Water Molecules Research Articles

Study on the phase transition characteristics of nano-hydrated salts based on molecular dynamics simulations

Hydrated salts possess great competitiveness in terms of enhancing utilization efficiency of heat due to large densities of heat storage and low costs. However, the existence of supercooling degree is the common phenomenon for hydrated salts, which might restrict the application prospects in partial fields. This work focuses on hydrated salts with relatively larger latent heats, namely Na2CO3·10H2O and Na2HPO4·14H2O in the absence and presence of SiO2 as well as eutectic hydrated salt prepared with 40 wt% Na2CO3·10H2O and 60 wt% Na2HPO4·12H2O. Their melting/solidification temperatures were determined and the supercooling behavior was analyzed based on molecular dynamics simulations. The simulation results of melting/solidification temperatures present small deviations of 0.17–3.24 ℃ in comparison with experimental data. Additionally, the aggregation phenomenon among salt ions and dispersion phenomena among water molecules and between water molecules and salt ions for supercooled liquid hydrated salts are revealed, which are attributed to stronger electrostatic interactions and weaker van der Waals interactions as well as lower binding energies. Moreover, SiO2 not only lowers melting temperatures due to its higher thermal conductivity than hydrated salts and the existence of micro-convection, but affects solidification behavior of hydrated salts. The different influences of SiO2 on solidification temperatures of Na2HPO4·14H2O and Na2CO3·10H2O were associated with dispersion degree between water molecules and salt ions around SiO2, which would be attributed to different strengths of interaction forces between SiO2 and salt ions. On these bases, this work provides new perspectives for clarifying phase change characteristics of nano-hydrated salts.

Molecular dynamics mechanism of incorporating ZnO with varying particle sizes into ECTFE coatings and its impact on corrosion resistance

A composite coating of zinc oxide/chlorotrifluoroethylene copolymer (ZnO/ECTFE) was prepared on the surface of carbon steel via electrostatic spraying and heat treatment at 260 ℃. The influence of ZnO particle size variations on the anticorrosive properties of ECTFE coating was investigated by characterizing the microstructure, adhesion, hydrophilic/hydrophobic properties, electrochemical corrosion performance, as well as the dynamics simulation analysis on water molecule and chloride ions diffusion in the coating. The results show that the ECTFE coating incorporated with 100nm ZnO has the highest surface roughness (Roughness coefficient Ra = 30.6nm), the most robust adhesion (Bonding pull-out strength = 5.22MPa), and the lowest corrosion current density after a 90-day immersion (Icorr,90d = 4.05 × 10⁻⁸ A∙cm⁻²). These improvements represent an increase of 81.67% and 59.9% compared to the pure copolymer coating (Icorr,90d = 2.21 × 10⁻⁷ A∙cm⁻²) and the coating incorporated with 200nm ZnO (Icorr,90d = 1.01 × 10⁻⁷ A∙cm⁻²), respectively. This phenomenon can be attributed to the addition of small-sized ZnO, which enhances the density of the coating, induces a hydrophobic transition on its surface, strengthens the double electric layer effect, thereby improving its resistance against water molecule and chloride ions diffusion and ultimately enhances the corrosion resistance.

A comparative study of different soybean oil forms on the physicochemical properties of surimi myofibrillar protein gel: The role of soybean protein isolate and κ-carrageenan

Natural soybean oil, Pickering emulsion, high-internal-phase emulsion (HIPE), and emulsion gel were prepared to investigate their effects on the physicochemical properties of surimi myofibrillar protein gels. Their effects on gel strength ranked as: emulsion gel > Pickering emulsion > HIPE > soybean oil. At the same oil content, the emulsion gel exhibited higher G' than the other forms whereas natural oil exhibited the lowest G', and T22 was smaller in the emulsion gel group, indicating that the emulsion gel enhanced the interaction between water molecules and protein macromolecules. FT-IR testified that 9 % natural oil reduced the β-sheet content to 26.34 %, whereas Pickering emulsion, HIPE, and emulsion gel recovered the β-sheet content to 31.30 %, 36.17 %, and 32.69 %, respectively. Emulsion gel led to fewer voids, and the oil droplets in emulsion gel were more regularly spherical and homogeneously dispersed in the gel matrix, which might be attributed to the filling effects as well as “bridging action” of soybean protein isolate and κ-carrageenan within surimi proteins. In conclusion, we demonstrated emulsion gel as a good replacer to mitigate the negative effect of oil on the texture and structure of surimi gels, which would be a promising approach for oil supplementation in surimi production.

