affiliation(s)
- Ang Swee Siang
- Department of Biological Sciences, National University of Singapore, 10 Kent Ridge Road, Singapore 117546, Singapore
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Guo L, Suarez AI, Braden MR, Gerdes JM, Thompson CM. Inhibition of acetylcholinesterase by chromophore-linked fluorophosphonates. Bioorg Med Chem Lett 2009; 20:1194-7. [PMID: 20034789 DOI: 10.1016/j.bmcl.2009.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Revised: 11/28/2009] [Accepted: 12/02/2009] [Indexed: 11/29/2022]
Abstract
Fluorophosphonate (FP) head groups were tethered to a variety of chromophores (C) via a triazole group and tested as FPC inhibitors of recombinant mouse (rMoAChE) and electric eel (EEAChE) acetylcholinesterase. The inhibitors showed bimolecular inhibition constants (k(i)) ranging from 0.3 x 10(5)M(-1)min(-1) to 10.4 x 10(5)M(-1)min(-1). When tested against rMoAChE, the dansyl FPC was 12.5-fold more potent than the corresponding inhibitor bearing a Texas Red as chromophore, whereas the Lissamine and dabsyl chromophores led to better anti-EEAChE inhibitors. Most inhibitors were equal or better inhibitors of rMoAChE than EEAChE. 3-Azidopropyl fluorophosphonate, which served as one of the FP head groups, showed excellent inhibitory potency against both AChE's ( congruent with 1 x 10(7)M(-1)min(-1)) indicating, in general, that addition of the chromophore reduced the overall anti-AChE activity. Covalent attachment of the dabsyl-FPC analog to rMoAChE was demonstrated using size exclusion chromatography and spectroscopic analysis, and visualized using molecular modeling.
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Affiliation(s)
- Lilu Guo
- Department of Chemistry, The University of Montana, Missoula, MT 59812, United States
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11
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Tamiya T, Fujimi TJ. Molecular evolution of toxin genes in Elapidae snakes. Mol Divers 2006; 10:529-43. [PMID: 17096076 DOI: 10.1007/s11030-006-9049-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2005] [Accepted: 06/21/2006] [Indexed: 11/25/2022]
Abstract
The venom of the sea krait, Laticauda semifasciata, consists primarily of two toxic proteins, phospholipase A(2) (PLA(2)) and a three-finger-structure toxin. We have cloned both toxic protein genes, including the upstream region. PLA(2) genes contain three types of inserted sequences: an AG-rich region, a chicken repeat 1-like long interspersed nucleotide element sequence and an intron II 3' side repeat sequence. The molecular divergence of L. semifasciata PLA(2) genes was defined on the basis of the inserted sequences and their sequence homology. The length of intron I in the three-finger-structure toxin genes differs from species to species. The alignment analysis of intron I of the three-finger-structure toxin genes revealed that the intron I sequence of the ancestral gene comprised ten genetic regions. A hypothetical evolutionary process for the three-finger-structure toxin genes has also been developed.
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Affiliation(s)
- Toru Tamiya
- Department of Chemistry, Faculty of Science and Technology, Sophia University, Tokyo, Japan.
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12
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Bui JM, Radic Z, Taylor P, McCammon JA. Conformational transitions in protein-protein association: binding of fasciculin-2 to acetylcholinesterase. Biophys J 2006; 90:3280-7. [PMID: 16473897 PMCID: PMC1432132 DOI: 10.1529/biophysj.105.075564] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The neurotoxin fasciculin-2 (FAS2) is a picomolar inhibitor of synaptic acetylcholinesterase (AChE). The dynamics of binding between FAS2 and AChE is influenced by conformational fluctuations both before and after protein encounter. Submicrosecond molecular dynamics trajectories of apo forms of fasciculin, corresponding to different conformational substates, are reported here with reference to the conformational changes of loop I of this three-fingered toxin. This highly flexible loop exhibits an ensemble of conformations within each substate corresponding to its functions. The high energy barrier found between the two major substates leads to transitions that are slow on the timescale of the diffusional encounter of noninteracting FAS2 and AChE. The more stable of the two apo substates may not be the one observed in the complex with AChE. It seems likely that the more stable apo form binds rapidly to AChE and conformational readjustments then occur in the resulting encounter complex.
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Affiliation(s)
- Jennifer M Bui
- Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of California, San Diego, La Jolla, California 92093-0365, USA.
