Part:BBa_K4387987
Hemolysin A secretion system for E. coli
The hemolysin A secretion machinery is a one-step secretion system (T1SS), originally isolated from uropathogenic E. coli strains. [1] It comprises three main peptides, the inner membrane proteins HlyB and HlyD, and the outer membrane protein TolC. Together, these three proteins build a continuous channel through which originally the HlyA toxin is secreted in a one-step manner. Interestingly, the secretion signal is not found on the N-terminal site, instead it is found at the C-terminal end and the signal sequence is not removed during secretion. Scientists have identified the secretion signal and were able to secrete various proteins of different sizes with this secretion machinery. [1]
This composite part contains the 2 membrane proteins HlyB (BBa_K4387999) and HlyD (BBa_K4387998) necessary for the channel formation. TolC is not included because it is already genomically expressed in many E. coli strains. [1] The formation of the secretion machinery is regulated by the constitutive promoter BBa_J23100 together with the RBS BBa_B0030. For a successful secretion, the c-terminal HlyA-tag (BBa_K4387997) has to be fused to the end of the protein intended to be secreted.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12INCOMPATIBLE WITH RFC[12]Illegal NheI site found at 7
Illegal NheI site found at 30 - 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25INCOMPATIBLE WITH RFC[25]Illegal NgoMIV site found at 1160
Illegal AgeI site found at 1330 - 1000COMPATIBLE WITH RFC[1000]
References
- [1] Ruano-Gallego, D., Fraile, S., Gutierrez, C. et al. Screening and purification of nanobodies from E. coli culture supernatants using the hemolysin secretion system. Microb Cell Fact 18, 47 (2019). https://doi.org/10.1186/s12934-019-1094-0
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