Study on hyaluronic acid aquaphotomics-from one dimension to two dimension analysis.

Hyaluronic acid (HA) is widely used in cosmetics because of its unique hygroscopic properties. However, it is difficult to characterize the interactions between HA and water molecules in the skin. In this study, we developed a fast and nondestructive method for visualizing skin water species based on aquaphotomics to elucidate the mechanism by which HA affected water species. The first HA-water system was introduced to investigate the relationship between HA and water species based on near-infrared (NIR) spectroscopy and aquaphotomics. NIR-hyperspectral imaging was then applied to characterize the distribution of different water species in the skin. The HA-water system results indicated that oligo HA had hydration behaviors opposite to those of low molecular weight HA. NIR hyperspectral imaging results showed that the intensity and spatial distribution of each water species within the skin model can be directly characterized by upgrading aquaphotomics from one-dimensional to two-dimensional. Studies showed that HA tetrasaccharides and 600-700kDa HA could maintain the strength of skin water species. In summary, the visual representation of water species distribution enables rapid and nondestructive monitoring of macromolecule hydration with skin which could help cosmetics formulators to optimize their HA formulation to realize their best hygroscopic properties in the future.

Phase equilibrium and separation process of byproduct vinyl acrylate in the ethylene vapor phase method producing vinyl acetate

Vinyl acrylate is one of the byproducts in the ethylene vapor phase method for the production of vinyl acetate (VAc), which not only has a toxic effect on the catalyst but also affects the purity of the product. Currently, phase equilibrium data for vinyl acrylate with water are missing, making the destination of vinyl acrylate in the distillation process uncertain. This has led to a lack of effective removal means, which restricts the optimization of the ethylene vapor phase method. This paper uses a method combining quantum chemistry and molecular dynamics simulation (MD) to investigate the existential form of the water molecule. And based on the ab initio calculation of the first principle, the force field parameters of the special water molecular structure are calculated, and the TIP4P-P force field that can describe the special water structure is established. Using the Gibbs Ensemble Monte Carlo (GEMC) method, the reliability of the improved water molecule force field for modeling the phase equilibrium of a binary system is first verified. Further, vapor–liquid phase equilibrium data for the vinyl acrylate-water binary system at 110 kPa and 150 kPa are calculated and the corresponding x-y and T-x-y phase diagrams are plotted. After performing the thermodynamic consistency test, the phase equilibrium data are fitted to obtain the binary interaction parameters of vinyl acrylate with water. The fitted parameters are applied to the process simulation of the VAc refining process to optimize the conditions and obtain an effective separation scheme for vinyl acrylate. The concentration distribution of vinyl acrylate in the distillation column is investigated, thus clarifying the destination of vinyl acrylate in the distillation process and facilitating the optimization of the ethylene vapor phase method.

A novel layered structure of the heterometallic oxalate compound [NH2(CH3)2]2[NaFe(C2O4)3]·0.33NH(CH3)2·0.33H2O: synthesis, crystal structure and thermal decomposition.

The synthesis, single-crystal X-ray structure determination and thermal analysis are reported for a novel heteronuclear oxalate compound synthesized from a mixture of Fe and Na salts, oxalic acid and N,N-dimethylformamide (DMF) in aqueous solution. The new metallooxalate compound was obtained and identified as a dimethylammonium tris(oxalato)ferrate(III), namely, poly[[bis(dimethylammonium) [tri-μ-oxalato-sodium(I)iron(III)]]-dimethylamine-water (3/1/1)], [NH2(CH3)2]2[NaFe(C2O4)3]·0.33NH(CH3)2·0.33H2O, which crystallizes in the orthorhombic noncentrosymmetric space group C2221. In this novel structure, each Fe atom is hexacoordinated by three non-equivalent bidentate oxalate ligands, while the four Na atoms adopt different coordination numbers, i.e. 6, 7 and 8. The structure consists of bimetallic anionic A layers, {[NaFe(C2O4)3]2-}n, displaying a layered structure with infinitely linked Fe2Na2 tetramers on the ab plane. Two kinds of bimetallic parallel layers (A1 and A2) are present alternately and are found to be staggered, while only the A2 layer is crossed by a twofold axis parallel to the a axis through two Na atoms. The [NH2(CH3)2]+ (HDMA) cations occupy the voids between the anionic layers, while the free molecules, i.e. NH(CH3)2 (DMA) and H2O, are located between two different anionic layers. In addition to ionic bonds, the stability of the structure is ensured by hydrogen-bond interactions involving the oxalate ligands and the nitrogenous and water molecules. The layered structure appears to be different in the family of oxalate-bridged NaI-FeIII compounds. It is in agreement with the predicted 2D or layered structure of bimetallic complexes containing anionic tris(oxalato)metallate(III) with the [XR4]+ counter-ion template (X= N, P or S, and R= alkyl group or H). The thermal decomposition of the compound shows the final residual product to be NaFeO2.