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Martinez-Pena y Valenzuela I, Hume RI, Krejci E, Akaaboune M. In vivo regulation of acetylcholinesterase insertion at the neuromuscular junction. J Biol Chem 2005; 280:31801-8. [PMID: 15998641 DOI: 10.1074/jbc.m502874200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The efficiency of synaptic transmission between nerve and muscle depends on the number and density of acetylcholinesterase molecules (AChE) at the neuromuscular junction. However, little is known about the way this density is maintained and regulated in vivo. By using time lapse and quantitative fluorescence imaging assays in living mice, we demonstrated that insertion of new AChEs occurs within hours of saturating pre-existing AChEs with fasciculin2, a snake toxin that selectively labels AChE. In the absence of muscle postsynaptic activity or evoked nerve presynaptic neurotransmitter release, AChE insertion was decreased significantly, whereas direct stimulation of the muscle completely restored AChE insertion to control levels. This activity-dependent AChE insertion is mediated by intracellular calcium. In muscle stimulated in the presence of a Ca2+ channel blocker or calcium-permeable Ca2+ chelator, AChE insertion into synapses was significantly decreased, whereas ryanodine or ionophore A12387 treatment of blocked and unstimulated synapses significantly increased AChE insertion. These results demonstrated that synaptic activity is critical for AChE insertion and indicated that a rise in intracellular calcium either through voltage-gated calcium channels or from intracellular stores is critical for proper AChE insertion into the adult synapse.
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Kukkonen A, Peräkylä M, Akerman KEO, Näsman J. Muscarinic Toxin 7 Selectivity Is Dictated by Extracellular Receptor Loops. J Biol Chem 2004; 279:50923-9. [PMID: 15452105 DOI: 10.1074/jbc.m406424200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Muscarinic toxin 7 (MT7) is a mamba venom protein antagonist with extremely high selectivity for the M1 muscarinic acetylcholine receptor. To map the sites for the interaction of MT7 with muscarinic receptors we have used chimeric M1:M3 receptors and site-directed mutagenesis of the M3 and M4 receptor subtypes. Two Glu residues in M1, one in extracellular loop 2 and one in extracellular loop 3, were found to be important for the high affinity binding of MT7. Substitution of the corresponding Lys residues in the M3 receptor with Glu converted the M3 mutant to an MT7 binding receptor, albeit with lower affinity compared with M1. A Phe --> Tyr substitution in extracellular loop 2 of M3 together with the 2 Glu mutations generated a receptor with an increased MT7 affinity (apparent Ki = 0.26 nM in a functional assay) compared with the M1 receptor (apparent Ki = 1.31 nM). The importance of the identified amino acid residues was confirmed with a mutated M4 receptor constructs. The results indicate that the high selectivity of MT7 for the M1 receptor depends on very few residues, thus providing good prospects for future design and synthesis of muscarinic receptor-selective ligands.
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Affiliation(s)
- Anu Kukkonen
- A. I. Virtanen Institute for Molecular Sciences, Department of Neurobiology, Kuopio University, FIN-70211 Kuopio, Finland
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Osipov AV, Astapova MV, Tsetlin VI, Utkin YN. The first representative of glycosylated three-fingered toxins. Cytotoxin from the Naja kaouthia cobra venom. ACTA ACUST UNITED AC 2004; 271:2018-27. [PMID: 15128311 DOI: 10.1111/j.1432-1033.2004.04115.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
There are different glycosylated proteins in snake venoms, but no glycosylated representatives of a large family of three-fingered toxins have previously been detected. A new glycoprotein was isolated from the venom of the Thai cobra Naja kaouthia. MALDI MS of the glycoprotein contained an array of peaks in the range from approximately 8900 to approximately 9400 Da indicating its microheterogeneity. Carbohydrate analysis showed the presence of mannose, galactose, N-acetylglucosamine, fucose and neuraminic acid. The N-terminal sequence of the glycoprotein was identical to that of cytotoxin 3 (CX3) from N. kaouthia, and CD spectra of the glycoprotein and CX3 were almost the same. Cleavage of a glycan moiety by N-glycosidase F gave a protein of molecular mass practically coinciding with that of CX3. MALDI MS of the tryptic digest of reduced glycoprotein S-pyridylethylated at cysteine residues, contained peaks corresponding to all tryptic fragments of CX3, with the exception of fragment 24-30. The peak corresponding to this peptide appeared in the mass-spectrum of similarly treated deglycosylated glycoprotein. These data show that the potential N-glycosylation site at Asn29 in CX3 is utilized for glycan attachment and that the glycoprotein is glycosylated CX3. In vivo toxicity of the glycoprotein to the cricket Gryllus assimilis was twofold lower than that of CX3. The cytotoxic activity of the glycoprotein towards HL60 cells was about two orders of magnitude lower than that of CX3, but could be made equal to the CX3 cytotoxicity by deglycosylation. Thus for the first time we have isolated a glycosylated three-fingered snake venom toxin wherein glycosylation appears to modulate its biological activity.
