The bacterially produced antibiotic gramicidin A forms channels in cell membranes that allow the free diffusion of \( \mathrm{Na}^{+} \)and \( \mathrm{K}^{+} \)ions, thereby killing the cell. This peptide consists of a sequence of D- and L-amino acids. The sequence of a segment of five amino acids in gramicidin A is R-Gly-L-Ala-D-Leu-L-Ala-D-Val-R. Complete the structure below.