The engineered interfacial Pd-O-Ti sites on the TiO2 nanobelts to accelerate water dissociation for the alkaline hydrogen evolution

Electrochemical water splitting derived by the renewable electricity is one attractive route to produce the green hydrogen. The hydrogen evolution reaction (HER) at the cathode side under the alkaline condition is relatively difficult compared with the acidic, because there is a rate-determining step of breaking strong H-OH bonding in the water molecular. Herein, the ultrafine Pd nanoparticles are uniformly distributed on the TiO2 nanobelts (PdNPs/TiO2) by the pulsed laser deposition to expose the abundant interfacial sites, showing a lower HER overpotential of 71 mV at the current density of -10 mA cm-2 in 1 M KOH. The interfacial Pd-O-Ti structure on PdNPs/TiO2 provides the direct contact between active phase and the water molecules, contributing to break H-OH bond. At the same time, a selective adsorption of H on Pd and OH intermediate on TiO2 is achieved in the interfacial Pd-O-Ti sites under the alkaline HER, optimizing the whole catalytic dynamic.

A Gradient Photothermal Hydrogel with Carbon-Dots Deposited Molybdenum Disulfide Nanoflowers as Photothermal Centers for Efficient Solar-Driven Water Evaporation and Treatment

Given the urgency of water pollution and freshwater scarcity, the pursuit of efficient and clean desalination techniques has gained prominence. In this study, a multi-defective molybdenum disulfide nanoflower was synthesized within a carbon-dots solution environment, named CDs/MoS2, exhibiting exceptional photothermal and catalytic properties. Relying on the excellent photothermal properties, antibacterial rates of up to 94% and 99% against Staphylococcus aureus and Escherichia coli. Additionally, the CDs/MoS2 nanoflowers exhibited a remarkable removal efficiency of 91% for high concentrations of methylene blue (MB) through photodegradation. A gradient photothermal composite hydrogel (CDs/MoS2@PVA Hydrogel) was designed to serve as a solar-driven clean water generator to isolate drinking water from various non-potable water. The gradient hydrogel effectively enhanced solar energy absorption through light trapping, creating dispersed hot spots to capture and activate water molecules. As a result, it achieved a high evaporation rate of 1.49 kg m-2 h-1 at a solar radiation of 1 kW m-2, with an impressive solar-to-vapor conversion efficiency of 92.5%. The hydrogel was successfully employed in diverse water treatment applications, including desalination, anti-bacteria and removal of organic contaminants from water. This study presents an innovative approach to developing novel solar vapor materials for water purification purposes.

The properties of potato starch with different moisture content treated by cold plasma:Structure, physicochemical and digestive properties

To investigate the effect and mechanism of water on the structure, physicochemical properties, and in vitro digestibility of starch treated with CP, different moisture content (16.7 %, 28.6 %, 37.5 %, 44.4 %, and 50 %, w/w) were used, followed by treatment with CP (40 V, 1 A, 3 mins). Results show that CP treatment preserves the Maltese cross pattern, crystal morphology, and Fourier transform infrared spectroscopy spectra of potato starch. However, significant changes were observed in molecular weight, chain length distribution, average particle size, ordered structure, and relative crystallinity. As moisture content increased, the etching effect on the particle surface intensified, leading to further reductions in molecular weight and ordered structure. Concurrently, amylose content, solubility, relative crystallinity, and resistant starch content increased. At higher water levels, water molecules exhibited protective effects, mitigating CP-induced structural damage by reducing etching and loss of molecular weight. These findings suggest that the role of water in CP treatment is complex and provide insights into the interaction between CP and water in starch properties, highlighting its potential applications in starch-based foods.

