Proton nuclear magnetic resonance studies on huwentoxin-I from the venom of the spiderSelenocosmia huwena: 1. Sequence-specific1H-NMR assignments

The complete sequence-specific assignments of resonances in the¹H-NMR spectrum of huwentoxin-I from the Chinese bird spider,Selenocosmia huwena, is described. A combination of two-dimensional NMR experiments including 2D-COSY, 2D-NOESY, and 2D-TOCSY has been employed on samples of the toxin dissolved in D₂O and in H₂O for assignment purposes. Protons belonging to spin systems for each of the 33 amino acids were identified. The sequence-specific assignments were facilitated by the identification ofd _N connectivities on the fingerprint regions of the COSY and NOESY spectra and were supported by the identification ofd _NN andd _N connectivities in the TOCSY and NOESY spectra. These studies provide a basis for the determination of the solution-phase conformation of this toxin.Abbreviations HWTX-I huwentoxin-I - 2D two-dimensional - COSY 2D homonuclear correlation spectroscopy - NOE nuclear Overhauser enhancement - NOESY 2D nuclear Overhauser enhancement spectroscopy - TOCSY 2D total correlation spectroscopy - TPPI time-proportional phase incrementation - TSP sodium 3-(trimethyl-silyl)propionate-d4 - EDTA ethylenediaminetetraacetic acid