Table 1.
Polar Face Substitutions of Positively Charged Residues in AMPs
| Peptide Namea | Net Charge | Sequenceb | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| With specificity determinants (Lys13/Lys16) | |||||||||||||
| 1 | 3 | 7 | 11 | 18 | 22 | 26 | |||||||
| KL | X1 | SLL | X2 | TLS | X3 | AKAAKL | X4 | TLL | X5 | ALS | X6 | ||
| D87(Lys1-6 Arg-1) | +9 | Ac-KL(Arg)SLL(Arg)TLS(Arg)AKAAKL(Arg)TLL(Arg)ALS(Arg)-amide | |||||||||||
| D84(Lys1-6 Lys-1) | +9 | Ac-KL(Lys)SLL(Lys)TLS(Lys)AKAAKL(Lys)TLL(Lys)ALS(Lys)-amide | |||||||||||
| D85(Lys1-6 Orn-1) | +9 | Ac-KL(Orn)SLL(Orn)TLS(Orn)AKAAKL(Orn)TLL(Orn)ALS(Orn)-amide | |||||||||||
| D86(Lys1-6 Dab-1) | +9 | Ac-KL(Dab)SLL(Dab)TLS(Dab)AKAAKL(Dab)TLL(Dab)ALS(Dab)-amide | |||||||||||
| D105(Lys1-6 Dap-1) | +9 | Ac-KL(Dap)SLL(Dap)TLS(Dap)AKAAKL(Dap)TLL(Dap)ALS(Dap)-amide | |||||||||||
| D101(Lys1Ser26-5 Lys-1) | +8 | Ac-KL(Lys)SLL(Lys)TLS(Lys)AKAAKL(Lys)TLL(Lys)ALSS-amide | |||||||||||
| D102(Lys1Ser26-5 Dab-1) | +8 | Ac-KL(Dab)SLL(Dab)TLS(Dab)AKAAKL(Dab)TLL(Dab)ALSS-amide | |||||||||||
| Without specificity determinants (Ala13/Ala16) | |||||||||||||
| 1 | 3 | 7 | 11 | 18 | 22 | 26 | |||||||
| KL | X1 | SLL | X2 | TLS | X3 | AAAAAL | X4 | TLL | X5 | ALS | X6 | ||
| D85(K13A/K16A)-(Lys1-6 Orn-1) | +7 | Ac-KL(Orn)SLL(Orn)TLS(Orn)AAAAAL(Orn)TLL(Orn)ALS(Orn)-amide | |||||||||||
| D86(K13A/K16A)-(Lys1-6 Dab-1) | +7 | Ac-KL(Dab)SLL(Dab)TLS(Dab)AAAAAL(Dab)TLL(Dab)ALS(Dab)-amide | |||||||||||
| D105(K13A/K16A)-(Lys1-6 Dap-1) | +7 | Ac-KL(Dap)SLL(Dap)TLS(Dap)AAAAAL(Dap)TLL(Dap)ALS(Dap)-amide | |||||||||||
D denotes that all amino acid residues in each peptide are in the D-conformation except for Dab and Dap which are in the L-conformation. Specificity determinants are positively charged residues in the center of the nonpolar face (Lys13/Lys16). Without specificity determinants means replacement with Ala residues (Ala13/Ala16) (Figure 2).
Peptide sequences are shown using the one-letter code for all amino acid residues except at X1, X2, X3, X4, X5, and (except for D101 and D102) X6, where the three-letter code is used. Ac denotes Nα-acetyl and amide denotes Cα-amide. Positions X1, X2, X3, X4, X5, and (except for D101 and D102) X6 are positively charged residues (Arg, Lys, Orn, Dab, and Dap) on the polar face of the amphipathic α-helix (Figure 1); −1 denotes 6 positively charged residues on the polar face at positions 3, 7, 11, 18, 22, and 26 or 5 positively charged residues on the polar face at positions 3, 7, 11, 18, and 22 (position 26 is substituted by Ser).