Lactobacillus fermented chickpeas: Improving dough process quality and biscuit nutritional value

This study aimed to examine the impact of lactobacillus fermented chickpeas (LFC) on dough quality and assess their application potential in biscuits. The results of rheological properties showed that LFC significantly increased the storage modulus (G') and loss modulus (G'') of the dough, with a greater increase in G'. The textural analysis showed that the LFC significantly increased the hardness of the dough before and after fermentation. In the low-field NMR analysis, LFC enhanced the bound water content of the dough and reduced the mobility of the water molecules. Furthermore, the network structure of gluten proteins was weakened by LFC, resulting in more exposed starch. In vitro protein digestibility increased by 28.01% at the gastric end and 11.76% at the intestinal end of LFC-biscuits as compared to chickpea biscuits. It was associated with lactobacilli fermentation reducing phytic acid and trypsin inhibitor activity in chickpeas. Moreover, the protein content of the biscuits has been increased (33.26%) and their free amino acid composition has been optimized. The hardness, brittleness, and specific volume of biscuits were significantly enhanced by LFC, with well sensory acceptance. These findings will enrich the theory of lactobacilli fermentation of legumes and inspire its application in baked foods.

Inhibitory effect of different degree of polymerization inulin on the retrogradation of rice starch gels and fresh rice noodles

This experiment investigated the effects of inulin (IN) with different degrees of polymerization at various addition levels on the water distribution, textural properties, microscopic and molecular structure, cooking quality, and sensory evaluation of rice starch (RS) and fresh rice noodles (FRN) during storage. The results showed that the addition of three kinds of IN significantly reduced the transverse relaxation time T2 of the starch gels system during storage, effectively combined the water molecules in the system. Meanwhile, the addition of IN reduced the increase of starch gels hardness during storage, inhibiting the retrogradation of the starch gels. Fourier transform infrared results further confirmed that IN could suppress the retrogradation behavior of starch during storage by controlling the rearrangement or recrystallization of starch molecular chains. The scanning electron microscopy results of FRN after 7 d of storage showed that the addition of IN enhanced the water retention capacity of FRN during the retrogradation process, which was consistent with the water distribution results. Furthermore, all three kinds of IN improved the cooking and sensory quality of FRN during storage, and the lower the degree of polymerization, the better the anti- retrogradation effect and the quality of the FRN.

Electro-optical and thermal characterization of copper tartrate crystals grown in silica gel

Copper Tartrate crystals were grown by Gel Growth technique by single diffusion method. Silica gel of Optimum specific gravity was set with tartaric acid at optimum pH and aging period. Band gap of copper tartrate crystal is determined using to be 5.24 eV. In PL spectra broad peak is observed at nearly 367.44186 nm in the range 287 nm to 458 nm along with the sharp, intense transmission maxima peak at wavelength nearly 505.03876 nm which is characteristic of a material composition and electronic band structure. This shows the transparency of it in UV-Visible region and it as a filter in this range TGA analysis concludes that Copper tartrate has loss of one-half water molecule as crystalline water and is stable up to 85.02 ℃DSC analysis assigns the temperature value 314.5 ℃ as melting point and apparent enthalpy of fusion determined is 10.18 mW.

The Effect of Electric Fields on Oxidization Processes at the Air-Water Interface.

At the air-water interface, many reactions are accelerated, sometimes by several orders of magnitude. This phenomenon has proved to be particularly important in water microdroplets, where the spontaneous oxidation of many species stable in bulk has been experimentally demonstrated. Different theories have been proposed to explain this finding, but it is currently believed that the role of interfacial electric fields is key. In this work, we have carried out a quantum chemistry study aimed at shedding some light on this question. We have studied two prototypical processes in which a hydroxide anion transfers its excess electron to either the water environment or a dioxygen molecule. To model the interface, we use a cluster of 21 water molecules immersed in an electric field, and we examine the energetics of the studied reactions as a function of field magnitude. Our results reveal that electric fields close to those estimated for the neat air-water interface (~0.15 V×Å-1) have a moderate effect on the reaction energetics and that much stronger fields (>1 V×Å-1) are required to get spontaneous electron transfer. Therefore, the study suggests that additional factors such as an excess charge in microdroplets need to be considered for explaining the experimental observations.

