Affinity tag nucleic acid and protein compositions and processes for using same

Abstract

The present invention concerns compositions and processes that use affinity tags for isolating, and detecting or quantifying analytes, including nucleic acids, proteins and polypeptides. Compositions include nucleic acid compositions and protein compositions with affinity binding pairs, including metal binding peptides and immobilized metals, or peptide affinity groups.

What is claimed is: 
     
         1 . A composition comprising:
 (i) a fusion antibody comprising an antibody portion and at least one affinity peptide portion at the amino terminus or the carboxyl terminus of said antibody portion, wherein said affinity peptide comprises a metal binding peptide or is one member of a peptide affinity group; and   (ii) a matrix comprising a metal or a second member of said affinity peptide group.   
     
     
         2 . The composition of  claim 1 , wherein the at least one affinity peptide comprises one member of a peptide affinity group and the matrix comprises the second member of the affinity peptide group. 
     
     
         3 . The composition of  claim 2 , wherein said peptide affinity group comprises: S-protein and S-peptide; Glutathione S-Transferase (GST) tag and Glutathione (GSH); Protein Kinase A catalytic subunit (PKA) recognition peptide and PKA; Hemagglutinin (HA) epitope tag peptide and HA; Ketosteroid Isomerase (KSI) tag and oligo Phe; Ketosteroid Isomerase (KSI) tag and oligo Leu; oligo Arg and oligo Glu; or oligo Arg and oligo Asp. 
     
     
         4 . The composition of  claim 1 , wherein the affinity peptide comprises a metal binding peptide and the matrix comprises a metal. 
     
     
         5 . The composition of  claim 4 , wherein said metal binding peptide comprises oligohistidine or an oligopeptide comprising the sequence HGGHHG (SEQ ID NO:1), SPHHG (SEQ ID NO:2), SPHHGGSPHHG (SEQ ID NO:3), HPHHG (SEQ ID NO:4), HPHHGGHPHHG (SEQ ID NO:5), SPHHGGHPHHG (SEQ ID NO:6), HPHHGGSPHHG (SEQ ID NO:7), KDHLIHNVHKEEHAHAHNK (SEQ ID NO:8), GHGLGHGHEQQHGLGHGHK (SEQ ID NO:10), or HGLGHGHEQQHGLGHGH (SEQ ID NO:9). 
     
     
         6 . The composition of  claim 1 , wherein the fusion antibody is bound to the matrix via the at least one affinity peptide portion. 
     
     
         7 . The composition of  claim 2 , wherein the fusion antibody is bound to the matrix via the at least one affinity peptide portion. 
     
     
         8 . The composition of  claim 3 , wherein the fusion antibody is bound to the matrix via the at least one affinity peptide portion. 
     
     
         9 . The composition of  claim 4 , wherein the fusion antibody is bound to the matrix via the at least one affinity peptide portion. 
     
     
         10 . The composition of  claim 5 , wherein the fusion antibody is bound to the matrix via the at least one affinity peptide portion. 
     
     
         11 . A fusion antibody comprising:
 an antibody portion and at least one affinity peptide portion at the amino terminus or the carboxyl terminus of said antibody portion, wherein said affinity peptide comprises a metal binding peptide or is one member of a peptide affinity group.   
     
     
         12 . The fusion antibody of  claim 11 , wherein the at least one affinity peptide comprises one member of a peptide affinity group. 
     
     
         13 . The fusion antibody of  claim 12 , wherein said peptide affinity group comprises: S-protein and S-peptide; Glutathione S-Transferase (GST) tag and Glutathione (GSH); Protein Kinase A catalytic subunit (PKA) recognition peptide and PKA; Hemagglutinin (HA) epitope tag peptide and HA; Ketosteroid Isomerase (KSI) tag and oligo Phe; Ketosteroid Isomerase (KSI) tag and oligo Leu; oligo Arg and oligo Glu; or oligo Arg and oligo Asp. 
     
     
         14 . The fusion antibody of  claim 11 , wherein the affinity peptide comprises a metal binding peptide. 
     
     
         15 . The fusion antibody of  claim 14 , wherein said metal binding peptide comprises oligohistidine or an oligopeptide comprising the sequence HGGHHG (SEQ ID NO:1), SPHHG (SEQ ID NO:2), SPHHGGSPHHG (SEQ ID NO:3), HPHHG (SEQ ID NO:4), HPHHGGHPHHG (SEQ ID NO:5), SPHHGGHPHHG (SEQ ID NO:6), HPHHGGSPHHG (SEQ ID NO:7), KDHLIHNVHKEEHAHAHNK (SEQ ID NO:8), GHGLGHGHEQQHGLGHGHK (SEQ ID NO:10), or HGLGHGHEQQHGLGHGH (SEQ ID NO:9).