1sn4
From Proteopedia
(New page: 200px<br /><applet load="1sn4" size="450" color="white" frame="true" align="right" spinBox="true" caption="1sn4, resolution 1.3Å" /> '''STRUCTURE OF SCORPION...) |
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| - | [[Image:1sn4.jpg|left|200px]]<br /><applet load="1sn4" size=" | + | [[Image:1sn4.jpg|left|200px]]<br /><applet load="1sn4" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1sn4, resolution 1.3Å" /> | caption="1sn4, resolution 1.3Å" /> | ||
'''STRUCTURE OF SCORPION NEUROTOXIN BMK M4'''<br /> | '''STRUCTURE OF SCORPION NEUROTOXIN BMK M4'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The crystal structures of two group III alpha-like toxins from the | + | The crystal structures of two group III alpha-like toxins from the scorpion Buthus martensii Karsch, BmK M1 and BmK M4, were determined at 1.7 A and 1.3 A resolution and refined to R factors of 0.169 and 0.166, respectively. The first high-resolution structures of the alpha-like scorpion toxin show some striking features compared with structures of the "classical" alpha-toxin. Firstly, a non-proline cis peptide bond between residues 9 and 10 unusually occurs in the five-member reverse turn 8-12. Secondly, the cis peptide 9-10 mediates the spatial relationship between the turn 8-12 and the C-terminal stretch 58-64 through a pair of main-chain hydrogen bonds between residues 10 and 64 to form a unique tertiary arrangement which features the special orientation of the terminal residues 62-64. Finally, in consequence of the peculiar orientation of the C-terminal residues, the functional groups of Arg58, which are crucial for the toxin-receptor interaction, are exposed and accessible in BmK M1 and M4 rather than buried as in the classical alpha-toxins. Sequence alignment and characteristics analysis suggested that the above structural features observed in BmK M1 and M4 occur in all group III alpha-like toxins. Recently, some group III alpha-like toxins were demonstrated to occupy a receptor site different from the classical alpha-toxin. Therefore, the distinct structural features of BmK M1 and M4 presented here may provide the structural basis for the newly recognized toxin-receptor binding site selectivity. Besides, the non-proline cis peptide bonds found in these two structures play a role in the formation of the structural characteristics and in keeping accurate positions of the functionally crucial residues. This manifested a way to achieve high levels of molecular specificity and atomic precision through the strained backbone geometry. |
==About this Structure== | ==About this Structure== | ||
| - | 1SN4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mesobuthus_martensii Mesobuthus martensii] with ACT as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1SN4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mesobuthus_martensii Mesobuthus martensii] with <scene name='pdbligand=ACT:'>ACT</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SN4 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Mesobuthus martensii]] | [[Category: Mesobuthus martensii]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: He, X | + | [[Category: He, X L.]] |
| - | [[Category: Li, H | + | [[Category: Li, H M.]] |
| - | [[Category: Liu, X | + | [[Category: Liu, X Q.]] |
| - | [[Category: Wang, D | + | [[Category: Wang, D C.]] |
| - | [[Category: Zeng, Z | + | [[Category: Zeng, Z H.]] |
[[Category: ACT]] | [[Category: ACT]] | ||
[[Category: neurotoxin]] | [[Category: neurotoxin]] | ||
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[[Category: sodium channel inhibitor]] | [[Category: sodium channel inhibitor]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:03:19 2008'' |
Revision as of 13:03, 21 February 2008
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STRUCTURE OF SCORPION NEUROTOXIN BMK M4
Overview
The crystal structures of two group III alpha-like toxins from the scorpion Buthus martensii Karsch, BmK M1 and BmK M4, were determined at 1.7 A and 1.3 A resolution and refined to R factors of 0.169 and 0.166, respectively. The first high-resolution structures of the alpha-like scorpion toxin show some striking features compared with structures of the "classical" alpha-toxin. Firstly, a non-proline cis peptide bond between residues 9 and 10 unusually occurs in the five-member reverse turn 8-12. Secondly, the cis peptide 9-10 mediates the spatial relationship between the turn 8-12 and the C-terminal stretch 58-64 through a pair of main-chain hydrogen bonds between residues 10 and 64 to form a unique tertiary arrangement which features the special orientation of the terminal residues 62-64. Finally, in consequence of the peculiar orientation of the C-terminal residues, the functional groups of Arg58, which are crucial for the toxin-receptor interaction, are exposed and accessible in BmK M1 and M4 rather than buried as in the classical alpha-toxins. Sequence alignment and characteristics analysis suggested that the above structural features observed in BmK M1 and M4 occur in all group III alpha-like toxins. Recently, some group III alpha-like toxins were demonstrated to occupy a receptor site different from the classical alpha-toxin. Therefore, the distinct structural features of BmK M1 and M4 presented here may provide the structural basis for the newly recognized toxin-receptor binding site selectivity. Besides, the non-proline cis peptide bonds found in these two structures play a role in the formation of the structural characteristics and in keeping accurate positions of the functionally crucial residues. This manifested a way to achieve high levels of molecular specificity and atomic precision through the strained backbone geometry.
About this Structure
1SN4 is a Single protein structure of sequence from Mesobuthus martensii with as ligand. Full crystallographic information is available from OCA.
Reference
Crystal structures of two alpha-like scorpion toxins: non-proline cis peptide bonds and implications for new binding site selectivity on the sodium channel., He XL, Li HM, Zeng ZH, Liu XQ, Wang M, Wang DC, J Mol Biol. 1999 Sep 10;292(1):125-35. PMID:10493862
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