Quarter field resonance and integer-spin/half-spin interaction in the EPR of Thermus thermophilus ferredoxin. Possible new fingerprints for three iron clusters.
Biochim Biophys Acta
; 828(3): 369-74, 1985 Apr 29.
Article
em En
| MEDLINE
| ID: mdl-2985120
ABSTRACT
We describe two new characteristics of the EPR of the seven-iron containing ferredoxin from Thermus thermophilus. First, the reduced state of the 3Fe center, which has traditionally been considered to be EPR-silent, has been found to exhibit a delta m = 4 transition, which is unique for Fe-S centers. This signal is similar to that of high-spin Fe2+-EDTA and supports the suggestion that the ground electronic state of the 3Fe cluster is S = 2. Second, we have recorded the EPR spectrum of the fully reduced protein at 9 and 15 GHz and found that changes occur in the signal which are consistent with a weak electronic spin-spin interaction between the [4Fe-4S]+ (S = 1/2) and the reduced 3Fe center. A theoretical explanation is given for the observation of interaction signals with constant effective g values.
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Base de dados:
MEDLINE
Assunto principal:
Thermus
/
Espectroscopia de Ressonância de Spin Eletrônica
/
Ferredoxinas
Idioma:
En
Ano de publicação:
1985
Tipo de documento:
Article