α-Galactosidase catalyzes the transglycosylation reaction for galactooligosaccharides (GOS) synthesis. However, its strong hydrolytic activity limits the yield of oligosaccharides. Here, semirational design was used to engineer α-galactosidase AglB from Lactobacillus amylolyticus L6, generating three mutants with improved transglycosylation. K480R and H203P exhibited different functional characteristics. The hydrolytic activity of the K480R mutant was significantly reduced by 90.37%, thereby increasing the maximum GOS conversion rate to 34.30%, marking a 3.32-fold increase compared to WT. In contrast, the hydrolytic activity of the H203P mutant was increased by 2.83-fold. Molecular dynamics simulations and substrate-binding pocket analysis revealed that the K480R mutation rendered the active pocket more rigid and shallower, which hindered the access of water molecules through steric hindrance. Conversely, the H203P mutation enhanced the local flexibility at the pocket entrance, thus facilitating nonspecific hydrolysis. This study shifted the functional balance of AglB from hydrolysis toward transglycosylation, providing a high-performance catalyst for GOS production.

This work investigates the microhydration of the beryllium trifluoride anion (BeF3-) with up to three water molecules (BeF3-(H2O)n where n = 1-3). Full geometry optimizations and harmonic vibrational frequencies were computed on various BeF3-(H2O)n stationary points using density functional theory methods (B3LYP-D3BJ, B3LYP, ωB97XD, and M06-2X) as well as the CCSD(T) and MP2 ab initio methods with a triple-ζ correlation-consistent basis set augmented with diffuse functions on all non-hydrogen atoms (haTZ). One BeF3-(H2O)1, five BeF3-(H2O)2 and 11 BeF3-(H2O)3 minima were identified, most of which have not been reported in the literature to date. Two of the new BeF3-(H2O)3 configurations have lower electronic energies than the previously reported trihydrate structure by nearly 1 kcal mol-1, but the previous structure has the lowest energy when harmonic zero-point vibrational energies are included. For the mono- and dihydrates, the water molecule(s) prefer to bind directly to the beryllium trifluoride anion via double ionic hydrogen bonds (DIHBs) to form planar structures with C2v symmetry. With the introduction of a third water molecule, the hydration pattern associated with the lowest-energy structure (with C3 symmetry) changes from solely DIHBs to a hydrogen-bonded network that also includes water-water interactions. The CCSD(T)/haTZ electronic dissociation energies for the BeF3-(H2O)n global minima are 16.0, 30.1, and 43.6 kcal mol-1 for n = 1, 2, and 3, respectively, and these values decrease by about 5% when a counterpoise procedure is applied. The CCSD(T)/haTZ harmonic OH stretching frequencies of H2O decrease appreciably when donating hydrogen bonds to BeF3- and/or H2O molecules. The magnitude of these shifts is strongly dependent on the hydration motif. For the symmetric structures exhibiting only DIHB contacts, the largest shifts at this level of theory are -168 cm-1 for n = 1 (C2v), -138 cm-1 for n = 2 (C2v), and -122 cm-1 for n = 3 (D3h). In contrast, the C3 trihydrate global minimum also has hydrogen bonding between the water molecules, and the largest shift exceeds 200 cm-1. The magnitude can even exceed 300 cm-1 in structures with an H atom that does not participate in hydrogen bonding.

Understanding the thermodynamic driving force behind the pH-controllable interfacial hydration of strong polyelectrolyte brushes (SPBs) is crucial yet challenging. Using the poly(styrenesulfonate) (PSS) brush as a model system, we elucidate this thermodynamic mechanism by employing advanced femtosecond sum frequency generation vibrational spectroscopy (SFG-VS). SFG-VS identifies the hydrogen bond interactions between the bound hydronium counterions and the grafted PSS chains, along with the ordering of water molecules at the PSS brush surface. As pH increases, more hydrogen bonds are formed between the interfacial water molecules and the PSS brush accompanying the disruption of the integrated hydrogen-bond network inside the brush, concurrently enhancing the ordering of interfacial water molecules, thereby leading to the interfacial hydration of the PSS brush with negative changes in both enthalpy (ΔH < 0) and entropy (ΔS < 0). Consequently, the pH-controllable interfacial hydration of the PSS brush is consistent with enthalpically driven hydration. Moreover, this pH-controllable, enthalpically driven interfacial hydration may extend to other SPB systems, enabling the key properties of SPBs pH-responsive. This work provides a thermodynamic perspective on the pH-controllable interfacial hydration of SPBs, and will pave the way for novel applications of SPBs in material science.