Hydrated Magnesium Ion-Uracil and Magnesium Chloride-Uracil Clusters Revealed by Ab Initio Study.

The study focuses on the interaction between canonical uracil and its rare tautomers with Mg2+ and MgCl2 in the microcosmic water environment and aims to elucidate how ions interact with nucleobase and the cation-anion correlation effect involved using density functional theory calculations. The structures of the Ura-Mg2+(H2O)0-6 and Ura-MgCl2(H2O)0-6 clusters are characterized and show that the water molecules preferentially interact with Mg2+/MgCl2, and Mg2+ adopts a hexacoordination pattern in both Ura-Mg2+(H2O)0-6 and Ura-MgCl2(H2O)0-6 clusters. When uracil interacts with Mg2+ in (H2O)0-6 environments, it tends to favor the formation of keto-enol structures. However, in the presence of Cl- cooperating with Mg2+, the Ura-MgCl2(H2O)0-6 complexes prefer to form diketo structures. The proton transfer mechanism shows that the initial solvation can promote the change from the keto-enol structure to the diketo structure, which is strengthened by the analysis of the Ura-Mg2+(H2O)6 and Ura-MgCl2(H2O)6 structures in the aqueous phase using the PCM model. Additionally, reduced density gradient, atom in molecules, and energy decomposition analysis combined with charge transfer analysis were carried out to obtain the variation law of the interactions between Mg2+ and Ura with the water number increasing, thereby revealing the interaction mechanism of uracil with magnesium ion and the effect of Cl- on the interaction between Mg2+ and uracil.

Advances in Molecular Dynamics-Based Characterization of Water and Ion Adsorption and Transport in C-S-H Gels

Cementitious material durability is affected by the transport and adsorption of water molecules and ions in the nanopore channels of cement hydration products. Hydrated calcium silicate (C-S-H) accounts for about 70% of the hydration product. It determines the mechanical properties of cementitious materials and their internal transport properties. The molecular dynamics method provides a complementary understanding of experimental and theoretical results. It can further reveal water molecules and ions’ adsorption and transport mechanisms in C-S-H gel pores. This review article provides an overview of the current state of research on the structure of C-S-H gels and the adsorption and transport properties of water molecules and ions within C-S-H gels, as studied through molecular dynamics simulations. This paper summarizes the results of the molecular dynamics-based adsorption transport properties of water molecules and ions in C-S-H gels. The deficiencies in the current study were analyzed, and the fundamental problems to be solved and further research directions were clarified to provide scientific references for revealing the structural properties of C-S-H gels using molecular dynamics.

Substitution of the Axial Type 1 Cu Ligand Affords Binding of a Water Molecule in Axial Position Affecting Kinetics, Spectral, and Structural Properties of the Small Laccase Ssl1.

Multicopper oxidases use Cu ions as cofactors to oxidize various substrates. High reduction potential at Type 1 Cu is considered as crucial for effective catalysis. Previous studies have shown that replacing the axial methionine ligand of the Type 1 Cu with leucine or phenylalanine leads to an increased reduction potential, but not always to higher enzyme activity. Here we present a study on six variants of the small laccase Ssl1 from Streptomyces sviceus, where the axial methionine ligand was substituted, and the effect of the axial ligand on reduction potential, activity, spectral properties and structure was investigated. Absorption, electronic circular dichroism and EPR spectra revealed the presence of a stronger coordinating axial ligand like oxygen, which influences the electronic and catalytic properties more than the nature of the amino acid side chain. The crystal structures of the Ssl1 variants were solved, which show that none of the amino acid side chains coordinate to the Cu. Instead, a water molecule is found in the axial coordination site, which support the spectroscopic data. Our findings highlight the importance of combining structural and spectroscopic methods to investigate the effect of amino acid exchange on multicopper oxidases.

Self-Reinforced Cathode Interface to Prolong the Cyclic Stability of Zn-MnO2 Batteries.

