Block copolypeptides. 1. Synthesis and solid state conformational studies

Triblock copolypeptides of gamma-benzyl L-glutamate (G) and L-leucine or L-valine of high molecular weight have been prepared. The solubilites and solution conformation were determined and compared with random copolymers of similar composition as well as the appropriate homopolypeptides. Characterization of the secondary structure in the solid state was undertaken as part of an investigation into the solid state properties of this new class of materials. Infrared and solid state measurements indicate that the G and L-leucine blocks assume an alpha-helical conformation and L-valine blocks a beta-sheet structure. Polarized infrared measurements showed the chain axis in oriented films to be parallel to the orientation direction. Further solid state characterization of the tertiary structure and mechanical properties of the block copolypeptides will be reported in succeeding papers.