Effects of pathogenic mutations in membrane subunits of mitochondrial Complex I on redox activity and proton translocation studied by modeling in Escherichia coli

Mitochondrion ◽  
2015 ◽  
Vol 22 ◽  
pp. 23-30 ◽  
Author(s):  
Jukka Pätsi ◽  
Marko Kervinen ◽  
Laura Kytövuori ◽  
Kari Majamaa ◽  
Ilmo E. Hassinen
Keyword(s):  
Escherichia Coli ◽  
Complex I ◽  
Proton Translocation ◽  
Redox Activity ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Pathogenic Mutations

Reduction of Synthetic Ubiquinone QT Catalyzed by Bovine Mitochondrial Complex I Is Decoupled from Proton Translocation

Biochemistry ◽  
2016 ◽  
Vol 55 (3) ◽  
pp. 470-481 ◽  
Author(s):  
Kenji Okuda ◽  
Masatoshi Murai ◽  
Shunsuke Aburaya ◽  
Wataru Aoki ◽  
Hideto Miyoshi
Keyword(s):  
Complex I ◽  
Proton Translocation ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex

scholarly journals The specificity of mitochondrial complex I for ubiquinones

1996 ◽  
Vol 313 (1) ◽  
pp. 327-334 ◽  
Author(s):  
Mauro ESPOSTI DEGLI ◽  
Anna NGO ◽  
Gabrielle L. McMULLEN ◽  
Anna GHELLI ◽  
Francesca SPARLA ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Electron Transport ◽  
Complex I ◽  
Reductase Activity ◽  
Redox Activity ◽  
Mitochondrial Complex I ◽  
Transport Activity ◽  
Mitochondrial Complex ◽  
Potential Generation ◽  
Electron Transport Activity

We report the first detailed study on the ubiquinone (coenzyme Q; abbreviated to Q) analogue specificity of mitochondrial complex I, NADH:Q reductase, in intact submitochondrial particles. The enzymic function of complex I has been investigated using a series of analogues of Q as electron acceptor substrates for both electron transport activity and the associated generation of membrane potential. Q analogues with a saturated substituent of one to three carbons at position 6 of the 2,3-dimethoxy-5-methyl-1,4-benzoquinone ring have the fastest rates of electron transport activity, and analogues with a substituent of seven to nine carbon atoms have the highest values of association constant derived from NADH:Q reductase activity. The rate of NADH:Q reductase activity is potently but incompletely inhibited by rotenone, and the residual rotenone-insensitive rate is stimulated by Q analogues in different ways depending on the hydrophobicity of their substituent. Membrane potential measurements have been undertaken to evaluate the energetic efficiency of complex I with various Q analogues. Only hydrophobic analogues such as nonyl-Q or undecyl-Q show an efficiency of membrane potential generation equivalent to that of endogenous Q. The less hydrophobic analogues as well as the isoprenoid analogue Q-2 are more efficient as substrates for the redox activity of complex I than for membrane potential generation. Thus the hydrophilic Q analogues act also as electron sinks and interact incompletely with the physiological Q site in complex I that pumps protons and generates membrane potential.

Accessory subunits of mitochondrial complex I

2013 ◽  
Vol 41 (5) ◽  
pp. 1272-1279 ◽  
Author(s):  
Katarzyna Kmita ◽  
Volker Zickermann
Keyword(s):  
Molecular Mass ◽  
Complex I ◽  
Proton Translocation ◽  
Present Review ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Cellular Functions ◽  
Accessory Subunits

Mitochondrial complex I has a molecular mass of almost 1 MDa and comprises more than 40 polypeptides. Fourteen central subunits harbour the bioenergetic core functions. We are only beginning to understand the significance of the numerous accessory subunits. The present review addresses the role of accessory subunits for assembly, stability and regulation of complex I and for cellular functions not directly associated with redox-linked proton translocation.

Escherichia coli NADH dehydrogenase I, a minimal form of the mitochondrial complex I

1993 ◽  
Vol 21 (4) ◽  
pp. 998-1001 ◽  
Author(s):  
Hans Leif ◽  
Uwe Weidner ◽  
Annette Berger ◽  
Volker Spehr ◽  
Matthias Braun ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Complex I ◽  
Nadh Dehydrogenase ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Minimal Form
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