1agt: Difference between revisions
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'''SOLUTION STRUCTURE OF THE POTASSIUM CHANNEL INHIBITOR AGITOXIN 2: CALIPER FOR PROBING CHANNEL GEOMETRY'''<br /> | '''SOLUTION STRUCTURE OF THE POTASSIUM CHANNEL INHIBITOR AGITOXIN 2: CALIPER FOR PROBING CHANNEL GEOMETRY'''<br /> | ||
==Overview== | ==Overview== | ||
The structure of the potassium channel blocker agitoxin 2 was solved by | The structure of the potassium channel blocker agitoxin 2 was solved by solution NMR methods. The structure consists of a triple-stranded antiparallel beta-sheet and a single helix covering one face of the beta-sheet. The cysteine side chains connecting the beta-sheet and the helix form the core of the molecule. One edge of the beta-sheet and the adjacent face of the helix form the interface with the Shaker K+ channel. The fold of agitoxin is homologous to the previously determined folds of scorpion venom toxins. However, agitoxin 2 differs significantly from the other channel blockers in the specificity of its interactions. This study was thus focused on a precise characterization of the surface residues at the face of the protein interacting with the Shaker K+ channel. The rigid toxin molecule can be used to estimate dimensions of the potassium channel. Surface-exposed residues, Arg24, Lys27, and Arg31 of the beta-sheet, have been identified from mutagenesis studies as functionally important for blocking the Shaker K+ channel. The sequential and spatial locations of Arg24 and Arg31 are not conserved among the homologous toxins. Knowledge on the details of the channel-binding sites of agitoxin 2 formed a basis for site-directed mutagenesis studies of the toxin and the K+ channel sequences. Observed interactions between mutated toxin and channel are being used to elucidate the channel structure and mechanisms of channel-toxin interactions. | ||
==About this Structure== | ==About this Structure== | ||
1AGT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Leiurus_quinquestriatus_hebraeus Leiurus quinquestriatus hebraeus]. Full crystallographic information is available from [http:// | 1AGT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Leiurus_quinquestriatus_hebraeus Leiurus quinquestriatus hebraeus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AGT OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Hidalgo, P.]] | [[Category: Hidalgo, P.]] | ||
[[Category: Kasibhatla, C.]] | [[Category: Kasibhatla, C.]] | ||
[[Category: Krezel, A | [[Category: Krezel, A M.]] | ||
[[Category: Mackinnon, R.]] | [[Category: Mackinnon, R.]] | ||
[[Category: Wagner, G.]] | [[Category: Wagner, G.]] | ||
[[Category: potassium channel blocker]] | [[Category: potassium channel blocker]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:44:20 2008'' | ||
Revision as of 09:44, 21 February 2008
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SOLUTION STRUCTURE OF THE POTASSIUM CHANNEL INHIBITOR AGITOXIN 2: CALIPER FOR PROBING CHANNEL GEOMETRY
Overview
The structure of the potassium channel blocker agitoxin 2 was solved by solution NMR methods. The structure consists of a triple-stranded antiparallel beta-sheet and a single helix covering one face of the beta-sheet. The cysteine side chains connecting the beta-sheet and the helix form the core of the molecule. One edge of the beta-sheet and the adjacent face of the helix form the interface with the Shaker K+ channel. The fold of agitoxin is homologous to the previously determined folds of scorpion venom toxins. However, agitoxin 2 differs significantly from the other channel blockers in the specificity of its interactions. This study was thus focused on a precise characterization of the surface residues at the face of the protein interacting with the Shaker K+ channel. The rigid toxin molecule can be used to estimate dimensions of the potassium channel. Surface-exposed residues, Arg24, Lys27, and Arg31 of the beta-sheet, have been identified from mutagenesis studies as functionally important for blocking the Shaker K+ channel. The sequential and spatial locations of Arg24 and Arg31 are not conserved among the homologous toxins. Knowledge on the details of the channel-binding sites of agitoxin 2 formed a basis for site-directed mutagenesis studies of the toxin and the K+ channel sequences. Observed interactions between mutated toxin and channel are being used to elucidate the channel structure and mechanisms of channel-toxin interactions.
About this Structure
1AGT is a Single protein structure of sequence from Leiurus quinquestriatus hebraeus. Full crystallographic information is available from OCA.
Reference
Solution structure of the potassium channel inhibitor agitoxin 2: caliper for probing channel geometry., Krezel AM, Kasibhatla C, Hidalgo P, MacKinnon R, Wagner G, Protein Sci. 1995 Aug;4(8):1478-89. PMID:8520473
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