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Updated: Jun 9, 2026

Facile Protocol for the Synthesis of Self-assembling Polyamine-based Peptide Amphiphiles (PPAs) and Related Biomaterials
Published on: June 25, 2018
Solution structure of polytheonamide B, a highly cytotoxic nonribosomal polypeptide from marine sponge
Toshiyuki Hamada1, Shigeki Matsunaga, Masako Fujiwara
1Laboratory of Aquatic Natural Products Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan. thamada@sci.kagoshima-u.ac.jp
Abstract:
Polytheonamide B (pTB), a highly cytotoxic polypeptide, is one of the most unusual nonribosomal peptides of sponge origin. pTB is a linear 48-residue peptide with alternating D- and L-amino acids and contains a total of eight types of nonproteinogenic amino acids. To investigate the mechanisms underlying its cytotoxic activity, we determined the three-dimensional structure of pTB by NMR spectroscopy, structure calculation, and energy minimization. pTB adopts a single right-handed β(6.3)-helical structure in a 1:1 mixture of methanol/chloroform with a length of approximately 45 A and a hydrophilic pore of ca. 4 A inner diameter. These features indicate that pTB molecules form transmembrane channels that permeate monovalent cations as gramicidin A channels do. The strong cytotoxicity of pTB can be ascribed to its ability to form single molecule channels through biological membranes.
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