NMR studies of the variant-3 neurotoxin from Centruroides sculpturatus Ewing.
We report a preliminary high-resolution proton nuclear magnetic resonance characterization of the variant-3 toxin from the scorpion Centruroides sculpturatus Ewing (range Southwestern USA). This toxin assumes a well defined folded conformation in aqueous solutions at room temperature and undergoes reversible thermal denaturation. A number of amide hydrogens exhibit exchange life times varying from several minutes to several hours. A few tentative assignments of the low field aromatic CH resonances has been made on the basis of 2D-COSY and NOE experiments. The upfield shifts exhibited by Trp-47 suggest a unique microenvironment for this residue. The NMR data suggest that there is some degree of correlation between the solution structure of the variant-3 toxin and its crystallographic structure. Our studies provide a basis for a detailed elucidation of the structure-function relationships of these interesting scorpion toxins which bind to the sodium channels of excitable membranes and delay sodium current inactivation.
D000595:Amino Acid Sequence; D000818:Animals; D003461:Crystallography; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009498:Neurotoxins; D011487:Protein Conformation; D011489:Protein Denaturation; D012604:Scorpion Venoms
C035413:Centruroides toxin; D009498:Neurotoxins; D012604:Scorpion Venoms