**1.7 Tryptophan rich antimicrobial peptides**

The archetypical W rich peptide is the indolicin, this peptide comes from *Bos Taurus* neutrophils and is the result of proteolysis. Unlike the amphipathic alpha helical structure of the cecropin class of peptides, their linear structure (no disulfid bridges) has no particular secondary structure in water. Indolicin is globular and amphipathic in aqueous solution, while it adopts a wedge shape when in contact with micelles. Indolicin shows a high affinity for neutral POPC and anionic POPG vesicles(Hsu et al., 2005). The author suggests that the structure changes and the strong membrane affinity are key to the antimicrobial activity of indolicin (Ladokhin and White, 2001). Tryptophan rich AMP contains more than 25% of the aminoacid. Indolicin, the archetypical tryptophan rich antimicrobial peptide, has a globular secondary structure in water, but show a wedge shape when in contact with in lipid micelles (Rozek et al., 2000). This peptide has the ability to permeate bacterial membranes and, depending of its tridimensional shape, inhibits DNA synthesis by binding to it (Hsu et al., 2005).

Indolicin: H-ILPWKWPWWPWRR-NH2
