SOLUTION STRUCTURE OF TERTIAPIN DETERMINED USING NUCLEAR-MAGNETIC-RESONANCE AND DISTANCE GEOMETRY

The solution structure of tertiapin, a 21-residue bee venom peptide, h as, been characterized by circular dichroism (CD), two-dimensional nuc lear magnetic resonance (NMR) spectroscopy, and distance geometry. A t otal of 21 lowest error structures were obtained from distance geometr y calculations. Superimposition of these structures shows that the bac kbone of tertiapin is very well defined. One type-I reverse turn from residue 4 to 7 and an alpha-helix from residue 12 to 19 exist in the s tructure of tertiapin. The alpha-helical region is best defined from b oth conformational analysis and structural superimposition. The overal l three-dimensional structure of tertiapin is highly compact resulting from side chain interactions. The structural information obtained fro m CD and NMR are compared for both tertiapin and apamin (ref. 3), anot her bee venom peptide. Tertiapin and apamin have some similar secondar y structure, but display different tertiary structures. (C) 1993 Wiley -Liss, Inc.