1QMW | pdb_00001qmw

Solution Structure of Alpha-Conotoxin Si

(2000) FEBS Lett 476: 287

• PubMed: 10913630 Search on PubMed
• DOI: https://doi.org/10.1016/s0014-5793(00)01724-5
• Primary Citation of Related Structures:  
  1QMW


• PubMed Abstract: 
  

  The nuclear magnetic resonance solution structure of alpha-conotoxin SI has been determined at pH 4.2. The 36 lowest energy structures show that alpha-conotoxin SI exists in a single major solution conformation and is stabilized by six hydrogen bonds. Comparisons are made between the SI solution structure and the solution and crystal structures of alpha-conotoxin GI. Surprisingly, a high degree of similarity between the backbone conformations of the GI crystal and the SI solution structures is seen in the region of lowest sequence homology, namely residues Gly-8 to Ser-12. This similarity is more surprising when considering that in SI a proline replaces the Arg-9 found in GI. The correspondence in conformation in this region provides the definitive evidence that it is the loss of the arginine basic charge at residue 9 which determines the differences in toxicity between GI and SI, rather than any changes in conformation induced by the cyclic proline residue.

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Organizational Affiliation: 

Molecular and Cellular Biology, St. Bartholomew's and the Royal London School of Medicine and Dentistry, University of London, UK.