An Exposed Tyrosine on the Surface of Trimethylamine Dehydrogenase Facilitates Electron Transfer to Electron Transferring Flavoprotein:  Kinetics of Transfer in Wild-Type and Mutant Complexes†

Biochemistry ◽  
1997 ◽  
Vol 36 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Emma K. Wilson ◽  
Liuxin Huang ◽  
Michael J. Sutcliffe ◽  
F. Scott Mathews ◽  
Russ Hille ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Wild Type ◽  
Trimethylamine Dehydrogenase ◽  
Electron Transferring Flavoprotein ◽  
Kinetics Of

Flavin radicals, conformational sampling and robust design principles in interprotein electron transfer: the trimethylamine dehydrogenase-electron-transferring flavoprotein complex

2004 ◽  
Vol 71 ◽  
pp. 1-14
Author(s):  
David Leys ◽  
Jaswir Basran ◽  
François Talfournier ◽  
Kamaldeep K. Chohan ◽  
Andrew W. Munro ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Kinetic Studies ◽  
Molecular Assembly ◽  
Conformational Sampling ◽  
Trimethylamine Dehydrogenase ◽  
Key Residues ◽  
Electron Transferring Flavoprotein ◽  
Electron Transfer Complex

TMADH (trimethylamine dehydrogenase) is a complex iron-sulphur flavoprotein that forms a soluble electron-transfer complex with ETF (electron-transferring flavoprotein). The mechanism of electron transfer between TMADH and ETF has been studied using stopped-flow kinetic and mutagenesis methods, and more recently by X-ray crystallography. Potentiometric methods have also been used to identify key residues involved in the stabilization of the flavin radical semiquinone species in ETF. These studies have demonstrated a key role for 'conformational sampling' in the electron-transfer complex, facilitated by two-site contact of ETF with TMADH. Exploration of three-dimensional space in the complex allows the FAD of ETF to find conformations compatible with enhanced electronic coupling with the 4Fe-4S centre of TMADH. This mechanism of electron transfer provides for a more robust and accessible design principle for interprotein electron transfer compared with simpler models that invoke the collision of redox partners followed by electron transfer. The structure of the TMADH-ETF complex confirms the role of key residues in electron transfer and molecular assembly, originally suggested from detailed kinetic studies in wild-type and mutant complexes, and from molecular modelling.

scholarly journals Electron Transfer and Conformational Change in Complexes of Trimethylamine Dehydrogenase and Electron Transferring Flavoprotein

2001 ◽  
Vol 277 (10) ◽  
pp. 8457-8465 ◽  
Author(s):  
Matthew Jones ◽  
Francois Talfournier ◽  
Anton Bobrov ◽  
J. Günter Grossmann ◽  
Nikolai Vekshin ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Conformational Change ◽  
Trimethylamine Dehydrogenase ◽  
Electron Transferring Flavoprotein

scholarly journals Regulatory role of the respiratory supercomplex factors in Saccharomyces cerevisiae

2016 ◽  
Vol 113 (31) ◽  
pp. E4476-E4485 ◽  
Author(s):  
Camilla Rydström Lundin ◽  
Christoph von Ballmoos ◽  
Martin Ott ◽  
Pia Ädelroth ◽  
Peter Brzezinski
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Electron Transfer ◽  
Ligand Binding ◽  
Structural Changes ◽  
Regulatory Mechanism ◽  
Supramolecular Interactions ◽  
Wild Type ◽  
Single Turnover ◽  
Kinetics Of

