Table 1.
Designed peptides and summary of biophysical data
| Heptad repeat sequencea abcdefg | Systematic name suffixb | Oligomer statec | DPH bindingd (KD,μM) | XRDe PDB accession codes | XRD oligomer state and structure type | |
| SV | SE | |||||
| ββ | ||||||
| VKEVAfA | -VV | 5.8 | 5.6 | Y (27 ± 10.9) | 6G65 | 6 (barrel) |
| IKEVAfA | -IV | 6.8 | 6.4 | Y (8 ± 2.0) | 6G66 | 7 (barrel) |
| VKEIAfA | -VI | 5.4 | 5.3 | Y (7 ± 1.9) | - | - |
| IKEIAfA | -II | 6.1 | 5.7 | Y (57 ± 9.5) | 6G67 | 8 (barrel) |
| Lβ | ||||||
| LKEIAfA | -LI | 6.3 | 5.8 | Y (21 ± 3.0) | 4PNA | 7 (barrel) |
| lKEIAfA | -deLI | 6.9 | 6.6 | Y (12 ± 3.0) | 6G6E | 7 (barrel) |
| LKEVAfA | -LV | 6.3 | 5.4 | N | - | - |
| βL | ||||||
| VKELAfA | -VL | 4.9 | 5.4 | N | - | |
| IKELAfS | -IL-Sg | 6.4 | 6.1 | N | 6G68 | 6 (collapsed) |
| IKELAfS | -IL-Sg-L17E | 5.9 | 5.9 | Yf (62 ± 7.2) | 6G69 | 7 (barrel) |
| LL | ||||||
| LKELAfA | -LL | 6.1 | 5.9 | N | 6G6A | 6 (collapsed) |
| LKELAfA | -LL-L17Q | 6.0 | 6.0 | N | 6G6B | 6 (collapsed) |
| LKELAfA | -LL-L17E | 6.1 | 5.8 | Yf (10 ± 6.9) 272 ± 64.9) | 6G6C | 6 (collapsed) |
| Aromatics (collapsed) | ||||||
| IKEFAfA | -IF | 5.7 | 6.3 | N | - | - |
| FKEIAfA | -FI | 5.7 | 5.7 | - | 6G6F | 6 (collapsed) |
| LKEFAfA | -LF | 5.8 | 5.9 | N | 6G6G | 8 (collapsed) |
aMain heptad repeat of each peptide. Amino acids are denoted by standard one-letter code; except l for 4,5-dehydro-leucine (deL). Repeating f positions are occupied from N to C terminus by Q, K, W and Q, respectively. Full sequences are given in Supplementary Table 1
bSequences are described as CC-Type2 with a unique suffix. CC-Type2-VI, CC-Type2-LI and CC-Type2-LV have been described previously as AVKEIA, CC-Hept and ALKEVA, respectively26
cOligomer state in solution determined by sedimentation velocity (SV) experiments from a single run fitted to c(s) distributions to 95% confidence limits, or sedimentation equilibrium (SE) experiments ran in triplicate and fitted to a single ideal species. The values are observed molecular weight divided by monomer mass
dYes (Y) or No (N) binding of DPH (1 μM) over a range of peptide concentrations (n ≥ 3) to give KD values and standard errors. Dissociation constants are quoted per peptide
eProtein crystallography, X-ray diffraction
fBinding to 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene p-toluenesulfonate (TMA-DPH) a cationic derivative of DPH