High affinity digoxigenin binding proteins
Isolated polypeptides with steroid binding activity and methods for their use as therapeutics and detection agents are disclosed herein.
1. An isolated polypeptide comprising a polypeptide at least 95% identical along its entire length to the amino acid sequence selected from the group consisting of SEQ ID NOS:10-23 wherein the amino acid sequence is not the amino acid sequence of SEQ ID NO: 24, wherein the isolated polypeptide binds to one or more of digoxigenin, digitoxigenin, progesterone, and β-estradiol, and digoxin.
2. The isolated polypeptide of claim 1 , comprising a polypeptide at least 98% identical along its entire length to the amino acid sequence selected from the group consisting of SEQ ID NOS:10-23, wherein the amino acid sequence is not the amino acid sequence of SEQ ID NO: 24.
3. The isolated polypeptide of claim 1 , comprising a polypeptide at least 99% identical along its entire length to the amino acid sequence selected from the group consisting of SEQ ID NOS:10-23, wherein the amino acid sequence is not the amino acid sequence of SEQ ID NO: 24.
4. The isolated polypeptide of claim 1 , comprising the amino acid sequence selected from the group consisting of SEQ ID NOS:10-23.
5. The isolated polypeptide of claim 1 , further comprising a detectable tag.
6. A pharmaceutical composition, comprising one or more polypeptides of claim 1 and a pharmaceutically acceptable carrier.
7. A method for treating digoxin overdose and/or toxicity, comprising administering to a subject in need thereof an amount effective of the polypeptide of claim 4 to treat the digoxin toxicity.
8. A method for detecting digoxin, comprising contacting a sample of interest with the polypeptide of claim 1 under suitable conditions for binding the detectable polypeptide to digoxin present in the sample to form a polypeptide-digoxin binding complex, and detecting the polypeptide-digoxin binding complex.
9. A pharmaceutical composition, comprising one or more polypeptides of claim 2 and a pharmaceutically acceptable carrier.
10. A pharmaceutical composition, comprising one or more polypeptides of claim 3 and a pharmaceutically acceptable carrier.
11. A pharmaceutical composition, comprising one or more polypeptides of claim 4 and a pharmaceutically acceptable carrier.