The respiratory supercomplex factors (Rcf) 1 and 2 mediate supramolecular interactions between mitochondrial complexes III (ubiquinol-cytochrome c reductase; cyt. bc1) and IV (cytochrome c oxidase; CytcO). In addition, removal of these polypeptides results in decreased activity of CytcO, but not of cyt. bc1. In the present study, we have investigated the kinetics of ligand binding, the single-turnover reaction of CytcO with O2, and the linked cyt. bc1-CytcO quinol oxidation-oxygen-reduction activities in mitochondria in which Rcf1 or Rcf2 were removed genetically (strains rcf1Δ and rcf2Δ, respectively). The data show that in the rcf1Δ and rcf2Δ strains, in a significant fraction of the population, ligand binding occurs over a time scale that is ∼100-fold faster (τ ≅ 100 μs) than observed with the wild-type mitochondria (τ ≅ 10 ms), indicating structural changes. This effect is specific to removal of Rcf and not dissociation of the cyt. bc1–CytcO supercomplex. Furthermore, in the rcf1Δ and rcf2Δ strains, the single-turnover reaction of CytcO with O2 was incomplete. This observation indicates that the lower activity of CytcO is caused by a fraction of inactive CytcO rather than decreased CytcO activity of the entire population. Furthermore, the data suggest that the Rcf1 polypeptide mediates formation of an electron-transfer bridge from cyt. bc1 to CytcO via a tightly bound cyt. c. We discuss the significance of the proposed regulatory mechanism of Rcf1 and Rcf2 in the context of supramolecular interactions between cyt. bc1 and CytcO.

Electron Tunneling in Substrate-Reduced Trimethylamine Dehydrogenase: Kinetics of Electron Transfer and Analysis of the Tunneling Pathway

Biochemistry ◽  
1995 ◽  
Vol 34 (8) ◽  
pp. 2584-2591 ◽  
Author(s):  
Emma K. Wilson ◽  
F. S. Mathews ◽  
Leonard C. Packman ◽  
Nigel S. Scrutton
Keyword(s):  
Electron Transfer ◽  
Electron Tunneling ◽  
Trimethylamine Dehydrogenase ◽  
Kinetics Of

Kinetics of Electron Transfer between QA and QB in Wild Type and Herbicide-Resistant Mutants of Chlamydomonas reinhardtii

1993 ◽  
Vol 48 (3-4) ◽  
pp. 259-266 ◽  
Author(s):  
Antony R . Crofts ◽  
Irene Baroli ◽  
David Kramer ◽  
Shinichi Taoka
Keyword(s):  
Electron Transfer ◽  
Chlamydomonas Reinhardtii ◽  
Equilibrium Constants ◽  
Wild Type ◽  
Electron Transfer Kinetics ◽  
Herbicide Resistant ◽  
Mutant Strains ◽  
High Fluorescence ◽  
Kinetics Of ◽  
Separate Measurement

Abstract We have investigated the electron transfer kinetics for reduction of plastoquinone by photo­ system II in six mutant strains of Chlamydomonas reinhardtii by following the decay of the high fluorescence state after flash activation, and compared the separate reactions of the two-electron gate with those of a wild type strain. By analysis of the electron transfer kinetics, and separate measurement of the equilibrium constant for stabilization of the bound semiquinone after one flash, we have been able to deconvolute the contributions of rate constants and equilibrium constants for plastoquinone binding and electron transfer to the overall process. Two mutations, S 264 A and A 251 V, led to a marked slowing of kinetics for reduction of plastoquinone to the bound semiquinone. In S 264 A , the second electron transfer was also slower, but was normal in A 251 V. In mutant G 256 D , the electron transfer kinetics were normal after the first flash, but slowed after the second. In mutants L 257 F , V 219 I, and F 255 Y , the electron transfer kinetics after both flashes were similar to those in wild type. We discuss the results in terms of a model which provides a description of the mechanism of the two-electron gate in terms of measured kinetic and equilibrium constants, and we give values for these parameters in all strains tested.

Characterization and electron transfer kinetics of wild type and a mutant bf complex in Chlamydomonas reinhardtii

1996 ◽  
Vol 24 (3) ◽  
pp. 398S-398S ◽  
Author(s):  
MÓNICA ONDÁRROA ◽  
FRANCESCA ZITO ◽  
GIOVANNI FINAZZI ◽  
PIERRE JOLIOT ◽  
FRANCIS-ANDRÈ WOLLMAN ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Chlamydomonas Reinhardtii ◽  
Wild Type ◽  
Electron Transfer Kinetics ◽  
Kinetics Of
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