The free OH moiety unique to the air/water interface is studied by interferometric two-dimensional heterodyne-detected vibrational sum-frequency generation (2D HD-VSFG) spectroscopy. The 2D spectrum immediately after vibrational excitation exhibits cross-peaks between the free OH main peak (∼3700 cm-1) and its shoulder band (∼3650 cm-1), revealing that the shoulder band appears due to vibrational coupling with the free OH stretch within a single interfacial water molecule at the topmost water layer. The relative amplitude of the cross-peak increases with decreasing pump frequency, accompanied by the redshift of the bleach of the free OH main peak. This indicates that the free OH stretch band is inhomogeneously broadened and that the magnitude of the vibrational coupling significantly varies among the subensembles of the free OH.

Biorefining cellulose, a major constituent of agricultural residue cell walls, into high-value chemicals improves agriculture's economic and environmental performance. Solvents play a crucial role in determining the selectivity and yield of cellulose hydrolysis products, yet the underlying mechanism of this control remains elusive. This study integrates calculational chemistry and experimental data to elucidate at the molecular level the specific roles of solvent molecules in cellulose hydrolysis. In the composite solvent γ-valerolactone/water, a cellulose conversion of 95.0% and a levulinic acid yield of 65.8% were achieved. Under kinetic control, water molecules both promote catalytically active species generation and, through intermolecular interactions, facilitate their reactive binding with glucose intermediates. GVL solvent molecules stabilize catalytically active species and product molecules via confinement enrichment and electronic structure regulation. This work reveals the decisive role of solvent effects in sustainable biorefining, paving the way for dramatically boosting the agricultural residue utilization efficiency.

The features of using field-effect transistors (FETs) based on a reduced graphene oxide (RGO) film deposited on the surface of anodically and thermally oxidized porous silicon as photodetectors and gas adsorption sensors have been investigated. An increase in the efficiency of the created FETs was found as a result of thermal oxidation of the porous layer or deposition of an additional SiO₂ layer on the surface of anodically oxidized porous silicon. It has been established that the photo- and adsorption sensitivity of the RGO-based FETs depends on both the quality of the insulating layer and the presence of a protective SiO₂ coating on the RGO film. In particular, the FETs with an anodic oxidized porous silicon insulating layer are characterized by the highest photosensitivity. Conversely, the graphene FET with thermally oxidized porous silicon is almost insensitive to visible light but demonstrates maximum response to the adsorption of water molecules. The SiO₂ protective layer has almost no effect on the photosensitivity of RGO-based FETs but significantly reduces the influence of the atmosphere on their conductivity.

Water's ability to form hydrogen bond networks underlies its unique properties. Microhydration, which is the binding of a few water molecules to solutes, can significantly alter both the hydrogen bond network compared to pure water and the solute's structure. Here, we highlight selected solute-water complexes that display notable internal dynamics and structural changes upon microhydration, studied using a tight combination of rotational spectroscopy and quantum-chemical calculations. We also demonstrate how nuclear quadrupole coupling effectively probes changes in the electronic environment during microhydration, offering insights into processes such as acid dissociation.

