Fig. 1

Schematic chemical structures of molecules relevant to the conjugation reactions between TCO- and MTZ-groups. a General conjugation reaction scheme. b Compounds used as the components in the TCO – MTZ conjugation reactions. With respect to the protein molecules, only TCO- and MTZ-group containing spacer arms are drawn as detailed chemical structures. The “n” after the square brackets indicates either a repeat of units or the possible multiple conjugations