scholarly journals Selective biomineralization of Co3(PO4)2-sponges triggered by His-tagged proteins: efficient heterogeneous biocatalysts for redox processes

2015 ◽  
Vol 51 (42) ◽  
pp. 8753-8756 ◽  
Author(s):  
Fernando López-Gallego ◽  
Luis Yate
Keyword(s):  
Redox Processes ◽  
His Tag ◽  
Heterogeneous Biocatalysts ◽  
Cobalt Phosphate

Heterogeneous redox biocatalyts fabricated by mineralization of cobalt phosphate triggered by His-tag enzymes.

Anionic and Cationic Redox Processes in β-Li2IrO3 and Their Structural Implications on Electrochemical Cycling in Li-Ion Cell

2019 ◽  
Author(s):  
Paul Pearce ◽  
Gaurav Assat ◽  
Antonella Iadecola ◽  
François Fauth ◽  
Rémi Dedryvère ◽  
...  
Keyword(s):  
Analytical Techniques ◽  
Charge Compensation ◽  
Coupling Mechanism ◽  
Redox Processes ◽  
Positive Electrodes ◽  
X Ray ◽  
Electrochemical Cycling ◽  
Li Ion ◽  
Electrochemical Instability ◽  
High Degree

The recent discovery of anionic redox as a means to increase the energy density of transition metal oxide positive electrodes is now a well established approach in the Li-ion battery field. However, the science behind this new phenomenon pertaining to various Li-rich materials is still debated. Thus, it is of paramount importance to develop a robust set of analytical techniques to address this issue. Herein, we use a suite of synchrotron-based X-ray spectroscopies as well as diffraction techniques to thoroughly characterize the different redox processes taking place in a model Li-rich compound, the tridimentional hyperhoneycomb β-Li2IrO3. We clearly establish that the reversible removal of Li+ from this compound is associated to a previously described reductive coupling mechanism and the formation of the M-(O-O) and M-(O-O)* states. We further show that the respective contributions to these states determine the spectroscopic response for both Ir L3-edge X-ray absorption spectroscopy (XAS) and X-ray photoemissions spectroscopy (XPS). Although the high covalency and the robust tridimentional structure of this compound enable a high degree of reversibile delithiation, we found that pushing the limits of this charge compensation mechanism has significant effects on the local as well as average structure, leading to electrochemical instability over cycling and voltage decay. Overall, this work highlights the practical limits to which anionic redox can be exploited and sheds some light on the nature of the oxidized species formed in certain lithium-rich compounds.<br>

Anionic and Cationic Redox Processes in β-Li2IrO3 and Their Structural Implications on Electrochemical Cycling in Li-Ion Cell

2019 ◽  
Author(s):  
Paul Pearce ◽  
Gaurav Assat ◽  
Antonella Iadecola ◽  
François Fauth ◽  
Rémi Dedryvère ◽  
...  
Keyword(s):  
Analytical Techniques ◽  
Charge Compensation ◽  
Coupling Mechanism ◽  
Redox Processes ◽  
Positive Electrodes ◽  
X Ray ◽  
Electrochemical Cycling ◽  
Li Ion ◽  
Electrochemical Instability ◽  
High Degree

The recent discovery of anionic redox as a means to increase the energy density of transition metal oxide positive electrodes is now a well established approach in the Li-ion battery field. However, the science behind this new phenomenon pertaining to various Li-rich materials is still debated. Thus, it is of paramount importance to develop a robust set of analytical techniques to address this issue. Herein, we use a suite of synchrotron-based X-ray spectroscopies as well as diffraction techniques to thoroughly characterize the different redox processes taking place in a model Li-rich compound, the tridimentional hyperhoneycomb β-Li2IrO3. We clearly establish that the reversible removal of Li+ from this compound is associated to a previously described reductive coupling mechanism and the formation of the M-(O-O) and M-(O-O)* states. We further show that the respective contributions to these states determine the spectroscopic response for both Ir L3-edge X-ray absorption spectroscopy (XAS) and X-ray photoemissions spectroscopy (XPS). Although the high covalency and the robust tridimentional structure of this compound enable a high degree of reversibile delithiation, we found that pushing the limits of this charge compensation mechanism has significant effects on the local as well as average structure, leading to electrochemical instability over cycling and voltage decay. Overall, this work highlights the practical limits to which anionic redox can be exploited and sheds some light on the nature of the oxidized species formed in certain lithium-rich compounds.<br>