Ten compounds have been prepared among them six different dioxido(pyridine-2,6-dicarboxylato)vanadate(V) compounds with piperazinium (H2pip2+) (1·6H2O), methylpiperazinium (H2mepip2+) (2·5H2O), ethylpiperazinium (H2etpip2+) (3·3H2O), isopropylpiperazinium (H2isopip2+) (4·H2O), phenylpiperazinium (Hphepip+) (5∙H2O) and thiomorpholinium 1-oxide (HtmorO+) (6·2,6-H2pydc·2H2O) cations as counterions as well as methylpiperazinium (H2mepip2+) salt of a mixed valence vanadium [VO(2,6-pydc)-(μ-O)-VO(H2O)(2,6-pydc)]− complex (7), thiomorpholin-4-ium vanadate (Htmor)VO3 (8), hexa(thiomorpholin-4-ium) decavanadate hexahydrate (Htmor)6[V10O28]·6H2O (9·6H2O) and organic salt cocrystal thiomorpholin-4-ium 6-carboxypicolinate pyridine-2,6-dicarboxylic acid (Htmor)+(2,6-Hpydc)−∙(2,6-H2pydc)·2H2O (10·2H2O) via different pathways starting either from pyridine-2,6-dicarboxylic acid or its esters, and were structurally characterized by single-crystal X-ray diffraction. Extended hydrogen bonding interactions are present due to the presence of organic cations as well as due to the diverse roles of water molecules in the hydrogen bonding network. Centrosymmetric hydrogen bonding was found to be an important motif, and diverse supramolecular patterns were also observed due to a wide variety of C–H···O and π···π interactions stabilizing the crystal lattices.

Salicylate 1,2-dioxygenase (SDO), a ring-fission nonheme dioxygenase enzyme, catalyzes the regioselective oxidation of gentisic acid (GTQ) and salicylic acid (SAL) in the presence of molecular oxygen. Wild-type SDO from Pseudaminobacter salicylatoxidans exhibits higher catalytic efficiency with GTQ compared to SAL. To elucidate the factors underlying this difference, classical molecular dynamics simulations were performed on wild-type SDO complexed with GTQ and SAL. The simulations revealed that a water molecule anchored by the ARG127 residue adjacent to molecular oxygen is present with the GTQ substrate, unlike with SAL. Further, hybrid quantum mechanics/molecular mechanics calculations indicated that alkylperoxo intermediate formation is more favorable with GTQ, highlighting the crucial role of the 5́'-OH group, which is absent in SAL, in SDO's differential catalytic activity.

We have investigated the dynamics of vibrational spectral diffusion, hydrogen bonds and orientational relaxation of water in glycerol-water mixtures of varying concentration. We have looked at how these water dynamical properties are affected by glycerol in different solvation environments through calculations of the linear and two dimensional infrared (2DIR) spectra, and various time correlation functions. We have focused on the low concentration regime with the glycerol mole fraction (xGLC) going up to 0.12. It is found that the linear infrared spectra do not show any changes in the stretch frequencies of water in this concentration regime, since the OH groups of glycerol molecules provide a hydrogen bonding environment similar to that of water OH groups. However, the dynamics of spectral diffusion calculated from 2DIR spectra at the non-Condon level and the frequency time correlation function (FTCF) of water molecules that are present in the hydration shells of two or more glycerol molecules, referred to as the trapped water, show a noticeable change in the rate of slowing down beyond the glycerol mole fraction of xGLC ≈ 0.075. A similar change in the dynamics is also observed for orientational relaxation of trapped water molecules at the same glycerol concentration, which we refer to as the cross-over concentration for these mixtures. The dynamics of bulk water and also of those in the hydration shell of a single glycerol molecule are found not to exhibit any such crossover with increase of glycerol concentration. The distinct dynamical behavior of trapped water with variation of glycerol concentration can be linked to the glycerol induced effects on the dynamics of water-water hydrogen bonds.

