Abstract
Detailed redox titrations monitored by EPR and UV-visible spectroscopies have been carried out on the dimeric ferredoxins I and II from Desulfovibrio vulgaris Miyazaki. Ferredoxin II contains a unique [4Fe-4S] cluster per subunit characterized by a midpoint potential of −417 mV at 24°C. The enthalpic and entropic contributions to the redox free energy variation of this cluster have been determined from the temperature dependence of the midpoint potential and compared to the data reported for other iron-sulfur proteins. The molecular arrangement of the two subunits is such that two [4Fe-4S]1+ clusters are magnetically coupled in the fully reduced state of the protein. Ferredoxin I contains one [3Fe-4S] and one [4Fe-4S] cluster per subunit, whose spectral and redox properties are very similar to those of the same clusters in ferredoxin III from Desulfovibrio africanus. The strong heterogeneity in the redox properties of the [3Fe-4S] center supports a bridging position between the N-terminal and C-terminal parts of the protein.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Biochemical and Biophysical Research Communications
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
