Secondary structure determination for alpha-neurotoxin from Dendroaspis polylepis polylepis based on sequence-specific 1H-nuclear-magnetic-resonance assignments |
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Authors: | A M Labhardt E H Hunziker-Kwik K Wüthrich |
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Affiliation: | Institut für Molekularbiologie und Biophysik, Eidgen?ssische Technische Hochschule-H?nggerberg, Zürich, Switzerland. |
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Abstract: | Sequence-specific assignments are presented for the polypeptide backbone protons and a majority of the amino-acid-side-chain protons of alpha-neurotoxin from Dendroaspis polylepis polylepis, and individual amide proton-exchange rates with the solvent are reported. The secondary structure and the hydrogen-bonding patterns in the regular secondary structure elements are deduced from nuclear Overhauser effects and the sequence locations of the slowly exchanging amide protons. The molecule includes a three-stranded antiparallel beta-sheet, and there are indications that two additional short chain segments are arranged in an antiparallel beta-sheet. These structural elements are similar, but not identical, to either the secondary structure reported for erabutoxin b in single crystals, or the solution structure of cytotoxin CTXIIb from Naja mossambica mossambica. |
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