scholarly journals Structural and functional properties of a magnesium transporter of the SLC11/NRAMP family

eLife ◽  
2022 ◽  
Vol 11 ◽  
Author(s):  
Karthik Ramanadane ◽  
Monique S Straub ◽  
Raimund Dutzler ◽  
Cristina Manatschal
Keyword(s):  
Hydration Shell ◽  
Transition Metal Ions ◽  
Ion Binding ◽  
X Ray ◽  
X Ray Crystallography ◽  
Protein Architecture ◽  
Large Pool ◽  
Structural And Functional Properties ◽  
The Family ◽  
Magnesium Transporter

Members of the ubiquitous SLC11/NRAMP family catalyze the uptake of divalent transition metal ions into cells. They have evolved to efficiently select these trace elements from a large pool of Ca2+ and Mg2+, which are both orders of magnitude more abundant, and to concentrate them in the cytoplasm aided by the cotransport of H+ serving as energy source. In the present study, we have characterized a member of a distant clade of the family found in prokaryotes, termed NRMTs, that were proposed to function as transporters of Mg2+. The protein transports Mg2+ and Mn2+ but not Ca2+ by a mechanism that is not coupled to H+. Structures determined by cryo-EM and X-ray crystallography revealed a generally similar protein architecture compared to classical NRAMPs, with a restructured ion binding site whose increased volume provides suitable interactions with ions that likely have retained much of their hydration shell.

scholarly journals Structural and functional properties of a magnesium transporter of the SLC11/NRAMP family

2021 ◽  
Author(s):  
Karthik Ramanadane ◽  
Monique S Straub ◽  
Raimund Dutzler ◽  
Cristina Manatschal
Keyword(s):  
Hydration Shell ◽  
Transition Metal Ions ◽  
Ion Binding ◽  
X Ray ◽  
X Ray Crystallography ◽  
Protein Architecture ◽  
Large Pool ◽  
Structural And Functional Properties ◽  
The Family ◽  
Magnesium Transporter

Members of the ubiquitous SLC11/NRAMP family catalyze the uptake of divalent transition metal ions into cells. They have evolved to efficiently select these trace elements from a large pool of Ca2+ and Mg2+, which are both orders of magnitude more abundant, and to concentrate them in the cytoplasm aided by the cotransport of H+ serving as energy source. In the present study, we have characterized a member of a distant clade of the family found in prokaryotes, termed NRMTs, that were proposed to function as transporters of Mg2+. The protein transports Mg2+ and Mn2+ but not Ca2+ by a mechanism that is not coupled to H+. Structures determined by cryo-EM and X-ray crystallography revealed a generally similar protein architecture compared to classical NRAMPs, with a restructured ion binding site whose increased volume provides suitable interactions with ions that likely have retained much of their hydration shell.

scholarly journals Molecular mechanism of ATP versus GTP selectivity of adenylate kinase

2018 ◽  
Vol 115 (12) ◽  
pp. 3012-3017 ◽  
Author(s):  
Per Rogne ◽  
Marie Rosselin ◽  
Christin Grundström ◽  
Christian Hedberg ◽  
Uwe H. Sauer ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Adenylate Kinase ◽  
Function Analysis ◽  
Substrate Selectivity ◽  
Cellular Functions ◽  
X Ray ◽  
Precise Control ◽  
X Ray Crystallography ◽  
The Family ◽  
Atp Analogs

Enzymatic substrate selectivity is critical for the precise control of metabolic pathways. In cases where chemically related substrates are present inside cells, robust mechanisms of substrate selectivity are required. Here, we report the mechanism utilized for catalytic ATP versus GTP selectivity during adenylate kinase (Adk) -mediated phosphorylation of AMP. Using NMR spectroscopy we found that while Adk adopts a catalytically competent and closed structural state in complex with ATP, the enzyme is arrested in a catalytically inhibited and open state in complex with GTP. X-ray crystallography experiments revealed that the interaction interfaces supporting ATP and GTP recognition, in part, are mediated by coinciding residues. The mechanism provides an atomic view on how the cellular GTP pool is protected from Adk turnover, which is important because GTP has many specialized cellular functions. In further support of this mechanism, a structure–function analysis enabled by synthesis of ATP analogs suggests that a hydrogen bond between the adenine moiety and the backbone of the enzyme is vital for ATP selectivity. The importance of the hydrogen bond for substrate selectivity is likely general given the conservation of its location and orientation across the family of eukaryotic protein kinases.

