Applied Bioinformatics Course

Sequence analysis of spider toxin and antifungal peptide

Structural analysis of Huwentoxin-I (1QK6), a neurotoxic peptide isolated from the venom of the Chinese bird spider Selenocosmia huwena [Qu et al., 1997] shows a structural feature of three disulfide bridges and three beta-strands. Sequence alignment and structure superposition of 1HWT with seven other peptides including funnel web spider toxin, cono-toxin and sweet taste repressor confirms that the core of this small folding unit is an anti-parallel beta-sheet and three disulfide bridges. This motif is one of the smallest folding unit belongs to the cystine-knot super family [Pallaghy et al., 1994; Harrison et al., 1996]. The connectivity of three disulfide bridges remains the same despite of the variation of sequence length and similarity. Careful comparison of our anti-fungal peptide against these 8 peptides implies that AFP may belong to this folding unit. A three dimensional model of AFP was constructed based on the above assumption.

Ackowledgments

The modeling work was carried out at the Biomolecular Modeling Laboratory, Imperial Cancer Research Fund by a Royal Society project to J LUO. Fig. 1 and Fig. 2 were generated by the molecular graphics program PREPI [Islam, 1998]. Thanks to Dr Gert Vriend and Dr Michael Sternberg for helpful discussion.

3 spiders Pokeberry Pokeberry root 6 ICK mitif peptides 6 ICK mitif peptides
The pictures of spiders are from Liao-Zhi's thesis. The pictures of pokeberry are from the Internet.

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27 May 2017, J Luo, CBI, PKU, Beijing, China