TABLE 3.
Levels and distribution of His6-containing fusion proteins in L. fermentum strains
| Vector type | Fusion protein (size in kDa) | Protein (mg/liter of culture)
|
Surface display efficiencyf (mean ± SD) | ||||
|---|---|---|---|---|---|---|---|
| Total (cell extract + supernatant)a | SDSb | Sonc | LiCld | SNe | |||
| Surface display | BspA-His6-CFTR (32) | 4.7 | 0.78 | 4.0 | 2.6 | 0.68 | 2.03 ± 0.01 |
| His6-CFTR-Rlp (19) | 1.1 | 0.47 | 0.71 | 0.04 | 0.37 | 10.01 ± 0.03 | |
| Secretion | Mlp-His6 (27) | 2.2 | 0.46 | 2.1 | 0 | 0.06 | ND |
| Mlp-His6-CFTR (328) | 12.0 | 1.7 | 1.2 | 0 | 10.3 | ND | |
a
Calculated by using the cell extract method which yielded the greatest amount of protein (either SDS or Son).
b
SDS, proteins extracted from cells by boiling in 2× SDS loading buffer.
c
Son, proteins extracted from cells by sonication.
d
LiCl, proteins extracted from cells by 5 M LiCl.
e
SN, proteins from supernatant.
f
Whole-cell ELISA results presented as the fold increase in OD405 signal per OD600 of cells ± over that obtained with wild-type L. fermentum BR11. The OD405 signal per OD600 of cells for L. fermentum BR11 was 0.0226 ± 0.0006. gND, not determined.