Table II.
Recovery of the Native hNBD1 After Detergent Removala
| Detergent and incubation time | Detergent concentration | Concentration recovery (%)b | Calorimetric enthalpy (%)c | Combined recovery (%) |
|---|---|---|---|---|
| no detergent | 93 ± 7 | 100 | 93 ± 7 | |
| DDM, 4 hrs | 20 mM (1% w/v, 111× CMC) | 98.5 ± 0.7 | 101 ± 1 | 99 ± 1 |
| DDM, 20 hrs | 20 mM (1% w/v, 111× CMC) | 81 ± 23 | 95 ± 4 | 77 ± 22 |
| DMNG, 4 hrs | 20 mM (1.9% w/v, 833× CMC) | 95 ± 4 | 101 ± 6 | 96 ± 7 |
| DMNG, 20 hrs | 20 mM (1.9% w/v, 833× CMC) | 95 ± 8 | 100 ± 8 | 95 ± 11 |
| LMNG, 4 hrs | 20 mM (2% w/v, 2020× CMC) | 99 ± 4 | 104 ± 1 | 103 ± 4 |
| LMNG, 20 hrs | 20 mM (2% w/v, 2020× CMC) | 96 ± 3 | 100 ± 4 | 96 ± 5 |
| LPG14, 4 hrs | 4 mM (0.19% w/v, 36× CMC) | 47 ± 6 | 99 ± 4 | 47 ± 6 |
| LPG14, 4 hrs | 10 mM (0.48% w/v, 90× CMC) | 55 ± 10 | 48 ± 4 | 26 ± 5 |
| LPG14, 20 hrs | 4 mM (0.19% w/v, 36× CMC) | 16 ± 4 | 74 ± 6 | 12 ± 3 |
| PFO, 4 hrs | 2 mM (0.09% w/v, 0.2× CMC) | 13 ± 2 | 57 ± 5 | 7 ± 1 |
| PFO, 4 hrs | 20 mM (0.9% w/v, 2× CMC) | 1 ± 1 | 0 | 0 |
| DDM/LPG14 1(1:1), 4 hrs | 10 mM (0.5% w/v, 69× CMC) | 94 ± 12 | 102 ± 1 | 96 ± 12 |
| DDM/LPG14 (1:1), 20 hrs | 10 mM (0.5% w/v, 69× CMC) | 91 ± 13 | 88 ± 16 | 81 ± 18 |
| FC14, 2 hrs | 5 mM (0.19% w/v, 38× CMC) | 63.5 ± 0.7 | 70 ± 14 | 44 ± 9 |
| FC14, 2 hrs | 25 mM (0.95% w/v, 192× CMC) | 31 ± 6 | 35 ± 1 | 11 ± 2 |
| FC14, 20 hrs | 5 mM (0.19% w/v, 38× CMC) | 33 ± 4 | 27 ± 9 | 9 ± 3 |
| LPC14, 4 hrs | 25 mM (1.2% w/v, 301× CMC) | 70.5 ± 0.7 | 83 ± 2 | 59 ± 2 |
| LPC14, 20 hrs | 25 mM (1.2% w/v, 301× CMC) | 83 ± 3 | 81 ± 4 | 67 ± 4 |
| CHAPS, 4 hrs | 10 mM (0.6% w/v, 1.5× CMC) | 96 ± 6 | 99 ± 3 | 95 ± 7 |
| CHAPS, 20 hrs | 10 mM (0.6% w/v, 1.5× CMC) | 91 ± 3 | 97 ± 2 | 88 ± 3 |
| CHAPS, 4 hrs | 68 mM (4.2% w/v, 10× CMC) | 85 ± 16 | 96 ± 11 | 82 ± 18 |
| CHAPS, 20 hrs | 68 mM (4.2% w/v, 10× CMC) | 86 ± 18 | 92 ± 6 | 79 ± 17 |
a
Tmax of all the samples after detergent removal matches the no-detergent control sample, indicating the spin column effectively removes all detergents. Results were averages of two sets of experiments conducted with different batches of protein on different dates.
b
The loss of protein in the spin column is likely due to the irreversible association of the protein with some of the detergents. When the detergents were retained by the spin column, the protein molecules were retained with the detergents.
c
A lowered apparent molar enthalpy indicates the existence of some denatured NBD1 in the recovered samples from the spin column.