Porous membrane-binding peptides
The present invention provides porous membrane-binding polypeptides, fusion proteins thereof, and methods for use of the polypeptides and fusion proteins in binding assays.
1. A polypeptide comprising the amino acid sequence of SEQ ID NO:1.
2. The polypeptide of claim 1 , comprising the amino acid sequence selected from the group consisting of SEQ ID NOS: 2-3.
3. A fusion protein, comprising (a) one or more polypeptide of claim 1 , and (b) a second polypeptide.
4. The fusion protein of claim 3 , wherein the second polypeptide binds to an analyte of interest.
5. The fusion protein of claim 4 , wherein the analyte of interest is a hemagglutinin protein.
6. The fusion protein of claim 5 , wherein the second polypeptide comprises a polypeptide having the amino acid sequence selected from the group consisting of SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, and SEQ ID NO:10.
7. The fusion protein of claim 3 , wherein the polypeptide of claim 1 and the second polypeptide are coupled through an amino acid linker.
8. The polypeptide of claim 1 , further comprising a tag linked to the polypeptide.
9. The polypeptide of claim 1 , wherein the tag comprises a detectable moiety, a diagnostic agent, or a therapeutic agent.
10. The fusion protein of claim 3 , further comprising a tag linked to the fusion protein.
11. The fusion protein of claim 10 , wherein the tag comprises a detectable moiety, a diagnostic agent, or a therapeutic agent.
12. The polypeptide of claim 1 impregnated in or immobilized to a porous solid support.
13. The polypeptide of claim 12 , wherein the porous solid support comprises nitrocellulose.
14. The fusion protein of claim 3 impregnated in or immobilized to a porous solid support.
15. The fusion protein of claim 14 , wherein the porous solid support comprises nitrocellulose.
16. A nucleic acid encoding the polypeptide of claim 1 .
17. A recombinant expression vector comprising the nucleic acid of claim 16 operatively linked to a suitable control sequence.
18. A host cell comprising the recombinant expression vector of claim 17 .
19. A method for diagnosing an influenza infection, or monitoring progression of an influenza infection, comprising contacting a biological sample from a subject suspected of having an influenza infection with a diagnostically effective amount of one or more fusion polypeptides of claim 6 , under conditions suitable for binding of the polypeptide to a viral HA protein present in the sample; removing unbound polypeptide and/or sample; and detecting polypeptide-viral HA binding complexes, where the presence of such binding complexes indicates that the subject has an influenza infection, or provides a measure of progression of an influenza infection.