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Affiliation(s)
- Alexey V Osipov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
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16
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Zeev-Ben-Mordehai T, Silman I, Sussman JL. Acetylcholinesterase in motion: visualizing conformational changes in crystal structures by a morphing procedure. Biopolymers 2003; 68:395-406. [PMID: 12601798 DOI: 10.1002/bip.10287] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In order to visualize and appreciate conformational changes between homologous three-dimensional (3D) protein structures or protein/inhibitor complexes, we have developed a user-friendly morphing procedure. It enabled us to detect coordinated conformational changes not easily discernible by analytic methods or by comparison of static images. This procedure was applied to comparison of native Torpedo californica acetylcholinesterase and of complexes with reversible inhibitors and conjugates with covalent inhibitors. It was likewise shown to be valuable for the visualization of conformational differences between acetylcholinesterases from different species. The procedure involves generation, in Cartesian space, of 25 interpolated intermediate structures between the initial and final 3D structures, which then serve as the individual frames in a QuickTime movie.
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Affiliation(s)
- T Zeev-Ben-Mordehai
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel
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17
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Tai K, Shen T, Henchman RH, Bourne Y, Marchot P, McCammon JA. Mechanism of acetylcholinesterase inhibition by fasciculin: a 5-ns molecular dynamics simulation. J Am Chem Soc 2002; 124:6153-61. [PMID: 12022850 DOI: 10.1021/ja017310h] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Our previous molecular dynamics simulation (10 ns) of mouse acetylcholinesterase (EC 3.1.1.7) revealed complex fluctuation of the enzyme active site gorge. Now we report a 5-ns simulation of acetylcholinesterase complexed with fasciculin 2. Fasciculin 2 binds to the gorge entrance of acetylcholinesterase with excellent complementarity and many polar and hydrophobic interactions. In this simulation of the protein-protein complex, where fasciculin 2 appears to sterically block access of ligands to the gorge, again we observe a two-peaked probability distribution of the gorge width. When fasciculin is present, the gorge width distribution is altered such that the gorge is more likely to be narrow. Moreover, there are large increases in the opening of alternative passages, namely, the side door (near Thr 75) and the back door (near Tyr 449). Finally, the catalytic triad arrangement in the acetylcholinesterase active site is disrupted with fasciculin bound. These data support that, in addition to the steric obstruction seen in the crystal structure, fasciculin may inhibit acetylcholinesterase by combined allosteric and dynamical means. Additional data from these simulations can be found at http://mccammon.ucsd.edu/.
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Affiliation(s)
- Kaihsu Tai
- Howard Hughes Medical Institute and Department of Chemistry, University of California, San Diego, La Jolla, California 92093-0365, USA
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18
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Sharma KV, Koenigsberger C, Brimijoin S, Bigbee JW. Direct evidence for an adhesive function in the noncholinergic role of acetylcholinesterase in neurite outgrowth. J Neurosci Res 2001; 63:165-75. [PMID: 11169626 DOI: 10.1002/1097-4547(20010115)63:2<165::aid-jnr1008>3.0.co;2-o] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Acetylcholinesterase (AChE) can promote neurite outgrowth through a mechanism that is independent of its role in hydrolyzing the neurotransmitter acetylcholine. It has been proposed that this neuritogenic capacity of AChE may result from its intrinsic capacity to function in adhesion. In this study we directly tested this hypothesis using neuroblastoma cell lines that have been engineered for altered cell-surface expression of AChE. Using a microtiter-plate adhesion assay and the electrical cell-substrate impedance-sensing (ECIS) method, we demonstrate that the level of cell-substratum adhesion of these cells directly correlates with their level of AChE expression. Furthermore, this adhesion is blocked by either an anti-AChE antibody or a highly specific AChE inhibitor (BW284c51), both of which have also been shown to block neurite outgrowth. In addition, cells that overexpress AChE showed enhanced neurite initiation. By employing cell lines with different levels of AChE expression in two types of cell-substratum adhesion assays, our current studies provide evidence for an adhesive function for AChE. These results, together with the fact that AChE shares sequence homology and structural similarities with several known cell adhesion molecules, support the hypothesis that AChE promotes neurite outgrowth, at least in part, through an adhesive function.
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Affiliation(s)
- K V Sharma
- Department of Anatomy, Virginia Commonwealth University, Richmond, VA 23298-0709, USA
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Baker N, Holst M, Wang F. Adaptive multilevel finite element solution of the Poisson-Boltzmann equation II. Refinement at solvent-accessible surfaces in biomolecular systems. J Comput Chem 2000. [DOI: 10.1002/1096-987x(20001130)21:15<1343::aid-jcc2>3.0.co;2-k] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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20
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Baker N, Holst M, Wang F. Adaptive multilevel finite element solution of the Poisson-Boltzmann equation II. Refinement at solvent-accessible surfaces in biomolecular systems. J Comput Chem 2000. [DOI: 10.1002/1096-987x(20001130)21:15%3c1343::aid-jcc2%3e3.0.co;2-k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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