Sequence specific
Assignment of 1H-NMR Resonance and Determination of the Secondary
Structure of HWTX-II
SHU Qin1, LU Shan-Yun1, GU Xiao-Cheng1,
LIANG Song-Ping2*
( 1Life Science College, Peking University, Beijing 100871；2Life Science College, Hunan
Normal University, Changsha 410081, China )
Abstract
Huwentoxin-II (HWTX-II)is an insecticidal peptide purified from the venom of
spider Selenocosmia huwena. The structure of this toxin in solution
was investigated using 2D-NMR. The complete sequence-specific assignments of
proton resonance in the 1H-NMR spectra of HWTX-II were obtained by
analyzing a series of 2D spectrum, including COSY, DQF-COSY, TOCSY and NOESY.
All the backbone protons and side chain protons, except εNH2 protons
of Lys residues, were identified by dαN, dαδ, dNN
and dβN connectivities. The results provide a basis for further
determination of the solution conformation of HWTX-II. Furthermore the
secondary structure of HWTX-II was determined from NMR data. It contained
mainly extended conformation, especially a double-stranded anti-parallel
β-sheet with Trp27–Cys29 and Cys34–Lys36 at the C terminal, and it lacked
helix. These characters of the secondary structure of HWTX-II were similar to
those spider toxins which structure in solution had been reported.
Key words HWTX-II；2D-NMR；sequence-specific assignment；secondary structure
*Corresponding author：Tel,86-731-8872556；Fax,86-731-8861304；e-mail,[email protected]