Table 1. Solubility and secondary structure of binary alternating peptides.
| Sequence | 2° structure 1 | Soluble 2 | Purity |
|---|---|---|---|
| VSVS-CONH2 | -- 3 | 1.0 | crude / ~60% |
| SVSVS-CONH2 | -- | 1.0 | crude / ~60% |
| VSVSVS-CONH2 | -- | 1.0 | crude / ~60% |
| SVSVSVS-CONH2 | rc/β | 0.63 | crude / ~50% |
| VSVSVSVS-CONH2 | rc/β | -- 4 | crude / ~50% |
| SVSVSVSVS-CONH2 | β | 0.38 | crude / ~50% |
| SVSV-CONH2 | -- | 1.0 | HPLC / >95% |
| VSVSV-CONH2 | -- | 1.0 | HPLC / >95% |
| SVSVSV-CONH2 | β | 0.38 | HPLC / >95% |
| VSVSVSV-CONH2 | β | 0.05 | HPLC / >95% |
1 The secondary structure was estimated from the CD spectrum of the precipitate derived from a 0.2 mg/ml solution of peptide in 50 mM phosphate buffer pH 8. When the precipitate was transferred to the pH 4 buffer, the spectra were essentially the same.
2 The amount of the peptide in the supernatant and precipitate fractions was determined by hydrolysis (see Materials and Methods).
3 The CD spectra of samples indicated had no sufficient precipitate to be measured.
4 The quantitation of this sample was prevented by an interfering compound (HPLC).