Polypeptides for microbial detection
Polypeptides which can be activated to cause the formation of pores in a lipid membrane are disclosed. Also disclosed are polypeptide compositions for the detection of target microorganisms and methods of using said compositions.
1. An isolated polypeptide for the release of a substance from a lipid vesicle, the polypeptide comprising:
an activatable pore-forming portion which, when activated modulates the permeability of the lipid vesicle;
at least three phosphate groups wherein the hydrolysis of at least one of the phosphate groups activates the pore-forming portion of the polypeptide; and
an aliphatic group, wherein the isolated polypeptide comprises an N-terminal amino acid having an alpha amine group, wherein the aliphatic group is covalently attached to the alpha amine group of the isolated polypeptide.
2. The isolated polypeptide of claim 1 , wherein the polypeptide comprises at least one phosphorylated amino acid per eleven amino acids of the polypeptide.
3. The isolated polypeptide of claim 2 , wherein the polypeptide comprises at least one phosphorylated amino acid per six amino acids of the polypeptide.
4. A composition for detecting a target microorganism, comprising:
a lipid vesicle comprising a signaling element which generates a detectable signal; and
an isolated polypeptide according to claim 1 .
5. The composition of claim 4 , further comprises a recognition element.
6. The composition of claim 4 , further comprises a lysing agent.
7. The composition of claim 4 , further comprises an enzyme substrate.
8. The composition of claim 7 , wherein the signaling agent comprises an enzyme that reacts with the substrate to generate the detectable signal.