期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1971
卷号：68
期号：12
页码：3015-3020
DOI：10.1073/pnas.68.12.3015
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The coordination structure of the iron-sulfur complex in spinach ferredoxin and adrenodoxin is investigated by optical spectroscopy. The circular-dichroism and absorption spectra of these two-iron iron-sulfur proteins reveal weak electronic transitions in the near-infrared wavelength range, 0.8-2.5 {micro}m (12,500-4000 cm-1). On the basis of the low absorption intensities and large anisotropy factors, d [->] d transitions of the iron can be identified in the reduced proteins at about 4000 cm-1 and 6000 cm-1. The low energy of these one-center ligand-field transitions, together with the similarity to the ligand-field spectrum of the one-iron protein rubredoxin, leads to the conclusion that the reduced two-iron iron-sulfur proteins also contain a high-spin ferrous ion in a distorted tetrahedral site.
