1R1G

Crystal Structure of the Scorpion Toxin BmBKTtx1

Summary for 1R1G

• Entry DOI: 10.2210/pdb1r1g/pdb
• Related: 1Q2K
• Descriptor: Neurotoxin BmK37 (2 entities in total)
• Functional Keywords: siras from s atoms, scorpion toxin, bmbkttx1, reductive dimethylation, toxin
• Cellular location: Secreted {ECO:0000269|Ref: P83407
• Total number of polymer chains: 2
• Total formula weight: 7022.60

Authors

Szyk, A.,Lu, W.,Xu, C.,Lubkowski, J. (deposition date: 2003-09-23, release date: 2004-03-02, Last modification date: 2025-03-26)

Primary citation

Szyk, A.,Lu, W.,Xu, C.,Lubkowski, J.
Structure of the scorpion toxin BmBKTtx1 solved from single wavelength anomalous scattering of sulfur.
J.Struct.Biol., 145:289-294, 2004

PubMed Abstract: 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.

PubMed: 14960379
DOI: 10.1016/j.jsb.2003.11.012

Experimental method

X-RAY DIFFRACTION (1.72 Å)