Transition metal transporters in rhizobia: tuning the inorganic micronutrient requirements to different living styles

Metallomics ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 735-755 ◽  
Author(s):  
Isidro Abreu ◽  
Paula Mihelj ◽  
Daniel Raimunda
Keyword(s):  
Transition Metal ◽  
Metal Transporters ◽  
Transition Metal Transporters

Transition metal transporters in rhizobia integrate the requirements of these micronutrients to the specific living styles.

scholarly journals Metal selectivity determinants in a family of transition metal transporters.

2018 ◽  
Vol 293 (1) ◽  
pp. 402-402
Author(s):  
Dorina Podar ◽  
Judith Scherer ◽  
Zeenat Noordally ◽  
Pawel Herzyk ◽  
Dietrich Nies ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Transporters ◽  
Metal Selectivity ◽  
Transition Metal Transporters

scholarly journals The role of transition metal transporters for iron, zinc, manganese, and copper in the pathogenesis of Yersinia pestis

Metallomics ◽  
2015 ◽  
Vol 7 (6) ◽  
pp. 965-978 ◽  
Author(s):  
Robert D. Perry ◽  
Alexander G. Bobrov ◽  
Jacqueline D. Fetherston
Keyword(s):  
Transition Metal ◽  
Yersinia Pestis ◽  
Causative Agent ◽  
Transport Systems ◽  
Metal Transporters ◽  
Pneumonic Plague ◽  
Transition Metal Transporters

Yersinia pestis, the causative agent of bubonic, septicemic and pneumonic plague, encodes a multitude of Fe transport systems.

scholarly journals Metal Selectivity Determinants in a Family of Transition Metal Transporters

2011 ◽  
Vol 287 (5) ◽  
pp. 3185-3196 ◽  
Author(s):  
Dorina Podar ◽  
Judith Scherer ◽  
Zeenat Noordally ◽  
Pawel Herzyk ◽  
Dietrich Nies ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Transporters ◽  
Metal Selectivity ◽  
Transition Metal Transporters

scholarly journals Conserved methionine dictates substrate preference in Nramp-family divalent metal transporters

2016 ◽  
Vol 113 (37) ◽  
pp. 10310-10315 ◽  
Author(s):  
Aaron T. Bozzi ◽  
Lukas B. Bane ◽  
Wilhelm A. Weihofen ◽  
Anne L. McCabe ◽  
Abhishek Singharoy ◽  
...  
Keyword(s):  
Amino Acid ◽  
Transition Metal ◽  
Transition Metals ◽  
Binding Site ◽  
Metal Binding ◽  
Toxic Metal ◽  
Natural Resistance ◽  
Metal Transporters ◽  
Metal Binding Site ◽  
Calcium And Magnesium

Natural resistance-associated macrophage protein (Nramp) family transporters catalyze uptake of essential divalent transition metals like iron and manganese. To discriminate against abundant competitors, the Nramp metal-binding site should favor softer transition metals, which interact either covalently or ionically with coordinating molecules, over hard calcium and magnesium, which interact mainly ionically. The metal-binding site contains an unusual, but conserved, methionine, and its sulfur coordinates transition metal substrates, suggesting a vital role in their transport. Using a bacterial Nramp model system, we show that, surprisingly, this conserved methionine is dispensable for transport of the physiological manganese substrate and similar divalents iron and cobalt, with several small amino acid replacements still enabling robust uptake. Moreover, the methionine sulfur’s presence makes the toxic metal cadmium a preferred substrate. However, a methionine-to-alanine substitution enables transport of calcium and magnesium. Thus, the putative evolutionary pressure to maintain the Nramp metal-binding methionine likely exists because it—more effectively than any other amino acid—increases selectivity for low-abundance transition metal transport in the presence of high-abundance divalents like calcium and magnesium.

HREM Study of electron-induced surface radiation damage in ReO3

1991 ◽  
Vol 49 ◽  
pp. 636-637
Author(s):  
R. Ai ◽  
H.-J. Fan ◽  
L. D. Marks
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Metal Oxides ◽  
Electron Irradiation ◽  
Transition Metal Oxides ◽  
Carbon Film ◽  
Transition Metal Ions ◽  
Surface Radiation ◽  
Valence Transition ◽  
Electron Microscopes

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.

Problems with oxygen analysis in the system MgO-Al2O3-SiO2 with the electron microprobe

1992 ◽  
Vol 50 (2) ◽  
pp. 1624-1625
Author(s):  
Michel Fialin ◽  
Guy Rémond
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Electrostatic Charge ◽  
Carbon Layer ◽  
Sample Holder ◽  
Rock Matrix ◽  
Electrical Discharges ◽  
Thin Carbon ◽  
Beam Instabilities

Oxygen-bearing minerals are generally strong insulators (e.g. silicates), or if not (e.g. transition metal oxides), they are included within a rock matrix which electrically isolates them from the sample holder contacts. In this respect, a thin carbon layer (150 Å in our laboratory) is evaporated on the sections in order to restore the conductivity. For silicates, overestimated oxygen concentrations are usually noted when transition metal oxides are used as standards. These trends corroborate the results of Bastin and Heijligers on MgO, Al2O3 and SiO2. According to our experiments, these errors are independent of the accelerating voltage used (fig.l).Owing to the low density of preexisting defects within the Al2O3 single-crystal, no significant charge buildup occurs under irradiation at low accelerating voltage (< 10keV). As a consequence, neither beam instabilities, due to electrical discharges within the excited volume, nor losses of energy for beam electrons before striking the sample, due to the presence of the electrostatic charge-induced potential, are noted : measurements from both coated and uncoated samples give comparable results which demonstrates that the carbon coating is not the cause of the observed errors.

Electron energy loss near edge structures of intermetallic alloys and grain boundaries in NiAl

1996 ◽  
Vol 54 ◽  
pp. 522-523
Author(s):  
G.A. Botton ◽  
C.J. Humphreys
Keyword(s):  
High Temperature ◽  
Transition Metal ◽  
Energy Loss ◽  
Grain Boundaries ◽  
Industrial Applications ◽  
Edge Structure ◽  
Structural Applications ◽  
Yield Behaviour ◽  
Late Transition ◽  
Metal Aluminides

Transition metal aluminides are of great potential interest for high temperature structural applications. Although these materials exhibit good mechanical properties at high temperature, their use in industrial applications is often limited by their intrinsic room temperature brittleness. Whilst this particular yield behaviour is directly related to the defect structure, the properties of the defects (in particular the mobility of dislocations and the slip system on which these dislocations move) are ultimately determined by the electronic structure and bonding in these materials. The lack of ductility has been attributed, at least in part, to the mixed bonding character (metallic and covalent) as inferred from ab-initio calculations. In this work, we analyse energy loss spectra and discuss the features of the near edge structure in terms of the relevant electronic states in order to compare the predictions on bonding directly with spectroscopic experiments. In this process, we compare spectra of late transition metal (TM) to early TM aluminides (FeAl and TiAl) to assess whether differences in bonding can also be detected. This information is then discussed in terms of bonding changes at grain boundaries in NiAl.

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