Conformation of uncomplexed natural antamanide crystallized from CH₃CN/H₂O

Abstract

Natural antamanide, a cyclic decapeptide from Amanita phalloides, has been shown to have the same conformation for the backbone and comparable side groups as the biologically active synthetic [Phe⁴, Val⁶]antamanide. Packing in the crystal is quite different for the two compounds. Large channels with a polar lining are formed in the crystals of [Phe⁴, Val⁶]antamanide, whereas in natural antamanide large channels in the crystal are completely surrounded by the lipophilic side groups of the Pro, Phe, and Ala residues. Antamanide, C₆₄H₇₈N₁₀O₁₀·8H₂O·X, crystallizes in space group P2₁2₁2₁ with a = 15.88 Å, b = 34.88 Å, and c = 13.61 Å.

• bound water
• solvent channels
• hydrogen bonds
• x-ray analysis