Time-resolved IR spectroscopy reveals mechanistic details of ion transport in the sodium pump Krokinobacter eikastus rhodopsin 2

2019 ◽  
Vol 21 (8) ◽  
pp. 4461-4471 ◽  
Author(s):  
Marvin Asido ◽  
Peter Eberhardt ◽  
Clara Nassrin Kriebel ◽  
Markus Braun ◽  
Clemens Glaubitz ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Comparative Study ◽  
Ion Transport ◽  
Structural Dynamics ◽  
Sodium Pump ◽  
Proton Pumping ◽  
Wild Type ◽  
Time Resolved

We report a comparative study on the structural dynamics of the light-driven sodium pump Krokinobacter eikastus rhodopsin 2 wild type under sodium and proton pumping conditions by means of time-resolved IR spectroscopy.

A Comparative Study of Tricarbonylmanganese Photoactivatable CO Releasing Molecules (PhotoCORMs) by Using the Myoglobin Assay and Time-Resolved IR Spectroscopy

2012 ◽  
Vol 2012 (19) ◽  
pp. 3140-3146 ◽  
Author(s):  
Wilhelm Huber ◽  
Rolf Linder ◽  
Johanna Niesel ◽  
Ulrich Schatzschneider ◽  
Bernhard Spingler ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Comparative Study ◽  
Time Resolved

scholarly journals Protein Structural Dynamics of Wild-Type and Mutant Homodimeric Hemoglobin Studied by Time-Resolved X-Ray Solution Scattering

2018 ◽  
Vol 19 (11) ◽  
pp. 3633 ◽  
Author(s):  
Cheolhee Yang ◽  
Minseo Choi ◽  
Jong Kim ◽  
Hanui Kim ◽  
Srinivasan Muniyappan ◽  
...  
Keyword(s):  
Structural Dynamics ◽  
Conformational Changes ◽  
Structural Transition ◽  
Quaternary Structure ◽  
Heme Binding ◽  
Wild Type ◽  
Time Resolved ◽  
X Ray ◽  
Protein Structural Dynamics ◽  
Cooperative Transition

The quaternary transition between the relaxed (R) and tense (T) states of heme-binding proteins is a textbook example for the allosteric structural transition. Homodimeric hemoglobin (HbI) from Scapharca inaequivalvis is a useful model system for investigating the allosteric behavior because of the relatively simple quaternary structure. To understand the cooperative transition of HbI, wild-type and mutants of HbI have been studied by using time-resolved X-ray solution scattering (TRXSS), which is sensitive to the conformational changes. Herein, we review the structural dynamics of HbI investigated by TRXSS and compare the results of TRXSS with those of other techniques.

scholarly journals Transmembrane Charge Separation during the Ferryl-oxo → Oxidized Transition in a Nonpumping Mutant of CytochromecOxidase

2004 ◽  
Vol 279 (50) ◽  
pp. 52558-52565 ◽  
Author(s):  
Sergey A. Siletsky ◽  
Ashtamurthy S. Pawate ◽  
Kara Weiss ◽  
Robert B. Gennis ◽  
Alexander A. Konstantinov
Keyword(s):  
Electron Transfer ◽  
Aqueous Phase ◽  
Proton Translocation ◽  
Proton Pumping ◽  
K Channel ◽  
Wild Type ◽  
Time Resolved ◽  
In The Wild ◽  
Solvent Isotope ◽  
Charge Translocation