scholarly journals Chiral C2-Symmetric Diimines with 4,5-Diazafluorene Units

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3186 ◽  
Author(s):  
Vasilyev ◽  
Bizyaev ◽  
Komarov ◽  
Gatilov ◽  
Tkachev
Keyword(s):  
Calculated Data ◽  
Transition Metal Ions ◽  
Synthetic Approach ◽  
Spectroscopic Methods ◽  
Aromatic Diamines ◽  
X Ray ◽  
X Ray Crystallography ◽  
Chemical Structures ◽  
Polydentate Ligands ◽  
New Compounds

A synthetic approach to a new group of stable chiral C2-symmetric diimines with the 4,5-diazafluorene core has been developed based on condensation of dipinodiazafluorene with aromatic diamines. The chemical structures of new compounds were proven by spectroscopic methods and X-ray crystallography. All the compounds form solvates with organic solvents (chloroform, benzene, 1,4-dioxane) and water. Specific spectral data of the new compounds are explained using calculated data (DFT). Diimines of the pinodiazafluorene series give colored reactions with transition metal ions and can be regarded as prospective polydentate ligands with interesting luminescent and chiroptical properties.

Influence of metal ions on the formation of new metal complexes constructed from tetrachlorophthalic acid

2015 ◽  
Vol 70 (10) ◽  
pp. 711-718
Author(s):  
An-Qi Dai ◽  
Qi Yan ◽  
Jing Zhong ◽  
Sheng-Chun Chen ◽  
Ming-Yang He ◽  
...  
Keyword(s):  
Metal Ions ◽  
Significant Contribution ◽  
Transition Metal Ions ◽  
Planar Geometry ◽  
X Ray ◽  
X Ray Crystallography ◽  
Transitional Metal ◽  
Square Planar ◽  
Structural Differences ◽  
Metal Effect

AbstractReaction of 3,4,5,6-tetrachloro-1,2-benzenedicarboxylyic acid (1,2-H2BDC-Cl4) with transitional metal salts at room temperature in mixed DMF/H2O solvent affords three complexes formulated as [Cu(1,2-HBDC-Cl4)2(DMF)2] (1), {[Cd(1,2-HBDC-Cl4)2(H2O)4]·2DMF} (2), and {[Ni(1,2-BDC-Cl4)(H2O)5]·DMF·H2O} (3) (DMF = N,N-dimethylformamide). All these complexes have been characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and single-crystal X-ray crystallography. In 1, the CuII ion is four-coordinated with a square-planar geometry formed by two 1,2-HBDC-Cl4 anions and two DMF ligands; in 2, the CdII ion takes an octahedral geometry coordinated by two 1,2-HBDC-Cl4 anions and four aqua ligands; while in 3, the NiII ion is octahedrally coordinated by one 1,2-BDC-Cl4 dianion and five aqua ligands. Intermolecular O–H···O hydrogen bonds and Cl···Cl (or C–H···Cl) interactions provide a significant contribution to stabilizing the three mononuclear structures in the solid state. The results suggest that structural differences among them are attributed to the influence of transition metal ions. The fluorescence of the complexes and of 1,2-H2BDC-Cl4 has been investigated. No significant metal effect has been observed.

scholarly journals Expanding the Family of Tetrahalide Iron Complexes: Synthesis, Structure and Biological Applications.

