The Pathway, Kinetics and Thermodynamics of Electron Transfer in Wild Type and Mutant Reaction Centers of Purple Nonsulfur Bacteria

2006 ◽  
pp. 527-557 ◽  
Author(s):  
Neal W. Woodbury ◽  
James P. Allen
Keyword(s):  
Electron Transfer ◽  
Reaction Centers ◽  
Purple Nonsulfur Bacteria ◽  
Wild Type ◽  
Kinetics And Thermodynamics

Lipids affect the charge stabilization in wild-type and mutant reaction centers of Rhodobacter sphaeroides R-26

1999 ◽  
Vol 26 (5) ◽  
pp. 465 ◽  
Author(s):  
László Nagy ◽  
Elfrida Fodor ◽  
Júlia Tandori ◽  
László Rinyu ◽  
Tibor Farkas
Keyword(s):  
Electron Transfer ◽  
Rhodobacter Sphaeroides ◽  
Electrostatic Interactions ◽  
Reaction Centers ◽  
Wild Type ◽  
Photosynthetic Membrane ◽  
Protein Ratio ◽  
Intracytoplasmic Membranes ◽  
In The Wild ◽  
Charge Stabilization

The effect of lipids on stabilization of electrons on the secondary quinone was studied in reaction centers (RC) of herbicide-sensitive and -resistant (L229Ile → Met) Rhodobacter sphaeroides R-26. The lipid concentration and the lipid/protein ratio of the intracytoplasmic membranes (ICM) were larger in the mutant RCs than in the wild-type. The free energy changes of Q A – Q B → Q A Q B – electron transfer were ΔG 0 = –57 meV, –69 meV, –85 meV for the wild-type and ΔG 0 = 0 meV, –15 meV, –46 meV for the mutant at pH = 8.0, in detergent, liposome and ICM, respectively. The differences in the stabilization energies of both strains decreased from the detergent via proteoliposome to chromatophore. We conclude that the energetics of the interquinone electron transfer depends on the environment of the reaction center. The steric and/or electrostatic interactions of the environment and Q B pocket can modulate the energetics of the charge stabilization over large distances. The interaction may have crucial importance on coupling the electron transport in the photosynthetic membrane to the anabolic/catabolic processes taking place in the cells.

scholarly journals Electron transfer by human wild-type and A287P mutant P450 oxidoreductase assessed by transient kinetics: functional basis of P450 oxidoreductase deficiency

2015 ◽  
Vol 468 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Yi Jin ◽  
Mo Chen ◽  
Trevor M. Penning ◽  
Walter L. Miller
Keyword(s):  
Electron Transfer ◽  
European Ancestry ◽  
Wild Type ◽  
Transient Kinetics ◽  
Skeletal Malformation ◽  
P450 Oxidoreductase ◽  
Sex Development ◽  
Cytochrome P450 Oxidoreductase ◽  
Flavin Binding ◽  
Human Wild Type

We show that the cytochrome P450 oxidoreductase (POR) A287P variant, which can lead to skeletal malformation and disordered sex development, found in 40% of patients of European ancestry is characterized by deficient flavin binding and impaired electron transfer from NADPH.

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