Steve Ealick's Research Group
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Steve Ealick's Research Group |
Scorpion Protein Toxin (Variant-2)
PDB files:
1JZA (space group P3221)
1JZB
(P3121)
Description:
Variant-2 scorpion toxin from Centruroides sculpturatus Ewing (CSE-v2) is a 66-amino acid protein, which was grown using seeding techniques. As in most scorpion toxins, the structure is stabilized by four disulfide bridges. The crystals display a temperature-dependent, reversible phase transition near room temperature. At room temperature, the space group is P3221 with a = 48.8 Å and c = 43.7 Å, and with one molecule per asymmetric unit. Below 4°C the crystals change to P3121 with two molecules in the asymmetric unit. At the lower temperature, a remains the same, but there is an approximate doubling of the c axis but with c' (approximately equal to 2c) = 87.2 Å.
| CsE-v2 is a compact globular protein with approximate dimensions of 25 x 32 x 36 Å). CsE-v2 contains one alpha helix and a three-stranded antiparallel beta sheet. The alpha helix is connected to the middle strand of the beta sheet by a pair of disulfide bonds. The longer outer strand of the beta sheet is linked to the long loop prior to the alpha helix by another disulfide bond. The fourth disulfide bond limits the flexibility of the C-terminus.
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References:
Cook WJ, Zell A, Watt DD, and Ealick SE. Structure of Variant 2 Scorpion Toxin From Centruroides sculpturatus Ewing. Protein Science 11:479-486 (2002).
Ealick SE, Cook WJ, Fontecilla-Camps JC, Suddath FL, Bugg CE, and Watt DD. Preliminary X-ray Investigation of Variant-2 Scorpion Toxin from Centruroides sculpturatus Ewing: Evidence of a Reversible Transition Between Crystal Forms. J. Biol. Chem. 269(19):12081-12083 (1984).
