Metal Abstraction Peptide (MAP) Tag and Associated Methods

Abstract

Compositions comprising a tripeptide having the sequence XC 1 C 2 ; wherein X is any amino acid such that XC 1 C 2 is capable of binding a metal in a square planar orientation or square pyramidal orientation or both; and wherein C 1 and C 2 are the same or different; and wherein C 1 and C 2 individually are chosen from a cysteine and a cysteine-like nonnatural amino acid, as well as metal-XC 1 C 2 complexes and methods for forming such complexes.

1 - 20 . (canceled) 
     
     
         21 . A complex comprising:
 a) an antibody; and   b) a hydrophilic group with a non-zero electric charge covalently bound to the antibody,   
       wherein the complex is more soluble in water than is the antibody alone. 
     
     
         22 . The complex of  claim 21 , wherein the hydrophilic group is bound to the antibody by an amide bond. 
     
     
         23 . The complex of  claim 21 , wherein the electric charge is a negative charge. 
     
     
         24 . The complex of  claim 21 , wherein the complex is isolated. 
     
     
         25 . The complex of  claim 21 , wherein the complex is synthetic. 
     
     
         26 . The complex of  claim 21 , wherein the hydrophilic group is poorly soluble in an organic solvent. 
     
     
         27 . The complex of  claim 21 , wherein the complex is more soluble at basic pH than at acidic pH. 
     
     
         28 . The complex of  claim 21 , wherein the complex has a density that is greater than the density of the antibody alone. 
     
     
         29 . The complex of  claim 21 , wherein the hydrophilic group is fluorescent. 
     
     
         30 . The complex of  claim 21 , wherein the hydrophilic group has a molecular mass that is less than 400 Daltons. 
     
     
         31 . The complex of  claim 21 , wherein the hydrophilic group has a molecular mass that is less than 340 Daltons. 
     
     
         32 . The complex of  claim 21 , wherein the complex has lower toxicity than does the antibody alone. 
     
     
         33 . The complex of  claim 21 , wherein the complex has a therapeutic application, wherein the complex is effective in the therapeutic application at a lower concentration than is the antibody alone. 
     
     
         34 . The complex of  claim 21 , wherein the complex further comprises a metal. 
     
     
         35 . The complex of  claim 34 , wherein the complex binds the metal at basic pH. 
     
     
         36 . The complex of  claim 34 , wherein the complex releases the metal at acidic pH. 
     
     
         37 . The complex of  claim 34 , wherein the hydrophilic group binds the metal. 
     
     
         38 . The complex of  claim 34 , wherein the complex binds the metal in a square geometry. 
     
     
         39 . The complex of  claim 38 , wherein the square geometry is square planar or square pyramidal. 
     
     
         40 . The complex of  claim 34 , wherein the metal is a radioisotope. 
     
     
         41 . The complex of  claim 34 , wherein the metal is zinc. 
     
     
         42 . The complex of  claim 34 , wherein the metal is platinum. 
     
     
         43 . The complex of  claim 34 , wherein the metal is nickel. 
     
     
         44 . The complex of  claim 34 , wherein the metal is copper. 
     
     
         45 . The complex of  claim 34 , wherein the metal is  62 Cu. 
     
     
         46 . The complex of  claim 21 , wherein the hydrophilic group comprises an amino acid sequence. 
     
     
         47 . The complex of  claim 46 , wherein the amino acid sequence comprises XC 1 C 2 , wherein X is any natural or unnatural amino acid or analogue thereof; and C 1  and C 2  are each independently a sulfur-containing amino acid. 
     
     
         48 . The complex of  claim 47 , wherein X is a basic amino acid. 
     
     
         49 . The complex of  claim 47 , wherein X is asparagine. 
     
     
         50 . The complex of  claim 47 , wherein X is histidine. 
     
     
         51 . The complex of  claim 47 , wherein at least one of C 1  and C 2  is cysteine. 
     
     
         52 . The complex of  claim 47 , wherein both C 1  and C 2  are cysteine.