scholarly journals Dynamics of Redox State-Dependent Ferredoxin Structure and Electron-Transfer Complex Formation with Ferredoxin:NADP+ Reductase

2005 ◽  
Vol 45 (5) ◽  
pp. 253-258
Author(s):  
Keizo TESHIMA ◽  
Masami KUSUNOKI ◽  
Toshiharu HASE
Keyword(s):  
Electron Transfer ◽  
Complex Formation ◽  
Redox State ◽  
State Dependent ◽  
Electron Transfer Complex

Redox-State-Dependent Complex Formation between Pseudoazurin and Nitrite Reductase

2007 ◽  
Vol 129 (1) ◽  
pp. 226-233 ◽  
Author(s):  
Antonietta Impagliazzo ◽  
Anneloes J. Blok ◽  
Matthew J. Cliff ◽  
John E. Ladbury ◽  
Marcellus Ubbink
Keyword(s):  
Complex Formation ◽  
Nitrite Reductase ◽  
Redox State ◽  
State Dependent

scholarly journals Non-covalent forces tune the electron transfer complex between ferredoxin and sulfite reductase to optimize enzymatic activity

2016 ◽  
Vol 473 (21) ◽  
pp. 3837-3854 ◽  
Author(s):  
Ju Yaen Kim ◽  
Misaki Kinoshita ◽  
Satoshi Kume ◽  
Hanke GT ◽  
Toshihiko Sugiki ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Complex Formation ◽  
Enzymatic Activity ◽  
Electrostatic Interactions ◽  
Structural Rearrangement ◽  
Intermolecular Forces ◽  
Sulfite Reductase ◽  
Electrostatic Forces ◽  
Activity Curve ◽  
Electron Transfer Complex

Although electrostatic interactions between negatively charged ferredoxin (Fd) and positively charged sulfite reductase (SiR) have been predominantly highlighted to characterize complex formation, the detailed nature of intermolecular forces remains to be fully elucidated. We investigated interprotein forces for the formation of an electron transfer complex between Fd and SiR and their relationship to SiR activity using various approaches over NaCl concentrations between 0 and 400 mM. Fd-dependent SiR activity assays revealed a bell-shaped activity curve with a maximum ∼40–70 mM NaCl and a reverse bell-shaped dependence of interprotein affinity. Meanwhile, intrinsic SiR activity, as measured in a methyl viologen-dependent assay, exhibited saturation above 100 mM NaCl. Thus, two assays suggested that interprotein interaction is crucial in controlling Fd-dependent SiR activity. Calorimetric analyses showed the monotonic decrease in interprotein affinity on increasing NaCl concentrations, distinguished from a reverse bell-shaped interprotein affinity observed from Fd-dependent SiR activity assay. Furthermore, Fd:SiR complex formation and interprotein affinity were thermodynamically adjusted by both enthalpy and entropy through electrostatic and non-electrostatic interactions. A residue-based NMR investigation on the addition of SiR to 15N-labeled Fd at the various NaCl concentrations also demonstrated that a combination of electrostatic and non-electrostatic forces stabilized the complex with similar interfaces and modulated the binding affinity and mode. Our findings elucidate that non-electrostatic forces are also essential for the formation and modulation of the Fd:SiR complex. We suggest that a complex configuration optimized for maximum enzymatic activity near physiological salt conditions is achieved by structural rearrangement through controlled non-covalent interprotein interactions.

Inhibition of intramolecular electron transfer in ascorbate oxidase by Ag+: redox state dependent binding

2005 ◽  
Vol 99 (2) ◽  
pp. 600-605 ◽  
Author(s):  
Laura Santagostini ◽  
Michele Gullotti ◽  
James T. Hazzard ◽  
Silvana Maritano ◽  
Gordon Tollin ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Redox State ◽  
Ascorbate Oxidase ◽  
Intramolecular Electron Transfer ◽  
State Dependent

scholarly journals Electron Transfer Complex Formation between Oxygenase and Ferredoxin Components in Rieske Nonheme Iron Oxygenase System

Structure ◽  
2006 ◽  
Vol 14 (12) ◽  
pp. 1779-1789 ◽  
Author(s):  
Yuji Ashikawa ◽  
Zui Fujimoto ◽  
Haruko Noguchi ◽  
Hiroshi Habe ◽  
Toshio Omori ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Complex Formation ◽  
Nonheme Iron ◽  
Electron Transfer Complex
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