The N139D mutant of cytochromecoxidase fromRhodobacter sphaeroidesretains full steady state oxidase activity but completely lacks proton translocation coupled to turnover in reconstituted liposomes (Pawate, A. S., Morgan, J., Namslauer, A., Mills, D., Brzezinski, P., Ferguson-Miller, S., and Gennis, R. B. (2002)Biochemistry41, 13417–13423). Here, time-resolved electron transfer and vectorial charge translocation in the ferryl-oxo → oxidized transition (transfer of the 4th electron in the catalytic cycle) have been studied with the N139D mutant using ruthenium(II)-tris-bipyridyl complex as a photoactive single-electron donor. With the wild type oxidase, the flash-induced generation of Δφ in the ferryl-oxo → oxidized transition begins with rapid vectorial electron transfer from CuAto heme a (τ ∼15 μs), followed by two protonic phases, referred to as the intermediate (0.4 ms) and slow electrogenic phases (1.5 ms). In the N139D mutant, only a single protonic phase (τ ∼0.6 ms) is observed, which was associated with electron transfer from heme a to the heme a3/CuBsite and decelerates ∼4-fold in D2O. With the wild type oxidase, such a high H2O/D2O solvent isotope effect is characteristic of only the slow (1.5 ms) phase. Presumably, the 0.6-ms electrogenic phase in the N139D mutant reports proton transfer from the inner aqueous phase to Glu-286, replacing the “chemical” proton transferred from Glu-286 to the heme a3/CuBsite. The transfer occurs through the D-channel, because it is observed also in the N139D/K362M double mutant in which the K-channel is blocked. It is concluded that the intermediate electrogenic phase observed in the wild type enzyme is missing in the N139D mutant and is because of translocation of the “pumped” proton from Glu-286 to the D-ring propionate of heme a3or to release of this proton to the outer aqueous phase. Significantly, with the wild type oxidase, the protonic electrogenic phase associated with proton pumping (∼0.4 ms) precedes the electrogenic phase associated with the oxygen chemistry (∼1.5 ms).

Structural dynamics of P-type ATPase ion pumps

2019 ◽  
Vol 47 (5) ◽  
pp. 1247-1257 ◽  
Author(s):  
Mateusz Dyla ◽  
Sara Basse Hansen ◽  
Poul Nissen ◽  
Magnus Kjaergaard
Keyword(s):  
Structural Dynamics ◽  
Single Molecule ◽  
New Technologies ◽  
Atp Hydrolysis ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Time Resolved ◽  
Dynamics Simulations ◽  
Types Of Information ◽  
P Type

Abstract P-type ATPases transport ions across biological membranes against concentration gradients and are essential for all cells. They use the energy from ATP hydrolysis to propel large intramolecular movements, which drive vectorial transport of ions. Tight coordination of the motions of the pump is required to couple the two spatially distant processes of ion binding and ATP hydrolysis. Here, we review our current understanding of the structural dynamics of P-type ATPases, focusing primarily on Ca2+ pumps. We integrate different types of information that report on structural dynamics, primarily time-resolved fluorescence experiments including single-molecule Förster resonance energy transfer and molecular dynamics simulations, and interpret them in the framework provided by the numerous crystal structures of sarco/endoplasmic reticulum Ca2+-ATPase. We discuss the challenges in characterizing the dynamics of membrane pumps, and the likely impact of new technologies on the field.

Surface chemistry of H-ZSM5 studied by time-resolved IR spectroscopy

1989 ◽  
Vol 51 (3) ◽  
pp. 309-327 ◽  
Author(s):  
Andreas Jentys ◽  
Gerhard Warecka ◽  
Johannes A. Lercher
Keyword(s):  
Ir Spectroscopy ◽  
Surface Chemistry ◽  
Time Resolved

scholarly journals Mutation of a single residue in the ba3 oxidase specifically impairs protonation of the pump site

2015 ◽  
Vol 112 (11) ◽  
pp. 3397-3402 ◽  
Author(s):  
Christoph von Ballmoos ◽  
Nathalie Gonska ◽  
Peter Lachmann ◽  
Robert B. Gennis ◽  
Pia Ädelroth ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Time Constant ◽  
Thermus Thermophilus ◽  
Proton Translocation ◽  
Proton Pumping ◽  
Wild Type ◽  
Structural Variant ◽  
In The Wild ◽  
Membrane Bound ◽  
Proton Uptake

The ba3-type cytochrome c oxidase from Thermus thermophilus is a membrane-bound protein complex that couples electron transfer to O2 to proton translocation across the membrane. To elucidate the mechanism of the redox-driven proton pumping, we investigated the kinetics of electron and proton transfer in a structural variant of the ba3 oxidase where a putative “pump site” was modified by replacement of Asp372 by Ile. In this structural variant, proton pumping was uncoupled from internal electron transfer and O2 reduction. The results from our studies show that proton uptake to the pump site (time constant ∼65 μs in the wild-type cytochrome c oxidase) was impaired in the Asp372Ile variant. Furthermore, a reaction step that in the wild-type cytochrome c oxidase is linked to simultaneous proton uptake and release with a time constant of ∼1.2 ms was slowed to ∼8.4 ms, and in Asp372Ile was only associated with proton uptake to the catalytic site. These data identify reaction steps that are associated with protonation and deprotonation of the pump site, and point to the area around Asp372 as the location of this site in the ba3 cytochrome c oxidase.