2020 ◽  
Author(s):  
Nusrat Abedin ◽  
Abdullah Hamed A Alshehri ◽  
Ali M A Almughrbi ◽  
Olivia Moore ◽  
Sheikh Alyza ◽  
...  
Keyword(s):  
Antimicrobial Properties ◽  
Biological Properties ◽  
Biological Applications ◽  
X Ray ◽  
Mononuclear Iron ◽  
X Ray Crystallography ◽  
Gram Positive Bacteria ◽  
Axial Ligands ◽  
The Family ◽  
Resistant Strains

A neutral octahedral mononuclear iron(II) tetrabromide complex, [Fe(Hampy)<sub>2</sub>Br<sub>4</sub>], that consists of equatorial bromide and protonated aminopyrazinium axial ligands is successfully synthesised through redox chemistry and analysed using X-ray crystallography. The iron(II) oxidation state is balanced by the protonated pyrazinium nitrogen just outside the coordination sphere. The biological properties of this and two other related complexes are investigated using both Gram-negative and Gram-positive bacteria as well as methicillin resistant strains. They all exhibit some antimicrobial properties albeit at moderate to poor concentrations. However, the tetrahalide complexes analysed exhibit excellent anti biofilm properties well below cytotoxic levels.

scholarly journals Structure and transport mechanism of the sodium/proton antiporter MjNhaP1

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Cristina Paulino ◽  
David Wöhlert ◽  
Ekaterina Kapotova ◽  
Özkan Yildiz ◽  
Werner Kühlbrandt
Keyword(s):  
Transport Mechanism ◽  
Ion Binding ◽  
Ph Homeostasis ◽  
Activity Maximum ◽  
X Ray ◽  
X Ray Crystallography ◽  
Highly Active ◽  
Health And Disease ◽  
Cooperative Transport ◽  
22Na Uptake

Sodium/proton antiporters are essential for sodium and pH homeostasis and play a major role in human health and disease. We determined the structures of the archaeal sodium/proton antiporter MjNhaP1 in two complementary states. The inward-open state was obtained by x-ray crystallography in the presence of sodium at pH 8, where the transporter is highly active. The outward-open state was obtained by electron crystallography without sodium at pH 4, where MjNhaP1 is inactive. Comparison of both structures reveals a 7° tilt of the 6 helix bundle. 22Na+ uptake measurements indicate non-cooperative transport with an activity maximum at pH 7.5. We conclude that binding of a Na+ ion from the outside induces helix movements that close the extracellular cavity, open the cytoplasmic funnel, and result in a ∼5 Å vertical relocation of the ion binding site to release the substrate ion into the cytoplasm.

scholarly journals Expanding the Family of Tetrahalide Iron Complexes: Synthesis, Structure and Biological Applications.

2020 ◽  
Author(s):  
Nusrat Abedin ◽  
Abdullah Hamed A Alshehri ◽  
Ali M A Almughrbi ◽  
Olivia Moore ◽  
Sheikh Alyza ◽  
...  
Keyword(s):  
Antimicrobial Properties ◽  
Biological Properties ◽  
Biological Applications ◽  
X Ray ◽  
Mononuclear Iron ◽  
X Ray Crystallography ◽  
Gram Positive Bacteria ◽  
Axial Ligands ◽  
The Family ◽  
Resistant Strains

A neutral octahedral mononuclear iron(II) tetrabromide complex, [Fe(Hampy)<sub>2</sub>Br<sub>4</sub>], that consists of equatorial bromide and protonated aminopyrazinium axial ligands is successfully synthesised through redox chemistry and analysed using X-ray crystallography. The iron(II) oxidation state is balanced by the protonated pyrazinium nitrogen just outside the coordination sphere. The biological properties of this and two other related complexes are investigated using both Gram-negative and Gram-positive bacteria as well as methicillin resistant strains. They all exhibit some antimicrobial properties albeit at moderate to poor concentrations. However, the tetrahalide complexes analysed exhibit excellent anti biofilm properties well below cytotoxic levels.

