Mechanism of formation, spectrum and reactivity of half-reduced eight-iron Clostridium pasteurianum ferredoxin in pulse-radiolysis studies and the non-co-operativity of the four-iron clusters.

نویسندگان

  • J Butler
  • R A Henderson
  • F A Armstrong
  • A G Sykes
چکیده

Reduction of fully oxidized Clostridium pasteurianum 8-Feox.,ox. ferredoxin by using pulse-radiolysis techniques yields the half-reduced species 8-Feox.,red. ferredoxin. The subsequent oxidation of 8-Feox.,red. ferredoxin with Co(NH3)5Cl2+ was studied. From a comparison with stopped-flow studies on the 2:1 Co(NH3)5Cl2+ oxidation of 8-Fered.,red. ferredoxin to the 8-Feox.,ox. form it is concluded that there is no redox co-operativity between the two 4-Fe centres in these reactions.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Formation of super-reduced Chromatium high-potential iron--sulphur protein in aqueous solution by pulse radiolysis.

Both the oxidized and reduced forms of Hipip (high-potential iron--sulphur protein) are reduced (approx. 30% yields) by eaq.- in a single-stage process, rate constants 1.7 x 10(10) and 1.8 x 10(10) M-1 . s-1 respectively, at 25 degrees C, pH 7.0 (5 mM-phosphate). Super-reduced Hipip, which is formed in the latter case, has a spectrum which closely resembles that of reduced ferredoxin, i.e. Fe4S...

متن کامل

Cluster orbital theory based on Mössbauer effect investigations of the (iron)4-sulfur clusters of Clostridium pasteurianum ferredoxin.

A cluster orbital theory is developed, which allows the calculation of Mössbauer spectra of oxidized and reduced ferredoxin of Clostridium pasteurianum under the conditions of low tempera­ ture (4.2 K) and high external magnetic field (H ex > IT ) . The calculations are based on the symmetry properties of the problem and the way in which these symmetries are reflected in the (iron)4-sulfur clus...

متن کامل

The Use of 13C Nuclear Magnetic Resonance of Aromatic Amino Acid Residues to Determine the Midpoint Oxidation-Reduction Potential of Each Iron-Sulfur Cluster of Clostridium acidi-urici and Clostridium pasteurianum Ferredoxins*

13C NMR of the aromatic residues of Clostridium acidi-urici [Phe*]ferredoxin (a chemically modified ferredoxin in which a phenylalanyl residue replaces a tyrosyl residue) and Clostridium pasteurianum ferredoxin permits one to distinguish and probe each iron-sulfur (Fe&*) cluster neighboring the aromatic residues within each protein. This is because the ring carbon resonance shifts of the phenyl...

متن کامل

Resonance Raman and Electron Paramagnetic Resonance Studies on Oxidized and Ferricyanide-treated Clostridium pasteurianum Ferredoxin VIBRATIONAL ASSIGNMENTS FROM 34S SHIFTS AND EVIDENCE FOR CONVERSION OF 4 TO 3 IRON- SULFUR CLUSTERS VIA OXIDATIVE DAMAGE*

Resonance Raman spectra are reported for oxidized ferredoxin from Clostridiumpasteurianum and for protein reconstituted with a4S2-, using 4579 A laser excitation. The spectra are of much higher quality than that previously reported, and the 34S shifts provide assignments of the Fe-S modes. After treatment with ferricyanide, the resonance Raman spectrum closely resembles that of the [3Fe-3S] pro...

متن کامل

Proton magnetic resonance study of ferredoxin from Clostridium pasteurianum.

Magnetic susceptibilities of both reduced and oxidized ferredoxin from Clostridium pasteurianum were obtained in solution. Whereas the reduced form exhibits a Curie law behavior, the magnetic susceptibility of oxidized ferredoxin in fact increases with temperature and suggests extensive antiferromagnetic exchange coupling between the component iron atoms. Contact-shifted resonances are observed...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • The Biochemical journal

دوره 183 2  شماره 

صفحات  -

تاریخ انتشار 1979