Seawater electrolysis is considered a promising approach for large scale sustainable hydrogen production. However, its complex ionic environment often causes precipitation formation and Cl- poisoning of active sites, severely hindering the hydrogen evolution reaction (HER) kinetics. Here, we construct a low-Pt-doped and vacancy-rich cobalt oxide catalyst (Pt-CoO x ), in which vacancy rich asymmetric Pt-O-Co bridge structure induces charge polarization and strengthens the Lewis acidity of Co sites, thereby enabling selective OH- adsorption while suppressing chloride ion (Cl-) adsorption and effectively preventing poisoning of the Pt active centers. In situ characterization and theoretical calculations reveal that the asymmetric Pt-O-Co bridge with rich O vacancies achieves ideal hydrogen adsorption energetics and disrupts the hydrogen bond network of interfacial water molecules, thereby lowering the energy barrier for water dissociation and preventing the formation of precipitates. Benefiting from above, Pt-CoO x requires only 160.22 mV to deliver 500 mA cm-2 in alkaline seawater and maintains excellent durability in natural seawater. When integrated into an anion exchange membrane water electrolyzer (AEMWE), the catalyst achieves an industrial level current density of 1 A cm-2 at 1.97 V and operates stably for more than 100 hours at 500 mA cm-2.

Low-energy electron interactions with biomolecules play a central role in radiation-induced chemistry. Initially, electrons are attached to the building blocks of biomolecules, leading to electronic resonances. Here, we present a theoretical investigation of π resonances in microsolvated uracil anion clusters using a combination of multireference and equation-of-motion coupled-cluster electronic structure methods. In addition to the bound anionic ground state, we identify three resonances. Our results are in excellent agreement with recent experiments, predicting a progressive stabilization of all anionic states with increasing numbers of water molecules, while the excitation energies of the anion remain almost constant with solvation. Importantly, our calculations show that the second low-lying π resonance has two-particle one-hole Feshbach resonance character, rather than the one-particle shape character assigned in prior experimental interpretation. Distinguishing between shape and Feshbach resonances is crucial for understanding low-energy electron-molecule interactions, as these states exhibit very different electronic structures, lifetimes, and, therefore, decay mechanisms. Overall, these findings highlight the essential role of high-level electronic-structure theory in interpreting transient states of anions in microsolvated biomolecular systems.

Allosteric effects are critical for protein function. The mechanisms by which allosteric effects propagate in cellular environments remain intriguing yet unresolved questions. In this study, we investigated the allosteric effects involved in a protein-protein binding process within Escherichia coli cells. Mutations far away from the binding interface were introduced, which alter the affinity through allosteric effects. The results indicate that entropy contributes favorably to the allosteric effect in cellular contexts. This entropy-driven allosteric effect is also corroborated by molecular dynamics (MD) simulations, which underscore the significance of the protein solvation water. The crowded macromolecules help to restrain solvation water, and the release of these water molecules creates a positive entropic gain, which in turn generates an allosteric effect in cells.

The increasing concentration of atmospheric CO2 demands the development of advanced and sustainable materials for carbon capture. Peptide-based nanostructures have emerged as promising candidates due to their tunable chemistry, biocompatibility, and ability to self-assemble into ordered supramolecular architectures. In this work, we investigate the adsorption behavior of CO2 on self-assembled A6H and A6R peptide membranes through classical molecular dynamics simulations. The A6H and A6R sequences consist of six alanine residues capped by a terminal histidine or arginine residue, respectively, and self-assemble into stable β-sheet membrane structures whose surface charge distribution and hydration organization are governed by the nature of the terminal residue. After equilibrating the membranes in an aqueous medium, water molecules were removed, and CO2 was introduced into the simulation box to evaluate gas-surface interactions under idealized gas-phase contact conditions. The results reveal distinct adsorption mechanisms governed by headgroup chemistry: the imidazole-terminated A6H interface exhibits preferential electrostatic and hydrogen-bond-driven interactions with CO2, whereas the guanidinium-terminated A6R membrane, characterized by a higher surface charge density, promotes enhanced electrostatic attraction and a larger number of CO2 binding events. These findings highlight how the chemistry of peptide terminal residues modulates CO2 affinity at ordered, self-assembled membrane interfaces, underscoring the potential of bioinspired peptide membranes as tunable platforms for carbon capture. By focusing on experimentally validated supramolecular architectures rather than peptide aggregates or hybrid systems, this study provides molecular-level insights that can inform the rational design of peptide-based sorbent materials for sustainable CO2 sequestration.

