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Light‐induced oxidation of iron atoms in a photosensitive nitrile hydratase
Author(s) -
Honda Jun,
Teratani Yoshitaka,
Kobayashi Yoshio,
Nagamune Teruyuki,
Sasabe Hiroyuki,
Hirata Akira,
Ambe Fumitoshi,
Endo Isao
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)81242-e
Subject(s) - nitrile hydratase , nitrile , chemistry , photochemistry , organic chemistry
The photoactivation process of a photosensitive nitrile hydratase (NHase) from Rhodococcus sp. N‐771 has been investigated by 57 Fe Mössbauer spectroscopy and magnetic susceptibility measurements in order to clarify the behavior of iron atoms in the enzyme. Mössbauer spectra of inactive NHase gave two symmetric‐doublet components indicating the presence of two iron species, while that of the active NHase gave a single symmetric doublet indicating the presence of a single iron species. Magnetic susceptibility measurements of the inactive and active HNase both showed small effective magnetic moments. These results led us to conclude that one of the two iron atoms incorporated in the NHase is oxidized during photoactivation, namely from a low spin ferrous to a low spin ferric state. This is the first observation of an intramolecular photooxidation phenomena involving iron in a single protein molecule.