Pharmacological modulation of ion transport across wild-type and ΔF508 CFTR-expressing human bronchial epithelia

2000 ◽  
Vol 279 (2) ◽  
pp. C461-C479 ◽  
Author(s):  
Daniel C. Devor ◽  
Robert J. Bridges ◽  
Joseph M. Pilewski
Keyword(s):  
Cystic Fibrosis ◽  
Ion Transport ◽  
Short Circuit ◽  
Primary Cultures ◽  
Short Circuit Current ◽  
Bronchial Epithelium ◽  
Disulfonic Acid ◽  
Wild Type ◽  
Pharmacological Agents ◽  
Transport Defect

Forskolin, UTP, 1-ethyl-2-benzimidazolinone (1-EBIO), NS004, 8-methoxypsoralen (Methoxsalen; 8-MOP), and genistein were evaluated for their effects on ion transport across primary cultures of human bronchial epithelium (HBE) expressing wild-type (wt HBE) and ΔF508 (ΔF-HBE) cystic fibrosis transmembrane conductance regulator. In wt HBE, the baseline short-circuit current ( I sc) averaged 27.0 ± 0.6 μA/cm2 ( n = 350). Amiloride reduced this I sc by 13.5 ± 0.5 μA/cm2 ( n = 317). In ΔF-HBE, baseline I sc was 33.8 ± 1.2 μA/cm2 ( n = 200), and amiloride reduced this by 29.6 ± 1.5 μA/cm2 ( n = 116), demonstrating the characteristic hyperabsorption of Na+ associated with cystic fibrosis (CF). In wt HBE, subsequent to amiloride, forskolin induced a sustained, bumetanide-sensitive I sc(Δ I sc = 8.4 ± 0.8 μA/cm2; n = 119). Addition of acetazolamide, 5-( N-ethyl- N-isopropyl)-amiloride, and serosal 4,4′-dinitrostilben-2,2′-disulfonic acid further reduced I sc, suggesting forskolin also stimulates HCO3 − secretion. This was confirmed by ion substitution studies. The forskolin-induced I scwas inhibited by 293B, Ba2+, clofilium, and quinine, whereas charybdotoxin was without effect. In ΔF-HBE the forskolin I sc response was reduced to 1.2 ± 0.3 μA/cm2 ( n = 30). In wt HBE, mucosal UTP induced a transient increase in I sc (Δ I sc = 15.5 ± 1.1 μA/cm2; n = 44) followed by a sustained plateau, whereas in ΔF-HBE the increase in I sc was reduced to 5.8 ± 0.7 μA/cm2 ( n = 13). In wt HBE, 1-EBIO, NS004, 8-MOP, and genistein increased I sc by 11.6 ± 0.9 ( n = 20), 10.8 ± 1.7 ( n = 18), 10.0 ± 1.6 ( n = 5), and 7.9 ± 0.8 μA/cm2( n = 17), respectively. In ΔF-HBE, 1-EBIO, NS004, and 8-MOP failed to stimulate Cl− secretion. However, addition of NS004 subsequent to forskolin induced a sustained Cl−secretory response (2.1 ± 0.3 μA/cm2, n = 21). In ΔF-HBE, genistein alone stimulated Cl− secretion (2.5 ± 0.5 μA/cm2, n = 11). After incubation of ΔF-HBE at 26°C for 24 h, the responses to 1-EBIO, NS004, and genistein were all potentiated. 1-EBIO and genistein increased Na+ absorption across ΔF-HBE, whereas NS004 and 8-MOP had no effect. Finally, Ca2+-, but not cAMP-mediated agonists, stimulated K+ secretion across both wt HBE and ΔF-HBE in a glibenclamide-dependent fashion. Our results demonstrate that pharmacological agents directed at both basolateral K+ and apical Cl− conductances directly modulate Cl−secretion across HBE, indicating they may be useful in ameliorating the ion transport defect associated with CF.

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