Table 1.
peptidesb | hybrid Tm (°C)c | ΔHd (kcal/mol)c | Kd (nM) |
---|---|---|---|
(EKM)6 | 38 | 127 | 32 |
(EB2M)3/(SB2M)3 | 48/55 | 95/84 | 13/0.2d |
(EO2M)3/(SO2M)3 | 58/62 | 102/111 | 6/0.2d |
(EK2M)3/(SK2M)3 | 60/65 | 119/116 | 16/0.02d |
(EK2M)5/(SK2M)5 | 69/78 | 191/147 | 0.06/0.01d |
DNA was dT6C4T6 for all samples except (EK2M)5 and (SK2M)5, which used dT10C4T10.
(EKM)6 is bPNA while all others are bPNA+.
Thermal denaturation transition temperatures were obtained using UV, while enthalpy data were obtained via DSC.
Apparent Kd. Though data were highly reproducible and fit well to a 1:1 model, the lowest DNA concentration possible was well above fitted Kd (10 nM), leading to possible inaccuracies in Kd. All experimental conditions and full structures are provided in Supporting Information. B2M, O2M, and K2M indicate the amino acids 2-aminobutyric acid, ornithine, and lysine doubly alkylated on the side chain with an ethyl-melamine group (Scheme 1).