1b7d

Publication Abstract from PubMed

The crystal structure of neurotoxin Ts1, a major component of the venom of the Brazilian scorpion Tityus serrulatus, has been determined at 1.7 A resolution. It is the first X-ray structure of a highly toxic anti-mammalian beta-toxin. The folding of the polypeptide chain of Ts1 is similar to that of other scorpion toxins. A cysteine-stabilised alpha-helix/beta-sheet motif forms the core of the flattened molecule. All residues identified as functionally important by chemical modification and site-directed mutagenesis are located on one side of the molecule, which is therefore considered as the Na+channel recognition site. The distribution of charged and non-polar residues over this surface determines the specificity of the toxin-channel interaction. Comparison to other scorpion toxins shows that positively charged groups at positions 1 and 12 as well as a negative charge at position 2 are likely determinants of the specificity of beta-toxins. In contrast, the contribution of the conserved aromatic cluster to the interaction might be relatively small. Comparison of Ts1 to weak beta-toxins from Centruroides sculpturatus Ewing reveals that a number of basic amino acid residues located on the face of the molecule opposite to the binding surface may account for the high toxicity of Ts1.

Crystal structure of neurotoxin Ts1 from Tityus serrulatus provides insights into the specificity and toxicity of scorpion toxins.,Polikarpov I, Junior MS, Marangoni S, Toyama MH, Teplyakov A J Mol Biol. 1999 Jul 2;290(1):175-84. PMID:10388565^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.