1JZA

Crystal Structure of Variant 2 Scorpion Toxin from Centruroides sculpturatus Ewing

Summary for 1JZA

• Entry DOI: 10.2210/pdb1jza/pdb
• Related: 1JZB
• Descriptor: NEUROTOXIN 2 (2 entities in total)
• Functional Keywords: scorpion toxin, noncrystallographic symmetry, toxin
• Biological source: Centruroides sculpturatus (bark scorpion)
• Cellular location: Secreted : P01493
• Total number of polymer chains: 2
• Total formula weight: 14364.22

Authors

Cook, W.J.,Zell, A.,Watt, D.D.,Ealick, S.E. (deposition date: 2001-09-14, release date: 2002-02-27, Last modification date: 2024-11-20)

Primary citation

Cook, W.J.,Zell, A.,Watt, D.D.,Ealick, S.E.
Structure of variant 2 scorpion toxin from Centruroides sculpturatus Ewing.
Protein Sci., 11:479-486, 2002

PubMed Abstract: Centruroides sculpturatus Ewing variant 2 toxin (CsE-v2) is a neurotoxin isolated from the venom of a scorpion native to the Arizona desert. The structure of CsE-v2 was solved in two different crystal forms using a combination of molecular replacement and multiple isomorphous replacement techniques. Crystals of CsE-v2 display a temperature-dependent, reversible-phase transition near room temperature. At lower temperature the space group changes from P3(2)21 to P3(1)21 with an approximate doubling of the C-axis. The small-cell structure, which has one molecule per asymmetric unit, has an R factor of 0.229 at 2.8 A resolution. The large-cell structure has two molecules per asymmetric unit and was refined at 2.2 A resolution to an R factor of 0.255. CsE-v2 is a rigid, compact structure with four intrachain disulfide bonds. The structure is similar to other long-chain beta neurotoxins, and the largest differences occur in the last six residues. The high-resolution structure of CsE-v2 corrects an error in the reported C-terminal sequence; the terminal tripeptide sequence is Ser 64-Cys 65-Ser 66 rather than Ser 64-Ser 65-Cys 66. Comparison of CsE-v2 with long-chain alpha toxins reveals four insertions and one deletion, as well as additional residues at the N and C termini. Structural alignment of alpha and beta toxins suggests that the primary distinguishing feature between the two classes is the length of the loop between the second and third strands in a three-strand beta sheet. The shorter loop in alpha toxins exposes a critical lysine side chain, whereas the longer loop in beta toxins buries the corresponding basic residue (either arginine or lysine).

PubMed: 11847271
DOI: 10.1110/ps.39202

Experimental method

X-RAY DIFFRACTION (2.2 Å)