Oxidative quenching of luminescence from copper metallothionein

Cu(I) Luminescence from the Tetranuclear Cu4S4 Cofactor of a Synthetic 4-Helix Bundle

“…This luminescence has an excitation spectrum with a maximum at 275 nm and can be quenched by the addition of either ferricyanide, oxygen, or urea, which indicates that the emitting species is associated with the reduced Cu(I) state, has significant triplet character, and is quenched upon exposure to bulk solvent. Similar properties have been reported for Cu(I) derivatives of the metal-binding protein, metallothionein, , as well as to those of the copper responsive transcription factors, ACE1, AMT, and CopY, which all contain embedded thiolato metal-binding domains 1 Emission titration of C16C19-GGY by [Cu(CH 3 CN) 4 ]PF 6 .…”

Self‐Assembly of Functional Discrete Three‐Dimensional Architectures in Water

“…EXAFS data indicate atrigonally coordinated Cu-S 3 cluster exists within the metal binding site of metallothionein, where up to 12 Cu I ions can interact with 20 thiolate groups in the protein. [191,192] Oxidative quenching data revealed the Cu I cluster is an active redox centre for electron transfer,a nd introduction of such site into astable,well-understood coiledcoil motif should be possible.ACys-binding site was therefore engineered into ak nown coiled-coil sequence,a nd following the addition of aC u I salt resulted in the formation of at rigonal Cu 4 S 4 (N/O) 4 cluster bound within the core of a4stranded coiled-coil. [193] This complex displayed significant luminescence and when photoexcited underwent electron transfer to an umber of ruthenium ammine acceptors, providing an interesting foundation for synthetic electron transfer proteins.…”

Photoluminescence Properties of Multinuclear Copper(I) Compounds

“…The emission from Cu(I)-MT-2 complexes is dynamically quenched by solution dioxygen (k q × 10 9 M -1 s -1 ) without observable alteration of the solution CD spectrum. 59 This suggests that oxygen is serving to quench via energy transfer without significant oxidation of the ground state, and this and other properties were used to argue that the luminescent excited state is of triplet character. The presence of ferricyanide led to oxidative quenching of the Cu 12 -MT emission and concomitant disruption of the protein three-dimensional structure.…”