Part:BBa_K554002
HlyA secretion signal peptide
The HlyA is a signal peptide found in the C-terminal signal sequence of alpha-hemolysin (HlyA). It is used to target proteins for secretion via the Type I secretion pathway of gram-negative bacteria. Fusion of the HlyA signal peptide to the target protein may result in transport of the protein from the cytoplasm to the extracellular medium in a single step. HlyA, the signal sequence, seems to interact with the cytoplasmic region of the pre-formed HlyB–D complex. After the binding of the HlyA secretion signal by the HlyB–D complex, HlyD induces the interaction with TolC. To be effective, only the last 50-60 aminoacids of the C-terminal of Hly-A are required, so we can use it as a fusion protein that is attached to the interleukins (such as IL-12 and IL-10) and allows it to be secreted. Besides, HlyA is itself a weak antigen, turning it harmeless to the immune responses we are trying to interfere with.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
Usage and Biology
You can see a representation of this device acting in the schema below: HlyB gene and product are shown as a symbolic cilinder in orange.
Representation of device 3, the protein secretion system, in a Jedi bacteria that contains Device 1 (Adrenaline sensor/IL-12 producer). To export a protein, the bacteria must have the HlyD, HlyB and TolC proteins and the target protein must have a signal sequence (HlyA tail). In this case, the target protein to be secreted is IL-12.
A more realistic schema of ABC transport system is shown below:
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