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| [[Image:1b45.gif|left|200px]] | | {{Seed}} |
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| {{STRUCTURE_1b45| PDB=1b45 | SCENE= }} | | {{STRUCTURE_1b45| PDB=1b45 | SCENE= }} |
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| '''ALPHA-CNIA CONOTOXIN FROM CONUS CONSORS, NMR, 43 STRUCTURES'''
| | ===ALPHA-CNIA CONOTOXIN FROM CONUS CONSORS, NMR, 43 STRUCTURES=== |
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| ==Overview==
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| Two novel alpha-conotoxins were purified and characterized from the venom of the fish-hunting cone snail Conus consors. These peptides were identified by screening HPLC fractions of the crude venom and by binding experiments with Torpedo nicotinic acetylcholine receptor. The toxins named alpha-CnIA and alpha-CnIB exhibited sequences of 14 and 12 amino acids, respectively. The alpha-CnIA represents the main alpha-conotoxin contained in the venom, whereas alpha-CnIB is present in a relatively small amount. Chemical synthesis of alpha-CnIA was carried out using the Fmoc methodology by selective disulfide bond formation. The biological activity of the toxin was assessed in fish and mice. The alpha-CnIA inhibited the fixation of iodinated alpha-bungarotoxin to Torpedo nicotinic acetylcholine receptors with an IC50 of 0.19 microM which can be compared to the IC50 of 0.31 microM found for the previously characterized alpha-MI isolated from the piscivorous Conus magus. The synthetic alpha-CnIA blocked spontaneous and evoked synaptic potentials in frog and mouse isolated neuromuscular preparations at sub-micromolar concentrations. Solution NMR of this toxin indicated a conformational heterogeneity with the existence of different conformers in solution, at slow and intermediate exchange rates relative to the NMR chemical shift time scale, similar to that reported for alpha-GI and alpha-MI. NMR structures were calculated for the major NMR signals representing more than 80% of the population at 5 degrees C.
| | The line below this paragraph, {{ABSTRACT_PUBMED_10320362}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 10320362 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_10320362}} |
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| ==About this Structure== | | ==About this Structure== |
| 1B45 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Conus_consors Conus consors]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1B45 OCA]. | | 1B45 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Conus_consors Conus consors]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1B45 OCA]. |
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| ==Reference== | | ==Reference== |
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| [[Category: Nicotinic acetylcholine receptor]] | | [[Category: Nicotinic acetylcholine receptor]] |
| [[Category: Toxin]] | | [[Category: Toxin]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 11:02:32 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jun 30 18:12:20 2008'' |
