TABLE 1.
Levels of expression of the lipase and the lipase chaperone in E. coli and lipase activity
| Vectora | % Expression ofb:
|
Activity (U/g of cells)c | |
|---|---|---|---|
| Lipase | Chaperone | ||
| pT-E(preLip-Hp) | <1 | <1 | 171 |
| pT-preLip-Hp | <1 | <1 | 293 |
| pT-Lip-Hp | 40 | <1 | 40 |
| pT-ompALip-Hp | 40d | <1 | 547 |
| pT-preLip | <1 | 37 | |
| pT-LipHis | 40 | 0 | |
| pT-HpHis | <1 | ||
| pT-modHpHis | <1 | ||
| pT-Δ34HpHis | 10 | ||
| pT-Δ70HpHis | 10 | ||
| pT-ompAΔ34HpHis | 60d | ||
| pT-ompAΔ70HpHis | 40e | ||
Abbreviations: pre, native lipase signal sequence; ompA, ompA signal sequence; E, EcoRI fragment derived from pHES12; Lip, lipase gene; Hp, chaperone gene; Δ34 or Δ70, chaperone truncated by 34 or 70 amino-terminal amino acids, respectively; His, His6 tag; mod, 5′ end of chaperone gene (bp 1 to 241) replaced by a synthetic, codon-optimized nucleotide sequence.
Estimated by densiometry with Imagemaster VDS version 2.0 and given as a percentage of the level of total cellular protein.
Determined after 3 h of incubation with pNPP as the substrate following cell lysis.
The ompA leader sequence was processed from 50% of expressed ompAΔ34HpHis.
The ompA leader sequence was not processed.