Supramolecular interactions between functional metal complexes and proteins.

This perspective illustrates the principles and applications of molecular recognition directed binding of transition metal complexes to proteins. After a brief introduction into non-covalent interactions and the importance of complementarity, the focus of the first part is on biological systems that rely on non-covalent forces for metal complex binding, such as proteins involved in bacterial iron uptake and the oxygen-storage protein myoglobin. The second part of the perspective will illustrate how the replacement of native with non-native metal-centres can give rise to artificial metalloenzymes with novel catalytic properties. Subsequently, examples of spectroscopic probes that exploit the characteristic photophysical properties of metal-complexes for the non-covalent labelling, visualisation and investigation of proteins will be described. Finally, the use of kinetically inert metal complexes as scaffolds in drug design will be discussed and it will be highlighted how the binding of metal ions or organometallic fragments to existing drugs or drug candidates can improve their activity or even alter their mode of action.