Computer simulation and structure analysis of polypeptide derivatives of cyclotriphosphazene

A quantum-chemical analysis and experimental investigation of the structure of poly(γ-methyl L-α-glutamate) and poly(γ-benzyl L-α-glutamate) linked with the triphosphazene ring via aminophenoxy groups were performed. The computer simulation showed that these compounds with a total degree of polymerization of amino acid sequences of n ≤ 60 are close to the rigid-rod conformation in struture, whereas the rod is distorted to the arch architecture at n > 60. According to X-ray data, the α helices of polypeptide segments are arranged into two-dimensional hexagonal packing. By means of the DSC technique, the glass transition associated with the freezing-out of the mobility of side chains was revealed, transitions to the mesophase were determined, and it was established that the helix type experiences a local change characteristic of poly(γ-benzyl glutamate) derivatives of cyclotriphosphazene in the solid state.