The anti-MRSA peptide landscape explored in this work (Figure We point out that it is possible to establish a direct SAR based on pairwise comparisons. For instance, in the peptide pair 1 (Figure ), the terminal phenylalanine (Phe / F) could be associated with their biological activity difference. This is in agreement with X-ray diffraction studies that indicate that the terminal Phe on peptide structures improves the stability of helical conformation . Furthermore, He et al.