Muscarinic toxin 7 (MT7) is one member of a family of small peptides of 65 amino acid residues derived from the venom of African mamba snakes (Dendroaspis angusticeps), which mainly target M1-subtype of muscarinic receptor . Muscarinic toxins like the nicotinic toxins have the three-finger fold structure, characteristic of the large superfamily of toxins that act at cholinergic synapses.
Muscarinic toxin 7 Crystal structure of Muscarinic toxin 7 (MT7) from PDB 2VLW
[ 1] Symbol MT7 SCOP2 1F94 / SCOPe / SUPFAM
MT7 is likely to bind to the human M1 receptor in its dimer form with the tips of MT7 loops II and III contacting one hM1 protomer and the tip of loop I binds to the other protomer.[ 2]
^ Fruchart-Gaillard C, Mourier G, Marquer C, Stura E, Birdsall NJ, Servent D (December 2008). "Different interactions between MT7 toxin and the human muscarinic M1 receptor in its free and N-methylscopolamine-occupied states". Mol. Pharmacol . 74 (6): 1554–63. doi :10.1124/mol.108.050773 . PMID 18784346 . S2CID 9480977 . ^ Fruchart-Marquer C, Fruchart-Gaillard C, Letellier G, Marcon E, Mourier G, Zinn-Justin S, Ménez A, Servent D, Gilquin B (September 2011). "Structural model of ligand-G protein-coupled receptor (GPCR) complex based on experimental double mutant cycle data: MT7 snake toxin bound to dimeric hM1 muscarinic receptor" . J Biol Chem . 286 (36): 31661–75. doi :10.1074/jbc.M111.261404 . PMC 3173127 . PMID 21685390 .
mAChRs Tooltip Muscarinic acetylcholine receptors
Agonists Antagonists 3-Quinuclidinyl benzilate 4-DAMP Aclidinium bromide (+formoterol ) Abediterol AF-DX 250 AF-DX 384 Ambutonium bromide Anisodamine Anisodine Antihistamines (first-generation) (e.g., brompheniramine , buclizine , captodiame , chlorphenamine (chlorpheniramine) , cinnarizine , clemastine , cyproheptadine , dimenhydrinate , dimetindene , diphenhydramine , doxylamine , meclizine , mequitazine , perlapine , phenindamine , pheniramine , phenyltoloxamine , promethazine , propiomazine , triprolidine ) AQ-RA 741 Atropine Atropine methonitrate Atypical antipsychotics (e.g., clozapine , fluperlapine , olanzapine (+fluoxetine ), rilapine , quetiapine , tenilapine , zotepine ) Benactyzine Benzatropine (benztropine) Benzilone Benzilylcholine mustard Benzydamine Bevonium BIBN 99 Biperiden Bornaprine Camylofin CAR-226,086 CAR-301,060 CAR-302,196 CAR-302,282 CAR-302,368 CAR-302,537 CAR-302,668 Caramiphen Cimetropium bromide Clidinium bromide Cloperastine CS-27349 Cyclobenzaprine Cyclopentolate Darifenacin DAU-5884 Desfesoterodine Dexetimide DIBD Dicycloverine (dicyclomine) Dihexyverine Difemerine Diphemanil metilsulfate Ditran Drofenine EA-3167 EA-3443 EA-3580 EA-3834 Emepronium bromide Etanautine Etybenzatropine (ethybenztropine) Fenpiverinium Fentonium bromide Fesoterodine Flavoxate Glycopyrronium bromide (+beclometasone/formoterol , +indacaterol , +neostigmine ) Hexahydrodifenidol Hexahydrosiladifenidol Hexbutinol Hexocyclium Himbacine HL-031,120 Homatropine Imidafenacin Ipratropium bromide (+salbutamol ) Isopropamide J-104,129 Hyoscyamine Mamba toxin 3 Mamba toxin 7 Mazaticol Mebeverine Meladrazine Mepenzolate Methantheline Methoctramine Methylatropine Methylhomatropine Methylscopolamine Metixene Muscarinic toxin 7 N-Ethyl-3-piperidyl benzilate N-Methyl-3-piperidyl benzilate Nefopam Octatropine methylbromide (anisotropine methylbromide) Orphenadrine Otenzepad (AF-DX 116) Otilonium bromide Oxapium iodide Oxitropium bromide Oxybutynin Oxyphencyclimine Oxyphenonium bromide PBID PD-102,807 PD-0298029 Penthienate Pethidine pFHHSiD Phenglutarimide Phenyltoloxamine Pipenzolate bromide Piperidolate Pirenzepine Piroheptine Pizotifen Poldine Pridinol Prifinium bromide Procyclidine Profenamine (ethopropazine) Propantheline bromide Propiverine Quinidine 3-Quinuclidinyl thiochromane-4-carboxylate Revefenacin Rociverine RU-47,213 SCH-57,790 SCH-72,788 SCH-217,443 Scopolamine (hyoscine) Scopolamine butylbromide (hyoscine butylbromide) Silahexacyclium Sofpironium bromide Solifenacin SSRIs Tooltip Selective serotonin reuptake inhibitors (e.g., femoxetine , paroxetine ) Telenzepine Terodiline Tetracyclic antidepressants (e.g., amoxapine , maprotiline , mianserin , mirtazapine ) Tiemonium iodide Timepidium bromide Tiotropium bromide Tiquizium bromide Tofenacin Tolterodine Tricyclic antidepressants (e.g., amitriptyline (+perphenazine ), amitriptylinoxide , butriptyline , cidoxepin , clomipramine , desipramine , desmethyldesipramine , dibenzepin , dosulepin (dothiepin) , doxepin , imipramine , lofepramine , nitroxazepine , northiaden (desmethyldosulepin) , nortriptyline , protriptyline , quinupramine , trimipramine ) Tridihexethyl Trihexyphenidyl Trimebutine Tripitamine (tripitramine) Tropacine Tropatepine Tropicamide Trospium chloride Typical antipsychotics (e.g., chlorpromazine , chlorprothixene , cyamemazine (cyamepromazine) , loxapine , mesoridazine , thioridazine ) Umeclidinium bromide (+vilanterol ) WIN-2299 Xanomeline Zamifenacin
Precursors (and prodrugs )