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1a0m
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(New page: 200px<br /><applet load="1a0m" size="450" color="white" frame="true" align="right" spinBox="true" caption="1a0m, resolution 1.1Å" /> '''1.1 ANGSTROM CRYSTAL ...) |
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| - | [[Image:1a0m.gif|left|200px]]<br /><applet load="1a0m" size=" | + | [[Image:1a0m.gif|left|200px]]<br /><applet load="1a0m" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1a0m, resolution 1.1Å" /> | caption="1a0m, resolution 1.1Å" /> | ||
'''1.1 ANGSTROM CRYSTAL STRUCTURE OF A-CONOTOXIN [TYR15]-EPI'''<br /> | '''1.1 ANGSTROM CRYSTAL STRUCTURE OF A-CONOTOXIN [TYR15]-EPI'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Conotoxins are valuable probes of receptors and ion channels because of | + | Conotoxins are valuable probes of receptors and ion channels because of their small size and highly selective activity. alpha-Conotoxin EpI, a 16-residue peptide from the mollusk-hunting Conus episcopatus, has the amino acid sequence GCCSDPRCNMNNPDY(SO3H)C-NH2 and appears to be an extremely potent and selective inhibitor of the alpha3beta2 and alpha3beta4 neuronal subtypes of the nicotinic acetylcholine receptor (nAChR). The desulfated form of EpI ([Tyr15]EpI) has a potency and selectivity for the nAChR receptor similar to those of EpI. Here we describe the crystal structure of [Tyr15]EpI solved at a resolution of 1.1 A using SnB. The asymmetric unit has a total of 284 non-hydrogen atoms, making this one of the largest structures solved de novo by direct methods. The [Tyr15]EpI structure brings to six the number of alpha-conotoxin structures that have been determined to date. Four of these, [Tyr15]EpI, PnIA, PnIB, and MII, have an alpha4/7 cysteine framework and are selective for the neuronal subtype of the nAChR. The structure of [Tyr15]EpI has the same backbone fold as the other alpha4/7-conotoxin structures, supporting the notion that this conotoxin cysteine framework and spacing give rise to a conserved fold. The surface charge distribution of [Tyr15]EpI is similar to that of PnIA and PnIB but is likely to be different from that of MII, suggesting that [Tyr15]EpI and MII may have different binding modes for the same receptor subtype. |
==About this Structure== | ==About this Structure== | ||
| - | 1A0M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Conus_episcopatus Conus episcopatus] with NH2 as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1A0M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Conus_episcopatus Conus episcopatus] with <scene name='pdbligand=NH2:'>NH2</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A0M OCA]. |
==Reference== | ==Reference== | ||
| Line 13: | Line 13: | ||
[[Category: Conus episcopatus]] | [[Category: Conus episcopatus]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Alewood, P | + | [[Category: Alewood, P F.]] |
| - | [[Category: Blessing, R | + | [[Category: Blessing, R H.]] |
| - | [[Category: Hu, S | + | [[Category: Hu, S H.]] |
| - | [[Category: Lewis, R | + | [[Category: Lewis, R J.]] |
[[Category: Loughnan, M.]] | [[Category: Loughnan, M.]] | ||
| - | [[Category: Martin, J | + | [[Category: Martin, J L.]] |
[[Category: Miller, R.]] | [[Category: Miller, R.]] | ||
| - | [[Category: Weeks, C | + | [[Category: Weeks, C M.]] |
[[Category: NH2]] | [[Category: NH2]] | ||
[[Category: a-conotoxin]] | [[Category: a-conotoxin]] | ||
| Line 27: | Line 27: | ||
[[Category: neurotoxin]] | [[Category: neurotoxin]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:39:31 2008'' |
Revision as of 09:39, 21 February 2008
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1.1 ANGSTROM CRYSTAL STRUCTURE OF A-CONOTOXIN [TYR15]-EPI
Overview
Conotoxins are valuable probes of receptors and ion channels because of their small size and highly selective activity. alpha-Conotoxin EpI, a 16-residue peptide from the mollusk-hunting Conus episcopatus, has the amino acid sequence GCCSDPRCNMNNPDY(SO3H)C-NH2 and appears to be an extremely potent and selective inhibitor of the alpha3beta2 and alpha3beta4 neuronal subtypes of the nicotinic acetylcholine receptor (nAChR). The desulfated form of EpI ([Tyr15]EpI) has a potency and selectivity for the nAChR receptor similar to those of EpI. Here we describe the crystal structure of [Tyr15]EpI solved at a resolution of 1.1 A using SnB. The asymmetric unit has a total of 284 non-hydrogen atoms, making this one of the largest structures solved de novo by direct methods. The [Tyr15]EpI structure brings to six the number of alpha-conotoxin structures that have been determined to date. Four of these, [Tyr15]EpI, PnIA, PnIB, and MII, have an alpha4/7 cysteine framework and are selective for the neuronal subtype of the nAChR. The structure of [Tyr15]EpI has the same backbone fold as the other alpha4/7-conotoxin structures, supporting the notion that this conotoxin cysteine framework and spacing give rise to a conserved fold. The surface charge distribution of [Tyr15]EpI is similar to that of PnIA and PnIB but is likely to be different from that of MII, suggesting that [Tyr15]EpI and MII may have different binding modes for the same receptor subtype.
About this Structure
1A0M is a Single protein structure of sequence from Conus episcopatus with as ligand. Full crystallographic information is available from OCA.
Reference
The 1.1 A resolution crystal structure of [Tyr15]EpI, a novel alpha-conotoxin from Conus episcopatus, solved by direct methods., Hu SH, Loughnan M, Miller R, Weeks CM, Blessing RH, Alewood PF, Lewis RJ, Martin JL, Biochemistry. 1998 Aug 18;37(33):11425-33. PMID:9708977
Page seeded by OCA on Thu Feb 21 11:39:31 2008
