Simultaneous analyses of photoinduced electron transfer in the wild type and four single substitution isomers of the FMN binding protein from Desulfovibrio vulgaris, Miyazaki F

2011 ◽  
Vol 13 (13) ◽  
pp. 6085 ◽  
Author(s):  
Nadtanet Nunthaboot ◽  
Somsak Pianwanit ◽  
Sirirat Kokpol ◽  
Fumio Tanaka
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Binding Protein ◽  
Desulfovibrio Vulgaris ◽  
Wild Type ◽  
Substitution Isomers ◽  
In The Wild ◽  
Single Substitution

Photoinduced electron transfer in wild type and mutated flavodoxin from Desulfovibrio vulgaris, strain Miyazaki F.: Energy gap law

2011 ◽  
Vol 219 (1) ◽  
pp. 32-41 ◽  
Author(s):  
Kiattisak Lugsanangarm ◽  
Somsak Pianwanit ◽  
Sirirat Kokpol ◽  
Fumio Tanaka ◽  
Haik Chosrowjan ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Energy Gap ◽  
Desulfovibrio Vulgaris ◽  
Wild Type ◽  
Energy Gap Law

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.

scholarly journals Demonstration of Conformational Changes Associated with Activation of the Maltose Transport Complex

2001 ◽  
Vol 276 (15) ◽  
pp. 12362-12368 ◽  
Author(s):  
Daynene E. Mannering ◽  
Susan Sharma ◽  
Amy L. Davidson
Keyword(s):  
Conformational Changes ◽  
Atp Hydrolysis ◽  
Binding Protein ◽  
Nucleotide Binding ◽  
Wild Type ◽  
Nucleotide Binding Sites ◽  
Atp Binding Cassette Transporter ◽  
Aqueous Solvent ◽  
In The Wild ◽  
Transport Complex

InEscherichia coli, interaction of a periplasmic maltose-binding protein with a membrane-associated ATP-binding cassette transporter stimulates ATP hydrolysis, resulting in translocation of maltose into the cell. The maltose transporter contains two transmembrane subunits, MalF and MalG, and two copies of a nucleotide-hydrolyzing subunit, MalK. Mutant transport complexes that function in the absence of binding protein are thought to be stabilized in an ATPase-active conformation. To probe the conformation of the nucleotide-binding site and to gain an understanding of the nature of the conformational changes that lead to activation, cysteine 40 within the Walker A motif of the MalK subunit was modified by the fluorophore 2-(4′-maleimidoanilino)naphthalene-6-sulfonic acid. Fluorescence differences indicated that residues involved in nucleotide binding were less accessible to aqueous solvent in the binding protein independent transporter than in the wild-type transporter. Similar differences in fluorescence were seen when a vanadate-trapped transition state conformation was compared with the ground state in the wild-type transporter. Our results and recent crystal structures are consistent with a model in which activation of ATPase activity is associated with conformational changes that bring the two MalK subunits closer together, completing the nucleotide-binding sites and burying ATP in the interface.

scholarly journals Direct Observation of Electrically Conductive Pili Emanating from Geobacter sulfurreducens

2021 ◽  
Author(s):  
Xinying Liu ◽  
David Jeffrey Fraser Walker ◽  
Stephen Nonnenmann ◽  
Dezhi Sun ◽  
Derek R. Lovley
Keyword(s):  
Electron Transfer ◽  
Electron Transport ◽  
Long Range ◽  
Geobacter Sulfurreducens ◽  
Metal Corrosion ◽  
Extracellular Electron Transfer ◽  
Wild Type ◽  
Electrically Conductive ◽  
In The Wild ◽  
Pilin Gene

Geobacter sulfurreducens is a model microbe for elucidating the mechanisms for extracellular electron transfer in several biogeochemical cycles, bioelectrochemical applications, and microbial metal corrosion. Multiple lines of evidence previously suggested that electrically conductive pili (e-pili) are an essential conduit for long-range extracellular electron transport in G. sulfurreducens. However, it has recently been reported that G. sulfurreducens does not express e-pili and that filaments comprised of multi-heme c-type cytochromes are responsible for long-range electron transport. This possibility was directly investigated by examining cells, rather than filament preparations, with atomic force microscopy. Approximately 90 % of the filaments emanating from wild-type cells had a diameter (3 nm) and conductance consistent with previous reports of e-pili harvested from G. sulfurreducens or heterologously expressed in E. coli from the G. sulfurreducens pilin gene. The remaining 10% of filaments had a morphology consistent with filaments comprised of the c-type cytochrome OmcS. A strain expressing a modified pilin gene designed to yield poorly conductive pili expressed 90 % filaments with a 3 nm diameter, but greatly reduced conductance, further indicating that the 3 nm diameter conductive filaments in the wild-type strain were e-pili. A strain in which genes for five of the most abundant outer-surface c-type cytochromes, including OmcS, was deleted yielded only 3 nm diameter filaments with the same conductance as in the wild-type. These results demonstrate that e-pili are the most abundant conductive filaments expressed by G. sulfurreducens, consistent with previous functional studies demonstrating the need for e-pili for long-range extracellular electron transfer.

