TABLE 1.

Energetic and structural parameters of PCs and their complexes with apoC-I

Lipids			Discoidal Complexes with ApoC-I
Name	Acyl chains sn:1, sn:2	Tc, °Ca	Thickness <l>, nmb	Diameter <d>, nmc	Arrhenius Activation Energy Ea, kcal/mold	δΔG*(37°), kcal/mole
DLPC	12:0, 12:0	−1	5.4 ± 0.3	17.6 ± 2.2	20 ± 5	−1.4
DMPC	14:0, 14:0	24	5.6 ± 0.3	15.5 ± 2.2	25 ± 5	0.0
DPPC	16:0, 16:0	41	6.1 ± 0.4	16.0 ± 2.2	30 ± 6	+1.5
DSPC	18:0, 18:0	54	6.4 ± 0.4	14.4 ± 3.0	36 ± 6	+2.9
POPC	16:0, 18:1	−5	5.6 ± 0.4	16.5 ± 6.0	20 ± 6	∼0
PLPC	16:0, 18:2	−20	5.5 ± 0.3	14.3 ± 5.0	18 ± 6	−0.2

DLPC, dilauroyl PC; DMPC, dimyristoyl PC; DPPC, dipalmitoyl PC; DSC, differential scanning calorimetry; DSPC, distearoyl PC; PLPC, palmitoyl-linoleoyl PC; POPC, palmitoyl-oleoyl PC. The values of E_a and ΔG* pertain to mole of cooperative unit involved in rHDL denaturation, which probably comprises one protein and several lipid molecules (see Discussion).

^aTemperature of gel-to-liquid crystal phase transition in pure PC (20).

^bSTD reflects experimental error in determination of disk thickness from the stacks observed by negative staining EM (such as those in Fig. 2A).

^cSTD reflects heterogeneity in the disk diameters determined by EM.

^dDetermined from the slopes of the Arrhenius plots (Fig. 4D) that were obtained from exponential fitting of the kinetic CD data, Θ₂₂₂(t) (such as those in Fig. 2). The accuracy in E_a determination reflects fitting errors and deviations among different data sets.

^eDifference in free energy of stability at 37°C as compared with apoC-I:DMPC disks. The values were obtained from linear extrapolation of the Arrhenius plots to 37°C (Fig. 4D); the accuracy in δΔG*(37°C) is ∼0.2 kcal/mol. For complexes with longer-chain PC (16 to 18 carbons) that show two-phase kinetics, the values for the first kinetic phase (corresponding to fusion of intact disks) are listed.