Chapter 15: Light-activated Bioconjugate Complexes

This Chapter describes the various methods that are available for linking synthetic and biological light-activated or light-harvesting units to electron acceptors. The bioconjugate approaches discussed are divided into classical and non-classical approaches. The classical methods include modification of amine (lysine and α-N-terminus), cysteine, histidine, tyrosine and glutamine residues of the target proteins. Non-classical approaches discussed include recombinant methods for introducing non-natural amino acids, ‘click’ chemistry, carbonyl condensation and Michael addition reactions. Emphasis will be on examples from the literature that describe the bioconjugation of synthetic light-activated chromophores to redox proteins. The Chapter concludes with a few recent examples from the literature on light-activated chromophore-electron acceptor bioconjugates, including cytochrome complexes modified with Ru-organometallic complexes and Photosystem I modified with metallic nanoparticle electron acceptors.