Structural basis for ion selectivity revealed by high-resolution crystal structure of Mg2+ channel MgtE

Takeda, H.; Hattori, Motoyuki; Nishizawa, Takashi; Yamashita, Keitaro; Shah, Syed Tasadaque Ali; Caffrey, Martin; Maturana, Andrés D.; Ishitani, Ryuichiro; Nureki, Osamu

doi:10.1038/ncomms6374

Cited by 45 publications

(68 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, we note that the surface of ceria, even in the absence of strain, is already enriched in Ce 3+ compared with the bulk4647. Straining the lattice leads to further enrichment of surface oxygen vacancies and Ce 3+ .…”

Section: Resultsmentioning

confidence: 73%

Equilibrium oxygen storage capacity of ultrathin CeO2-δ depends non-monotonically on large biaxial strain

et al. 2017

View full text Add to dashboard Cite

Elastic strain is being increasingly employed to enhance the catalytic properties of mixed ion–electron conducting oxides. However, its effect on oxygen storage capacity is not well established. Here, we fabricate ultrathin, coherently strained films of CeO2-δ between 5.6% biaxial compression and 2.1% tension. In situ ambient pressure X-ray photoelectron spectroscopy reveals up to a fourfold enhancement in equilibrium oxygen storage capacity under both compression and tension. This non-monotonic variation with strain departs from the conventional wisdom based on a chemical expansion dominated behaviour. Through depth profiling, film thickness variations and a coupled photoemission–thermodynamic analysis of space-charge effects, we show that the enhanced reducibility is not dominated by interfacial effects. On the basis of ab initio calculations of oxygen vacancy formation incorporating defect interactions and vibrational contributions, we suggest that the non-monotonicity arises from the tetragonal distortion under large biaxial strain. These results may guide the rational engineering of multilayer and core–shell oxide nanomaterials.

show abstract

Section: Resultsmentioning

confidence: 73%

Equilibrium oxygen storage capacity of ultrathin CeO2-δ depends non-monotonically on large biaxial strain

et al. 2017

View full text Add to dashboard Cite

show abstract

“…This feedback inhibition can provide a rapid shutoff of uptake when Mg(II) levels are sufficient. However, high concentrations of Mn(II) may inappropriately lock MgtE in the closed conformation, which potentially leads to intracellular Mg(II) deficiency 124 . To date, there are surprisingly few examples of allosterically regulated transport systems for other metals in bacteria, which may reflect the difficulty of evolving allosteric sites of sufficient specificity to prevent dysregulation by non-cognate metals.…”

Section: Metalloregulatory Systemsmentioning

confidence: 99%

“…Metal ions might also antagonize metal uptake by inappropriately signaling sufficiency to transporters that are regulated allosterically. One possible example is the Mg(II) importer MgtE, which is potentially inhibited by binding of Mn(II) to its allosteric regulatory site 124 (BOX 3). …”

Section: Metal Ion Intoxication and Its Consequencesmentioning

confidence: 99%

Metal homeostasis and resistance in bacteria

2017

View full text Add to dashboard Cite

Metal ions are essential for many reactions, however, metal excess can be toxic. In bacteria, metal limitation activates pathways for import and mobilization of metals, whereas metal excess induces efflux and storage. In this Review, we highlight recent insights into metal homeostasis, including protein- and RNA-based sensors that interact directly with metals or metal-containing cofactors. The resulting transcriptional response to metal stress is deployed in a stepwise manner, and is reinforced by post-transcriptional regulatory systems. Metal limitation and intoxication by the host is an evolutionarily ancient strategy to limit bacterial growth. The details of the resulting growth restriction are beginning to be understood, and appear to be organism-specific.

show abstract

“…Ions selected to test the hydration mimicry concept include both monovalent alkali metal ions (Li, Na, K, Rb) and divalent alkaline earth metal ions (Mg, Ca, Sr, Ba). Protein binding sites analyzed here come from a celebrated bacterial potassium-selective channel (KcsA) (15), the recently discovered bacterial magnesium-selective transporter (MgtE) (36,94), and the voltage-gated bacterial calcium-selective channel (CavAb) (37,82).…”

Section: Specific Ions and Proteins For Hydration Mimicry Analysismentioning

confidence: 99%

Hydration Mimicry by Membrane Ion Channels

Chaudhari

Vanegas

Pratt

et al. 2020

Annu. Rev. Phys. Chem.

View full text Add to dashboard Cite

Ions transiting biomembranes might pass readily from water through ion-specific membrane proteins if those protein channels provide environments similar to the aqueous solution hydration environment. Indeed, bulk aqueous solution is an important reference condition for the ion permeation process. Assessment of this hydration mimicry view depends on understanding the hydration structure and free energies of metal ions in water to provide a comparison for the membrane channel environment. To refine these considerations, we review local hydration structures of ions in bulk water, and the molecular quasi-chemical theory that provides hydration free energies. In that process, we note some current views of ion-binding to membrane channels, and suggest new physical chemical calculations and experiments that might further clarify the hydration mimicry view.

show abstract

Structural basis for ion selectivity revealed by high-resolution crystal structure of Mg2+ channel MgtE

Cited by 45 publications

References 41 publications

Equilibrium oxygen storage capacity of ultrathin CeO2-δ depends non-monotonically on large biaxial strain

Equilibrium oxygen storage capacity of ultrathin CeO2-δ depends non-monotonically on large biaxial strain

Metal homeostasis and resistance in bacteria

Hydration Mimicry by Membrane Ion Channels

Contact Info

Product

Resources

About