Using a cell-bound immunogen, we have generated a monoclonal antibody, 3D5, that recognizes carboxy-terminal oligo-histidine tags (His tags) on a wide variety of proteins. From this monoclonal antibody, we have generated a single-chain fragment of the variable domains (scFv), a dimeric scFv-alkaline phosphatase fusion and an oligovalent scFv-display phage. The antibody in its various formats is an effective tool used in fluorescence-activated cell sorting analysis, the BIAcore method, Western blots and enzyme-linked immunosorbent assay (ELISA). Western blots and ELISAs can be developed directly by using crude extracts of E.coli cells that produce the scFv-alkaline phosphatase fusion, thus providing an inexhaustable and convenient supply of detection reagent. Alternatively, oligovalent scFv-displaying phage can be used directly from culture supernatants for this purpose. The dissociation constants, KD of the peptide KGGHHHHH (KD = 4 x 10(-7) M) and of imidazole (KD = 4 x 10(-4) M) were determined. Molecular modeling of the Fv fragment suggests the occurrence of two salt bridges between the protonated histidine side chains of the peptide and the acidic groups in the antibody, explaining why the antibody or the substrate may be eluted under mildly basic conditions.

Lindner, P., Bauer, K., Krebber, A., Nieba, L., Kremmer, E., Krebber, C., Honegger, A., Klinger, B., Mocikat, R. and Plückthun, A.
Specific detection of his-tagged proteins with recombinant anti-His tag scFv-phosphatase or scFv-phage fusions
Biotechniques 22, 140-9 (1997)

Blank, K., Lindner, P., Diefenbach, B. and Plückthun, A.

Self-immobilizing recombinant antibody fragments for immunoaffinity chromatography: Generic, parallel and scaleable protein purification

Protein Expression and Purification, in press

Kaufmann, M, Lindner, P:, Honegger, A., Blank, K., Tschopp, M., Capitani, G., Plückthun, A., Grütter, M.G.

Crystal Structure of the Anti-His Tag Antibody 3D5 Single-Chain Fragment Complexed to its Antigen

J.Mol.Biol, submitted.