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Landon, C ; Sodano, P ; Cornet, B ; Bonmatin, JM ; Kopeyan, C ; Rochat, H ; Vovelle, F ; Ptak, M

Refined solution structure of the anti-mammal and anti-insect LqqIII scorpion toxin : Comparison with other scorpion toxins

Proteins-Structure Function and Genetics 28 (3) 360-374

par Administrateur - publié le

Abstract :

The solution structure of the anti-mammal and anti-insect LqqIII toxin from the scorpion Leiurus quinquestriatus quinquestriatus was refined and compared with other long-chain scorpion toxins, This structure, determined by H-1-NMR and molecular modeling, involves an a-helix (18-29) linked to a three-stranded ß-sheet (2-6, 33-39, and 43-51) by two disulfide bridges, The average RMSD between the 15 best structures and the mean structure is 0.71 Angstrom for C a atoms, Comparison between LqqIII, the potent anti-mammal AaHII, and the weakly active variant-3 toxins revealed that the LqqIII three-dimensional structure is closer to that of AaHII than to the variant-3 structure, Moreover, striking analogies were observed between the electrostatic and hydrophobic potentials of LqqIII and AaHII.