Poly (d trp-L Leu), poly (D Phe-L Leu) and poly (D Val-L Val-D Val-L Ala) as model polymers for the elucidation of the gramicidin a conformation

From infrared observations it is concluded that the conformation of poly (D Trp-L leu), poly (D Leu-L Trp), poly (D Phe-L leu) and poly (D val-L Val-D Val-L Ala) wich are model polymers of Gramicidin A is the same as one species of the antibiotic. Diffraction investigations indicate that poly-(D Phe-L Leu) and poly (D Val-L Val-D Val-L Ala) have a helical conformation which is most probably the pi DL 8 helix.