Luminescence emission from Neurospora copper metallothionein. Time-resolved studies.
The luminescence lifetime of Cu-metallothionein from the fungus Neurospora crassa has been studied by the frequency-domain emission technique. Lifetimes of 10.3 and 3.4 microseconds have been found for the protein in the absence and in the presence of oxygen respectively. Binding of Hg(II) results in a quenching of the luminescence correlated to the shortening of lifetime to 0.3-0.4 microsecond. No quenching by oxygen is found for the Hg(II)-Cu-metallothionein adduct. By analogy to model compounds, luminescence emission is attributed to a triplet excited state of a Cu(I)-to-sulphur charge-transfer complex. The comparison of bimolecular quenching constants for O2 and acrylamide indicates a highly compact structure of the protein.
Beltramini
M
M
Department of Biology, University of Padova, Italy.
Giacometti
G M
GM
Salvato
B
B
Giacometti
G
G
Münger
K
K
Lerch
K
K
D008163:Luminescent Measurements; D008668:Metallothionein; D009491:Neurospora; D009492:Neurospora crassa; D011487:Protein Conformation; D013997:Time Factors
C007121:copper thionein; D008668:Metallothionein