Rechargeable aqueous zinc-ion batteries (RAZIBs) are attracting increasing attention due to their advantages in safety, cost, and energy density. However, the choice of electrode binders when using aqueous electrolytes faces many constraints, as nontoxic and low-cost hydrophilic binders, such as sodium alginate (SA), can lead to electrode damage due to excessive swelling in aqueous solution. Here, by employing double-network hydrogel electrolytes formed by poly(vinyl alcohol) and alginate, the content and activity of water molecules at the electrode-electrolyte interface are reduced, and the mechanical stability of the electrode is reinforced, thereby affording reliable protection to the cathode bonded with SA. The quasi-solid-state interface formed between SA and the gel electrolyte provides stable electrode architecture and smooth ion transport, thus enabling Zn||MnO2 cells to exhibit excellent electrochemical cycling performance even when using hydrophilic binders.

Water and chloride as allosteric inhibitors in WNK kinase osmosensing.

Osmotic stress and chloride regulate the autophosphorylation and activity of the WNK1 and WNK3 kinase domains. The kinase domain of unphosphorylated WNK1 (uWNK1) is an asymmetric dimer possessing water molecules conserved in multiple uWNK1 crystal structures. Conserved waters are present in two networks, referred to here as conserved water networks 1 and 2 (CWN1 and CWN2). Here, we show that PEG400 applied to crystals of dimeric uWNK1 induces de-dimerization. Both the WNK1 the water networks and the chloride-binding site are disrupted by PEG400. CWN1 is surrounded by a cluster of pan-WNK-conserved charged residues. Here, we mutagenized these charges in WNK3, a highly active WNK isoform kinase domain, and WNK1, the isoform best studied crystallographically. Mutation of E314 in the Activation Loop of WNK3 (WNK3/E314Q and WNK3/E314A, and the homologous WNK1/E388A) enhanced the rate of autophosphorylation, and reduced chloride sensitivity. Other WNK3 mutants reduced the rate of autophosphorylation activity coupled with greater chloride sensitivity than wild-type. The water and chloride regulation thus appear linked. The lower activity of some mutants may reflect effects on catalysis. Crystallography showed that activating mutants introduced conformational changes in similar parts of the structure to those induced by PEG400. WNK activating mutations and crystallography support a role for CWN1 in WNK inhibition consistent with water functioning as an allosteric ligand.

Electronic vs optical bandgap of stoichiometric V2O5: Effects of surface transfer doping and electron accumulation layer

The experimental and theoretical bandgap reported for stoichiometric V2O5, a layered semiconductor of great technological importance, spans a wide range of 1.7–4.8 eV. Using combined photoemission, absorption, and photoluminescence measurements, we show that the fundamental electronic gap of V2O5 is 1.85 eV, which is in close agreement with the value of 1.8 eV predicted by the first density functional theory studies, but is lower than the value of 2.2–2.8 eV obtained from optical absorption and photoemission studies. It is shown that this difference between the fundamental and optical gaps is due to the presence of a surface electron accumulation layer, which results in a Burstein–Moss shift of the Fermi level well into the conduction band. The underlying cause of degenerate electron doping is due to “surface transfer doping” by ambient water molecules as a result of the high electron affinity of the semiconductor.

Water and chloride as allosteric inhibitors in WNK kinase osmosensing

Osmotic stress and chloride regulate the autophosphorylation and activity of the WNK1 and WNK3 kinase domains. The kinase domain of unphosphorylated WNK1 (uWNK1) is an asymmetric dimer possessing water molecules conserved in multiple uWNK1 crystal structures. Conserved waters are present in two networks, referred to here as conserved water networks 1 and 2 (CWN1 and CWN2). Here, we show that PEG400 applied to crystals of dimeric uWNK1 induces de-dimerization. Both the WNK1 the water networks and the chloride-binding site are disrupted by PEG400. CWN1 is surrounded by a cluster of pan-WNK-conserved charged residues. Here, we mutagenized these charges in WNK3, a highly active WNK isoform kinase domain, and WNK1, the isoform best studied crystallographically. Mutation of E314 in the Activation Loop of WNK3 (WNK3/E314Q and WNK3/E314A, and the homologous WNK1/E388A) enhanced the rate of autophosphorylation, and reduced chloride sensitivity. Other WNK3 mutants reduced the rate of autophosphorylation activity coupled with greater chloride sensitivity than wild-type. The water and chloride regulation thus appear linked. The lower activity of some mutants may reflect effects on catalysis. Crystallography showed that activating mutants introduced conformational changes in similar parts of the structure to those induced by PEG400. WNK activating mutations and crystallography support a role for CWN1 in WNK inhibition consistent with water functioning as an allosteric ligand.