Table 5.
Typical membrane binding elements, calculated energies (ΔGcalc, kcal/mol) and membrane penetration depths (D, Å) for different categories of membrane-associated proteins (see Additional file 1)
| Category | Na | Binding elements | ΔGcalc (kcal/mol) | D |
| A. Extramembrane domains of transmembrane proteins | 29 | α-helices, loops | -2.4 to -30.8 | 2.3 to 12.5 |
| B. Integral monotopic | 6 | α helices, | -8.6 to -38.3 | 4 to 10 |
| C.1. Peripheral enzymes | 119 | α-helices, loops | -1.4 to -38.2 | 1 to 13 |
| C.2. Water-soluble carriers of non-polar substances | 42 | α-helices, loops, β-sheets | -2.2 to -20.7 | 2 to 8 |
| C.3. Membrane-targeting and other structural domains | 93 | loops, α-helices, bound lipids | -1.2 to -12.3 | 1 to 9 |
| C.4. Electron carriers | 24 | Loops | -1.2 to -7.5 | 1 to 5 |
| C.5. Polypeptide ligands (hormones, toxins, inhibitors) | 101 | β-sheets, α-helices, loops | -1.6 to -18.1 | 1 to 18 |
| C.6. Water-soluble forms of channel-forming polypeptides | 38 | α-helices, loops | -1.3 to -20.9 | 1 to 28 |
aNumber of different protein structures in the set.