TABLE 3.
Dichroic ratios, R, and order parameters, P2, of the lipid and peptide bands from DMPS + gramicidin A membranes
| Sym CH2
|
Asym CH2
|
C=O
|
Amide I
|
Amide A
|
|||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| T (°C)* | R | P2 | R | P2 | R | P2 | R | P2 | R | P2 | |
| Dried | 10 | 1.11 | 0.47 | 1.12 | 0.47 | 1.17 | 0.44 | 1.94 | −0.02 | 1.92 | −0.03 |
| 60 | 1.12 | 0.47 | 1.13 | 0.46 | 1.20 | 0.42 | 1.99 | 0.0 | – | – | |
| Rehydrated | 10 | 1.09 | 0.49 | 1.10 | 0.48 | 1.21 | 0.41 | 2.50 | 0.17 | – | – |
| 24 | 1.18 | 0.43 | 1.20 | 0.42 | 1.24 | 0.39 | 2.63 | 0.21 | – | – | |
| 50 | 1.30 | 0.36 | 1.16 | 0.44 | 1.30 | 0.35 | 3.03 | 0.31 | – | – | |
| 60 | 1.26 | 0.38 | 1.30 | 0.36 | 1.33 | 0.34 | 3.23 | 0.36 | – | – | |
Shown are the dichroic ratios, R, and order parameters, P2, of the lipid (CH2 symmetric and asymmetric stretch, and carbonyl stretch) and peptide (amideI and A) bands from DMPS + gramicidin A (10:1 mol/mol) membranes.
*
Order parameters, 〈P2(cos γ)〉, are calculated from Eq. 1, with orientations, Θ, of the transition moment given in Materials and Methods (see also Theoretical Background). For the amide A band, the mean effective orientation of the transition moment is calculated from the order parameters obtained from the amide I band in Tables 2–5, ΘA = 27°. The order of the entries corresponds to the chronology of the measurements.