Lipids affect the charge stabilization in wild-type and mutant reaction centers of Rhodobacter sphaeroides R-26

1999 ◽  
Vol 26 (5) ◽  
pp. 465 ◽  
Author(s):  
László Nagy ◽  
Elfrida Fodor ◽  
Júlia Tandori ◽  
László Rinyu ◽  
Tibor Farkas
Keyword(s):  
Electron Transfer ◽  
Rhodobacter Sphaeroides ◽  
Electrostatic Interactions ◽  
Reaction Centers ◽  
Wild Type ◽  
Photosynthetic Membrane ◽  
Protein Ratio ◽  
Intracytoplasmic Membranes ◽  
In The Wild ◽  
Charge Stabilization

The effect of lipids on stabilization of electrons on the secondary quinone was studied in reaction centers (RC) of herbicide-sensitive and -resistant (L229Ile → Met) Rhodobacter sphaeroides R-26. The lipid concentration and the lipid/protein ratio of the intracytoplasmic membranes (ICM) were larger in the mutant RCs than in the wild-type. The free energy changes of Q A – Q B → Q A Q B – electron transfer were ΔG 0 = –57 meV, –69 meV, –85 meV for the wild-type and ΔG 0 = 0 meV, –15 meV, –46 meV for the mutant at pH = 8.0, in detergent, liposome and ICM, respectively. The differences in the stabilization energies of both strains decreased from the detergent via proteoliposome to chromatophore. We conclude that the energetics of the interquinone electron transfer depends on the environment of the reaction center. The steric and/or electrostatic interactions of the environment and Q B pocket can modulate the energetics of the charge stabilization over large distances. The interaction may have crucial importance on coupling the electron transport in the photosynthetic membrane to the anabolic/catabolic processes taking place in the cells.

scholarly journals Improper Localization of the OmcS Cytochrome May Explain the Inability of thexapD-Deficient Mutant ofGeobacter sulfurreducensto Reduce Fe(III) Oxide

2017 ◽  
Author(s):  
Kelly A. Flanagan ◽  
Ching Leang ◽  
Joy E. Ward ◽  
Derek R. Lovley
Keyword(s):  
Electron Transfer ◽  
Electron Transport ◽  
Type Strain ◽  
Wild Type Strain ◽  
Geobacter Sulfurreducens ◽  
Extracellular Electron Transfer ◽  
Outer Cell ◽  
Wild Type ◽  
Redox Active ◽  
In The Wild

AbstractExtracellular electron transfer through a redox-active exopolysaccharide matrix has been proposed as a strategy for extracellular electron transfer to Fe(III) oxide byGeobacter sulfurreducens,based on the phenotype of axapD-deficient strain. Central to this model was the assertion that thexapD-deficient strain produced pili decorated with the multi-hemec-type cytochrome OmcS in manner similar to the wild-type strain. Further examination of thexapD-deficient strain with immunogold labeling of OmcS and transmission electron microscopy revealed that OmcS was associated with the outer cell surface rather than pili. PilA, the pilus monomer, could not be detected in thexapD-deficient strain under conditions in which it was readily detected in the wild-type strain. Multiple lines of evidence in previous studies have suggested that long-range electron transport to Fe(III) oxides proceeds through electrically conductive pili and that OmcS associated with the pili is necessary for electron transfer from the pili to Fe(III) oxides. Therefore, an alternative explanation for the Fe(III) oxide reduction phenotype of thexapD-deficientstrain is that the pili-OmcS route for extracellular electron transport to Fe(III) oxide has been disrupted in thexapD-deficient strain.

scholarly journals Comparative Study on the Mechanism of Photoinduced Electron Transfer from Tryptophan 168 to Excited Flavin in T169S and Wild-type Pyranose 2-Oxidase

ACS Omega ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 593-605 ◽  
Author(s):  
Arthit Nueangaudom ◽  
Kiattisak Lugsanangarm ◽  
Somsak Pianwanit ◽  
Sirirat Kokpol ◽  
Nadtanet Nunthaboot ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Comparative Study ◽  
Photoinduced Electron Transfer ◽  
Wild Type
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