An Excel Workbook for Identifying Redox Processes in Ground Water

2009 ◽  
Author(s):  
Bryant C. Jurgens ◽  
Peter B. McMahon ◽  
Francis H. Chapelle ◽  
Sandra M. Eberts
Keyword(s):  
Ground Water ◽  
Redox Processes

Construction and Functional Analysis of the Recombinant Bacteriocins Weissellicin-MBF from Weissella confusa MBF8-1

2020 ◽  
Vol 22 (1) ◽  
pp. 115-122
Author(s):  
Amarila Malik ◽  
Elita Yuliantie ◽  
Nisa Yulianti Suprahman ◽  
Theresa Linardi ◽  
Angelina Wening Widiyanti ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Large Scale ◽  
Micrococcus Luteus ◽  
Affinity Column ◽  
Gene Expressions ◽  
His Tag ◽  
Recombinant Peptides ◽  
Weak Activity ◽  
Potential Alternative ◽  
Weissella Confusa

Background: Bacteriocins (Bac1, Bac2, and Bac3) from Weissella confusa MBF8-1, weissellicin- MBF, have been reported as potential alternative substances as well as complements to the existing antibiotics against many antimicrobial-resistant pathogens. Previously, the genes encoded in the large plasmid, pWcMBF8-1, and the spermicidal activity of their synthetic peptides, originally discovered Indonesia, have been studied. Three synthetic bacteriocins peptides of this weissellicin-MBF have been reported for their potential activities, i.e. antibacterial and spermicidal. Objective: The aim of this study was to construct the recombinant Bacteriocin (r-Bac) genes, as well as to investigate the gene expressions and their functional analysis. Method: Here, the recombinant Bacteriocin (r-Bac) genes were constructed and the recombinant peptides (r-Bac1, r-Bac2, and r-Bac3) in B. subtilis DB403 cells were produced on a large scale. After purification, using the His-tag affinity column, their potential bioactivities were measured as well as their antibacterial minimum inhibitory concentrations against Leuconostoc mesenteroides and Micrococcus luteus, were determined. Results: Pure His-tag-recombinant Bac1, Bac2, and Bac3 were obtained and they could inhibit the growth of L. mesenteroides and M. luteus. Conclusion: The recombinant bacteriocin could be obtained although with weak activity in inhibiting gram-positive bacterial growth.

scholarly journals Color-tuning of natural variants of heliorhodopsin

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Se-Hwan Kim ◽  
Kimleng Chuon ◽  
Shin-Gyu Cho ◽  
Ahreum Choi ◽  
Seanghun Meas ◽  
...  
Keyword(s):  
3D Structure ◽  
Site Directed Mutagenesis ◽  
Type I ◽  
Transmembrane Helices ◽  
Color Tuning ◽  
Tuning Mechanism ◽  
Spectral Changes ◽  
His Tag ◽  
Natural Variants ◽  
Retinal Chromophore

AbstractMicrobial rhodopsins are distributed through many microorganisms. Heliorhodopsins are newly discovered but have an unclear function. They have seven transmembrane helices similar to type-I and type-II rhodopsins, but they are different in that the N-terminal region of heliorhodopsin is cytoplasmic. We chose 13 representative heliorhodopsins from various microorganisms, expressed and purified with an N-terminal His tag, and measured the absorption spectra. The 13 natural variants had an absorption maximum (λmax) in the range 530–556 nm similar to proteorhodopsin (λmax = 490–525 nm). We selected several candidate residues that influence rhodopsin color-tuning based on sequence alignment and constructed mutants via site-directed mutagenesis to confirm the spectral changes. We found two important residues located near retinal chromophore that influence λmax. We also predict the 3D structure via homology-modeling of Thermoplasmatales heliorhodopsin. The results indicate that the color-tuning mechanism of type-I rhodopsin can be applied to understand the color-tuning of heliorhodopsin.

Driving forces for the adsorption of a His-tag Chagas antigen. A rational approach to design bio-functional surfaces

2013 ◽  
Vol 112 ◽  
pp. 294-301 ◽  
Author(s):  
Laura E. Valenti ◽  
Andrea M. Smania ◽  
Carlos P. De Pauli ◽  
Carla E. Giacomelli
Keyword(s):  
Driving Forces ◽  
Rational Approach ◽  
His Tag ◽  
Functional Surfaces ◽  
Antigen A
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