SITE-SPECIFIC, KINETICALLY INERT CONJUGATION OF LABELS AND/OR CARRIERS TO TARGET MOLECULES SUCH AS HIS-TAGGED PROTEINS VIA METAL COMPLEX REAGENTS

The present invention relates to means and methods for conjugating/ attaching target molecules such as proteins to a label and/or carrier. Specifically, the present invention provides a complex comprising a metal cation coordinating (i) nitrate as a metal cation ligand and (ii) a metal cation chelating domain comprising a chelating ligand and a label and/or carrier. This complex can be used for attaching a label and/or a carrier to a target molecule, preferably a protein. The attachment of the label or carrier via the complex of the invention involves the replacement of the metal cation ligand with a coordinating group of the target molecule so that a product complex with the target molecule as primary ligand in the coordination sphere of the metal cation is formed. Accordingly, the present invention also provides for uses and methods involving the attachment of a label and/or carrier to a target molecule. Also provided are the products obtained by the labeling and or carrier-attaching methods of the inventio