Solvent control of oxidation state distribution and electronic delocalization in an osmium-ruthenium, mixed-metal dimer

Heme is an essential cofactor and signaling molecule. Heme acquisition by proteins and heme signaling are ultimately reliant on the ability to mobilize labile heme (LH). However, the properties of LH pools, including concentration, oxidation state, distribution, speciation, and dynamics, are poorly understood. Herein, we elucidate the nature and dynamics of LH using genetically encoded ratiometric fluorescent heme sensors in the unicellular eukaryoteSaccharomyces cerevisiae. We find that the subcellular distribution of LH is heterogeneous; the cytosol maintains LH at ∼20–40 nM, whereas the mitochondria and nucleus maintain it at concentrations below 2.5 nM. Further, we find that the signaling molecule nitric oxide can initiate the rapid mobilization of heme in the cytosol and nucleus from certain thiol-containing factors. We also find that the glycolytic enzyme glyceraldehyde phosphate dehydrogenase constitutes a major cellular heme buffer, and is responsible for maintaining the activity of the heme-dependent nuclear transcription factor heme activator protein (Hap1p). Altogether, we demonstrate that the heme sensors can be used to reveal fundamental aspects of heme trafficking and dynamics and can be used across multiple organisms, includingEscherichia coli, yeast, and human cell lines.

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Early High Oxidation State−Late Low Oxidation State Mixed-Metal Organometallics: Examples of Oxo-Bridged Tungsten−Ruthenium Acetylide Clusters

Organometallics ◽

10.1021/om960485t ◽

1997 ◽

Vol 16 (4) ◽

pp. 519-521 ◽

Cited By ~ 12

Author(s):

Peter Blenkiron ◽

Arthur J. Carty ◽

Shie-Ming Peng ◽

Gene-Hsiang Lee ◽

Chi-Jung Su ◽

...

Keyword(s):

Oxidation State ◽

High Oxidation State ◽

Mixed Metal ◽

High Oxidation ◽

Low Oxidation State

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Microwave-Assisted Synthesis of Mixed Metal-Oxide Nanoparticles

Journal of Nanoparticles ◽

10.1155/2013/737831 ◽

2013 ◽

Vol 2013 ◽

pp. 1-11 ◽

Cited By ~ 6

Author(s):

Akrati Verma ◽

Reena Dwivedi ◽

R. Prasad ◽

K. S. Bartwal

Keyword(s):

Oxidation State ◽

Combustion Method ◽

Mixed Metal Oxide ◽

Average Particle ◽

Particle Sizes ◽

Solution Combustion ◽

Solution Combustion Method ◽

Xps Spectra ◽

Mixed Metal ◽

Microwave Assisted

Nanoparticles of mixed metal oxides, ZrO2, ZrTiO4, and ZrV2O7 were prepared by microwave-assisted citrate sol-gel and solution combustion method. The prepared nanoparticles were characterized for their structural details using XRD and TEM techniques. The broadening of Raman bands is ascribed to local compositional fluctuations or local positional disordering produced due to random distribution of Zr4+ and Ti4+between equivalent sites. The XPS spectra confirm the incorporation of Ti in ZrO2 and suggest Zr as well as Ti in +4 oxidation state. Gelation and fast combustion seem to be the reason for smaller particle sizes. ZrV2O7 nanocrystalline material was synthesized by microwave- assisted solution combustion method. Low angle powder XRD measurements confirm the mesoporous nature of the prepared material. The effect of calcination temperature on the phase transformation of the materials has been investigated. Among tetragonal, monoclinic, and cubic phases, the monoclinic phase is predominant at higher calcinations temperature. The XPS confirms the incorporation of V2O5 in ZrO2 and suggests that Zr and V are in the same oxidation state (+4). The average particle sizes for ZrO2, ZrTiO4, and ZrV2O7 were found to be in the ranges of 5–10 nm, 2–5 nm, and 10–50 nm, respectively.

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