Crystal-Structure of Bis(2,2'-6',2'-terpyridine)manganese(II) Bis(triiodide) [Mn(terpy)2](I3)2

1991 ◽  
Vol 44 (2) ◽  
pp. 303 ◽  
Author(s):  
R Bhula ◽  
DC Weatherburn
Keyword(s):  
Crystal Structure ◽  
Transition Metal ◽  
Metal Ions ◽  
Coordination Sphere ◽  
Metal Ion ◽  
Transition Metal Ions ◽  
Triclinic Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
Distorted Octahedral

The crystal structure of [ Mn ( terpy )2](I3)2( terpy = 2,2°:6°,2°-terpyridene) has been determined by X-ray crystallography. The crystals are triclinic, space group Pī , a 9.357(4), b 8.600(2), c 24.531(8) Ǻ, α 93.64(2), B 95.58(3), γ 91.52(2)°, Z 2, V 1960(1)Ǻ3. The structure has been refined to a residual R of 0.065 (Rw 0.070). The coordination sphere of the metal ion is distorted octahedral with each terpy ligand coordinated in a meridional fashion. The structure is compared with those of other M( terpy )2n+ complexes formed by first-row transition metal ions.

Syntheses, crystal structures and phosphorescence properties of cyclometalated iridium(III) bis(pyridylbenzaldehyde) complexes with dithiolate ligands

2017 ◽  
Vol 72 (12) ◽  
pp. 941-946 ◽  
Author(s):  
Xue-Mei Wang ◽  
Jia-Yan Qiang ◽  
Ai-Quan Jia ◽  
Bihai Tong ◽  
Qian-Feng Zhang
Keyword(s):  
Crystal Structures ◽  
Emission Spectra ◽  
Transition Metal Ions ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Water Solvent ◽  
The Stability ◽  
C Nmr ◽  
Composition Of Complexes

AbstractThe synthesis of three neutral bis-cyclometalated iridium(III) complexes [Ir(pba)2(S^S)] (pbaH=4-(2-pyridyl)benzaldehyde; S^S=Et2NCS2− (1), iPrOCS2− (2), (nPrO)2PS2− (3)) from [{Ir(μ-Cl)(pba)2}2] and the corresponding sodium or potassium dithiolates in methanol-dichloromethane is described. The composition of complexes 1–3 is discussed on the basis of 1H NMR, 13C NMR, IR, and mass spectroscopy, and the crystal structures of 1 and 3 were determined by X-ray crystallography. The absorption and emission spectra show that the [Ir(pba)2(S^S)] complexes may be effective candidates as green-emitting phosphorescent materials. The stability of the three cyclometalated iridium(III) complexes towards different transition metal ions was also investigated in acetonitrile-water solvent.

scholarly journals Divalent cation and chloride ion sites of chicken acid sensing ion channel 1a elucidated by x-ray crystallography

2018 ◽  
Author(s):  
Nate Yoder ◽  
Eric Gouaux
Keyword(s):  
Ion Channels ◽  
Divalent Cation ◽  
Binding Sites ◽  
Divalent Cations ◽  
Cation Binding ◽  
Ion Binding ◽  
X Ray ◽  
High Ph ◽  
X Ray Crystallography ◽  
Ion Binding Sites

AbstractAcid sensing ion channels (ASICs) are proton-gated ion channels that are members of the degenerin/epithelial sodium channel superfamily and are expressed throughout central and peripheral nervous systems. ASICs have been implicated in multiple physiological processes and are subject to numerous forms of endogenous and exogenous regulation that include modulation by Ca2+ and Cl− ions. However, the mapping of ion binding sites as well as a structure-based understanding of the mechanisms underlying ionic modulation of ASICs have remained elusive. Here we present ion binding sites of chicken ASIC1a in resting and desensitized states at high and low pH, respectively, determined by anomalous diffraction x-ray crystallography. The acidic pocket serves as a nexus for divalent cation binding at both low and high pH, while we observe divalent cation binding within the central vestibule on the resting channel at high pH only. Moreover, neutralization of residues positioned to coordinate divalent cations via individual and combined Glu to Gln substitutions reduced, but did not extinguish, modulation of proton-dependent gating by Ca2+. Additionally, we demonstrate that anion binding at the canonical thumb domain site is state-dependent and present a previously undetected anion site at the mouth of the extracellular fenestrations on the resting channel. Our results map anion and cation sites on ASICs across multiple functional states, informing possible mechanisms of modulation and providing a blueprint for the design of therapeutics targeting ASICs.

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