Role of the HoxZ Subunit in the Electron Transfer Pathway of the Membrane-Bound [NiFe]-Hydrogenase fromRalstonia eutrophaImmobilized on Electrodes

2011 ◽  
Vol 115 (34) ◽  
pp. 10368-10374 ◽  
Author(s):  
Murat Sezer ◽  
Stefan Frielingsdorf ◽  
Diego Millo ◽  
Nina Heidary ◽  
Tillman Utesch ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Electron Transfer Pathway ◽  
Membrane Bound

scholarly journals Customized exogenous ferredoxin functions as an efficient electron carrier

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Zhan Song ◽  
Cancan Wei ◽  
Chao Li ◽  
Xin Gao ◽  
Shuhong Mao ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Protein Interactions ◽  
Reaction System ◽  
Protein Protein Interactions ◽  
Electron Transfer Process ◽  
Potential Measurement ◽  
Electron Carrier ◽  
Electron Transfer Pathway ◽  
Biological Electron Transfer

AbstractFerredoxin (Fdx) is regarded as the main electron carrier in biological electron transfer and acts as an electron donor in metabolic pathways of many organisms. Here, we screened a self-sufficient P450-derived reductase PRF with promising production yield of 9OHAD (9α-hydroxy4-androstene-3,17-dione) from AD, and further proved the importance of [2Fe–2S] clusters of ferredoxin-oxidoreductase in transferring electrons in steroidal conversion. The results of truncated Fdx domain in all oxidoreductases and mutagenesis data elucidated the indispensable role of [2Fe–2S] clusters in the electron transfer process. By adding the independent plant-type Fdx to the reaction system, the AD (4-androstene-3,17-dione) conversion rate have been significantly improved. A novel efficient electron transfer pathway of PRF + Fdx + KshA (KshA, Rieske-type oxygenase of 3-ketosteroid-9-hydroxylase) in the reaction system rather than KshAB complex system was proposed based on analysis of protein–protein interactions and redox potential measurement. Adding free Fdx created a new conduit for electrons to travel from reductase to oxygenase. This electron transfer pathway provides new insight for the development of efficient exogenous Fdx as an electron carrier. Graphical Abstract

scholarly journals Customized exogenous ferredoxin functions as an efficient electron carrier

2021 ◽  
Author(s):  
Zhan Song ◽  
Cancan Wei ◽  
Chao Li ◽  
Xin Gao ◽  
Shuhong Mao ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Protein Interactions ◽  
Reaction System ◽  
Protein Protein Interactions ◽  
Potential Measurement ◽  
Electron Carrier ◽  
Electron Transfer Pathway ◽  
Reduction Activity ◽  
Biological Electron Transfer

Ferredoxin (Fdx) is regarded as the main electron carrier in biological electron transfer and acts as an electron donor in metabolic pathways of many organisms. Here, we screened a self-sufficient P450-derived reductase PRF with promising NADPH reduction activity and 9OHAD production yield and proved the importance of [2Fe-2S] clusters of Fdx-containing oxidoreductase in transferring electrons in steroidal conversion. The truncated Fdx domain in all oxidoreductases, together with mutagenesis data, further elucidated the indispensable role of [2Fe-2S] clusters in the electron transfer process. By adding the independent plant-type Fdx to the reaction system, the AD conversion rate have been significantly improved. A novel efficient electron transfer pathway of PRF+Fdx+KshA in the reaction system rather than KshAB complex system was proposed based on analysis of protein-protein interactions and redox potential measurement. Adding free Fdx created a new conduit for electrons to travel from reductase to oxygenase. This electron transfer pathway provides new insight for the development of efficient exogenous Fdx as an electron carrier.

The enzymatic basis for production by human neutrophils

1982 ◽  
Vol 60 (11) ◽  
pp. 1353-1358 ◽  
Author(s):  
Bernard M. Babior
Keyword(s):  
Electron Transfer ◽  
Chronic Granulomatous Disease ◽  
Human Neutrophils ◽  
Granulomatous Disease ◽  
Direct Route ◽  
Text Production ◽  
Membrane Bound ◽  
New Form

[Formula: see text] production is the first step in the generation of a group of powerful microbicidal oxidants by neutrophils. The production of [Formula: see text] is catalyzed by a membrane-bound, NADPH-preferring flavoprotein oxidase, a conclusion supported by much evidence including the discovery of a new form of chronic granulomatous disease caused by a mutation affecting that oxidase directly. Also involved in the [Formula: see text]-forming reaction is a b-type cytochrome; the role of this cytochrome is as yet undefined, though it does not appear to be on the direct route of electron transfer between NADPH and oxygen. It has been postulated that quinones too participate in the [Formula: see text]-forming reaction, but further work is necessary to define their role more fully.

scholarly journals The Quinone Binding Site in Escherichia coli Succinate Dehydrogenase Is Required for Electron Transfer to the Heme b

2006 ◽  
Vol 281 (43) ◽  
pp. 32310-32317 ◽  
Author(s):  
Quang M. Tran ◽  
Richard A. Rothery ◽  
Elena Maklashina ◽  
Gary Cecchini ◽  
Joel H. Weiner
Keyword(s):  
Escherichia Coli ◽  
Electron Transfer ◽  
Succinate Dehydrogenase ◽  
Radical Intermediate ◽  
Electron Transfer Pathway ◽  
Potentiometric Titrations ◽  
Quinone Binding ◽  
Enzyme Turnover ◽  
Succinate:Ubiquinone Oxidoreductase

We have examined the role of the quinone-binding (QP) site of Escherichia coli succinate:ubiquinone oxidoreductase (succinate dehydrogenase) in heme reduction and reoxidation during enzyme turnover. The SdhCDAB electron transfer pathway leads from a cytosolically localized flavin adenine dinucleotide cofactor to a QP site located within the membrane-intrinsic domain of the enzyme. The QP site is sandwiched between the [3Fe-4S] cluster of the SdhB subunit and the heme b556 that is coordinated by His residues from the SdhC and SdhD subunits. The intercenter distances between the cluster, heme, and QP site are all within the theoretical 14 Å limit proposed for kinetically competent intercenter electron transfer. Using EPR spectroscopy, we have demonstrated that the QP site of SdhCDAB stabilized a ubisemiquinone radical intermediate during enzyme turnover. Potentiometric titrations indicate that this species has an Em,8 of ∼60 mV and a stability constant (KSTAB) of ∼1.0. Mutants of the following conserved QP site residues, SdhC-S27, SdhC-R31, and SdhD-D82, have severe consequences on enzyme function. Mutation of the conserved SdhD-Y83 suggested to hydrogen bond to the ubiquinone cofactor had a less severe but still significant effect on function. In addition to loss of overall catalysis, these mutants also affect the rate of succinate-dependent heme reduction, indicating that the QP site is an essential stepping stone on the electron transfer pathway from the [3Fe-4S] cluster to the heme. Furthermore, the mutations result in the elimination of EPR-visible ubisemiquinone during potentiometric titrations. Overall, these results demonstrate the importance of a functional, semiquinone-stabilizing QP site for the observation of rapid succinate-dependent heme reduction.

Sign in / Sign up

Export Citation Format

Share Document