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Western University

Escherichia coli

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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Elastic Deformations Of The Rotary Double Motor Of Single F(O)F(1)-Atp Synthases Detected In Real Time By Förster Resonance Energy Transfer., Stefan Ernst, Monika G Düser, Nawid Zarrabi, Stanley D Dunn, Michael Börsch Oct 2012

Elastic Deformations Of The Rotary Double Motor Of Single F(O)F(1)-Atp Synthases Detected In Real Time By Förster Resonance Energy Transfer., Stefan Ernst, Monika G Düser, Nawid Zarrabi, Stanley D Dunn, Michael Börsch

Biochemistry Publications

Elastic conformational changes of the protein backbone are essential for catalytic activities of enzymes. To follow relative movements within the protein, Förster-type resonance energy transfer (FRET) between two specifically attached fluorophores can be applied. FRET provides a precise ruler between 3 and 8nm with subnanometer resolution. Corresponding submillisecond time resolution is sufficient to identify conformational changes in FRET time trajectories. Analyzing single enzymes circumvents the need for synchronization of various conformations. F(O)F(1)-ATP synthase is a rotary double motor which catalyzes the synthesis of adenosine triphosphate (ATP). A proton-driven 10-stepped rotary F(O) motor in the Escherichia coli enzyme is connected to …


Elastic Deformations Of The Rotary Double Motor Of Single F(O)F(1)-Atp Synthases Detected In Real Time By Förster Resonance Energy Transfer., Stefan Ernst, Monika G Düser, Nawid Zarrabi, Stanley D Dunn, Michael Börsch Oct 2012

Elastic Deformations Of The Rotary Double Motor Of Single F(O)F(1)-Atp Synthases Detected In Real Time By Förster Resonance Energy Transfer., Stefan Ernst, Monika G Düser, Nawid Zarrabi, Stanley D Dunn, Michael Börsch

Biochemistry Publications

Elastic conformational changes of the protein backbone are essential for catalytic activities of enzymes. To follow relative movements within the protein, Förster-type resonance energy transfer (FRET) between two specifically attached fluorophores can be applied. FRET provides a precise ruler between 3 and 8nm with subnanometer resolution. Corresponding submillisecond time resolution is sufficient to identify conformational changes in FRET time trajectories. Analyzing single enzymes circumvents the need for synchronization of various conformations. F(O)F(1)-ATP synthase is a rotary double motor which catalyzes the synthesis of adenosine triphosphate (ATP). A proton-driven 10-stepped rotary F(O) motor in the Escherichia coli enzyme is connected to …


Two Rotary Motors In F-Atp Synthase Are Elastically Coupled By A Flexible Rotor And A Stiff Stator Stalk., André Wächter, Yumin Bi, Stanley D Dunn, Brian D Cain, Hendrik Sielaff, Frank Wintermann, Siegfried Engelbrecht, Wolfgang Junge Mar 2011

Two Rotary Motors In F-Atp Synthase Are Elastically Coupled By A Flexible Rotor And A Stiff Stator Stalk., André Wächter, Yumin Bi, Stanley D Dunn, Brian D Cain, Hendrik Sielaff, Frank Wintermann, Siegfried Engelbrecht, Wolfgang Junge

Biochemistry Publications

ATP is synthesized by ATP synthase (F(O)F(1)-ATPase). Its rotary electromotor (F(O)) translocates protons (in some organisms sodium cations) and generates torque to drive the rotary chemical generator (F(1)). Elastic power transmission between F(O) and F(1) is essential for smoothing the cooperation of these stepping motors, thereby increasing their kinetic efficiency. A particularly compliant elastic domain is located on the central rotor (c(10-15)/ε/γ), right between the two sites of torque generation and consumption. The hinge on the active lever on subunit β adds further compliance. It is under contention whether or not the peripheral stalk (and the "stator" as a whole) …


The Proton-Translocating A Subunit Of F0f1-Atp Synthase Is Allocated Asymmetrically To The Peripheral Stalk., Monika G Düser, Yumin Bi, Nawid Zarrabi, Stanley D Dunn, Michael Börsch Nov 2008

The Proton-Translocating A Subunit Of F0f1-Atp Synthase Is Allocated Asymmetrically To The Peripheral Stalk., Monika G Düser, Yumin Bi, Nawid Zarrabi, Stanley D Dunn, Michael Börsch

