1r1g
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(New page: 200px<br /><applet load="1r1g" size="450" color="white" frame="true" align="right" spinBox="true" caption="1r1g, resolution 1.72Å" /> '''Crystal Structure of...)
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Revision as of 23:04, 20 November 2007
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Crystal Structure of the Scorpion Toxin BmBKTtx1
Overview
This report describes the crystal structure of the K(+) channel-blocking, toxin, BmBKTx1, isolated recently from the venom of the scorpion Buthus, martensi Karsch. This is only the second structure of the short-chain K(+), channel-blocking toxin from scorpion solved by means of X-ray, crystallography. Additionally, reductive dimethylation of folded BmBKTx1, employed to induce its crystallization and solution of the structure based, on the anomalous signal from the sulfur atoms make this example quite, unique. The monomer of BmBKTx1 is formed by 31 amino acid residues, including 6 cysteines connected in 3 disulfide bridges. Crystals of this, toxin belong to the space group P2(1) with two molecules present in the, asymmetric unit. The unit cell parameters are a = 21.40 A, b=39.70 A, c=29.37 A, and beta-94.13 grades. Based on the high-quality dataset, (anomalous signal) collected to the resolution 1.72A using the, conventional X-radiation generator (lambda Cu, K alpha = 1.5478 A), the, positions of sulfur atoms contributed by 12 cysteine residues have been, identified, and subsequent improvement of the experimental phases have, allowed structure solution. The final model was refined to the, crystallographic R-factor of 0.166. The methyl groups on several lysine, residues could be easily modeled into the electron density.
About this Structure
1R1G is a Single protein structure of sequence from [1]. Full crystallographic information is available from OCA.
Reference
Structure of the scorpion toxin BmBKTtx1 solved from single wavelength anomalous scattering of sulfur., Szyk A, Lu W, Xu C, Lubkowski J, J Struct Biol. 2004 Mar;145(3):289-94. PMID:14960379
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