Fig. 3. Design of peptide CD4-PP, a cyclo-homodimer based on an improved KR12 peptide (LL37 218-29 fragment) containing activating mutations Q5A and D9K (shown in green). The optimized KR12 Q5A, D9K was used to produce a backbone cyclized anti-parallel homodimer. The flexible linker G/CPGG (shown in blue) was used to join the identical α-helical segments.96 The resulting cyclic peptide CD4-PP displayed 16-fold higher antibacterial activity compared to KR-12 against P. aeruginosa and S. aureus, and 8-fold increased fungicidal activity against C. albicans.96.