Biochemistry Publications

The position of the a subunit of the membrane-integral F0 sector of Escherichia coli ATP synthase was investigated by single molecule fluorescence resonance energy transfer studies utilizing a fusion of enhanced green fluorescent protein to the C terminus of the a subunit and fluorescent labels attached to specific positions of the epsilon or gamma subunits. Three fluorescence resonance energy transfer levels were observed during rotation driven by ATP hydrolysis corresponding to the three resting positions of the rotor subunits, gamma or epsilon, relative to the a subunit of the stator. Comparison of these positions of the rotor sites with those …


Domain Compliance And Elastic Power Transmission In Rotary F(O)F(1)-Atpase., Hendrik Sielaff, Henning Rennekamp, André Wächter, Hao Xie, Florian Hilbers, Katrin Feldbauer, Stanley D Dunn, Siegfried Engelbrecht, Wolfgang Junge Nov 2008

Domain Compliance And Elastic Power Transmission In Rotary F(O)F(1)-Atpase., Hendrik Sielaff, Henning Rennekamp, André Wächter, Hao Xie, Florian Hilbers, Katrin Feldbauer, Stanley D Dunn, Siegfried Engelbrecht, Wolfgang Junge

Biochemistry Publications

The 2 nanomotors of rotary ATP synthase, ionmotive F(O) and chemically active F(1), are mechanically coupled by a central rotor and an eccentric bearing. Both motors rotate, with 3 steps in F(1) and 10-15 in F(O). Simulation by statistical mechanics has revealed that an elastic power transmission is required for a high rate of coupled turnover. Here, we investigate the distribution in the F(O)F(1) structure of compliant and stiff domains. The compliance of certain domains was restricted by engineered disulfide bridges between rotor and stator, and the torsional stiffness (kappa) of unrestricted domains was determined by analyzing their thermal rotary …


Probing The Functional Tolerance Of The B Subunit Of Escherichia Coli Atp Synthase For Sequence Manipulation Through A Chimera Approach., Yumin Bi, Joel C Watts, Pamela Krauss Bamford, Lee-Ann K Briere, Stanley D Dunn Jul 2008

Probing The Functional Tolerance Of The B Subunit Of Escherichia Coli Atp Synthase For Sequence Manipulation Through A Chimera Approach., Yumin Bi, Joel C Watts, Pamela Krauss Bamford, Lee-Ann K Briere, Stanley D Dunn

Biochemistry Publications

A dimer of 156-residue b subunits forms the peripheral stator stalk of eubacterial ATP synthase. Dimerization is mediated by a sequence with an unusual 11-residue (hendecad) repeat pattern, implying a right-handed coiled coil structure. We investigated the potential for producing functional chimeras in the b subunit of Escherichia coli ATP synthase by replacing parts of its sequence with corresponding regions of the b subunits from other eubacteria, sequences from other polypeptides having similar hendecad patterns, and sequences forming left-handed coiled coils. Replacement of positions 55-110 with corresponding sequences from Bacillus subtilis and Thermotoga maritima b subunits resulted in fully functional …


The Stator Complex Of The A1a0-Atp Synthase--Structural Characterization Of The E And H Subunits., Erik Kish-Trier, Lee-Ann K Briere, Stanley D Dunn, Stephan Wilkens Jan 2008

The Stator Complex Of The A1a0-Atp Synthase--Structural Characterization Of The E And H Subunits., Erik Kish-Trier, Lee-Ann K Briere, Stanley D Dunn, Stephan Wilkens

Biochemistry Publications

Archaeal ATP synthase (A-ATPase) is the functional homolog to the ATP synthase found in bacteria, mitochondria and chloroplasts, but the enzyme is structurally more related to the proton-pumping vacuolar ATPase found in the endomembrane system of eukaryotes. We have cloned, overexpressed and characterized the stator-forming subunits E and H of the A-ATPase from the thermoacidophilic Archaeon, Thermoplasma acidophilum. Size exclusion chromatography, CD, matrix-assisted laser desorption ionization time-of-flight mass spectrometry and NMR spectroscopic experiments indicate that both polypeptides have a tendency to form dimers and higher oligomers in solution. However, when expressed together or reconstituted, the two individual polypeptides interact with …