Three-dimensional structure of BmP03 from venom of scorpion Buthus martensii Karsch

From the venom of scorpion Buthus martensii Karsch, a short peptide (BmP03, 28 amino acid residues) was isolated, characterized and tested as a weak i nhibitor of K+ channel. In this paper, the solution structure of BmP03 was determined by 2D H-1 NMR spectroscopy and molecular modeling calculations. The conformation of BmP03 is composed of a short alpha - helix (Cys3 - Gly1 2) and a two - strand antiparallel beta- sheet (Asn16 - Cys19, Cys24 - Asn2 7). There are three disulfide bridges (Cys3 - Cys19, Cys6 - Cys24, Cys10 - Cys26) connecting the alpha - helix and beta - sheet. Asp20 to Val23 residu es form a type II turn linking the two strands. Structural and electrostati c potential comparison between BmP03 and its analogues were also presented.