The photocatalytic hydrogen evolution reaction (HER) in seawater has emerged as one of the most promising technologies for the production of clean energy, yet the photocatalysts still suffer from severe salt-induced corrosion and limited mass transfer, limiting their practical applications. In addition, compared with conventional suspension-based photocatalytic systems, membrane/film-based photocatalytic systems could help to disperse catalytic nanoparticles well, realizing high photocatalytic efficiency and stability. However, the mass transportation of water molecules may be inhibited in many membrane- or film-based photocatalytic systems. Herein, we embed and immobilize Pt/TiO2 particles in a perfluorosulfonic acid resin (Nafion) film coated on glass fiber paper for enhanced activity and stability of the photocatalytic HER in simulated seawater. The flexible Nafion film embedded with Pt/TiO2, referred to as Nafion-Pt/TiO2, demonstrated outstanding photocatalytic hydrogen evolution in simulated seawater. A remarkable hydrogen production rate of 7.689 mmol·g-1·h-1 was realized, representing a 5.37-fold enhancement compared with that of bare Pt/TiO2. This enhancement can be attributed to the Nafion-induced improvements in charge separation and a localized photothermal effect enabled by thermal confinement. Furthermore, the Nafion-Pt/TiO2 system showed a superior stability, and 99.3% of its initial catalytic activity was retained after five consecutive photocatalytic cycles. This study provides valuable insights into enhancing both the activity and the stability of photocatalytic hydrogen production in seawater.

Hydrophobic Mn/ZSM-5 modification for highly efficient O3 decomposition under humidity conditions.

Micro-structural analysis of aqueous uranyl ions (UO22+) during the course of forward and back extraction in A biphasic system using all atom atomistic simulations.

The first bromodomain of the BET protein BRDT (BRDT-BD1) possesses a unique Arg54 residue at the terminus of the ZA channel, absent in other BET family members. We explored this structural uniqueness with 23 analogs of the BET/kinase inhibitor SG3-179, each bearing an amino acid side chain to enable potential interactions between the positively charged arginine group and the negatively charged carboxylate groups. In an AlphaScreen assay, serine analog 13 showed 35-fold selectivity for BRDT-T over BRD4-T. The BRDT-BD1 cocrystal structure with glutamic acid analog 14 showed no interaction with Arg54, suggesting that the observed preference may be related to differences in the structured water molecules. Compound 13 displayed exceptional in vitro metabolic stability but had limited cellular permeability in MDCK-MDR1 cells. Compounds 13 and 14 are among the best BRDT-BD1-preferring inhibitors reported to date and demonstrate a significant step toward identifying highly selective BRDT inhibitors for male contraception.

TraH, a fungal decarboxylase from Penicillium crustosum, belongs to the isopenicillin N synthase (IPNS) subfamily of non-heme iron/α-ketoglutarate (αKG)-dependent enzymes. IPNS enzymes are characterized by N- and C-terminal insertions that can reshape the active site. However, the functional and mechanistic roles of these elements, particularly in fungal decarboxylases, remain largely unexplored. Here, we report crystal structures of TraH in complex with various substrates, revealing a N-terminal loop, serving as lid and undergoes substrate-dependent dynamic conformational rearrangements. Upon binding of crustosic acid, this lid loop forms a hydrogen-bonding network to stabilize a water molecule, which mediates interaction between the conserved K191 residue in the DSBH (double-stranded β-helix) core and the substrate. Mutagenesis and QM/MM metadynamics simulations suggest that proton transfer from K191 is mediated by water molecules stabilized by the lid loop, supporting a decarboxylation mechanism distinct from the canonical strategy of direct carboxylate stabilization by DBSH core-located basic residues in other αKG-dependent decarboxylases. Interestingly, this loop is dispensable for the desaturation of crustosic acid methyl ester, thereby pinpointing its essential role to the precise positioning of the carboxylate substrate for proton transfer during decarboxylation. Evolutionary and structural analyses reveal significant variation in lid loop composition across IPNS enzymes, indicating its contribution to substrate recognition and functional diversification. Overall, our findings uncover a regulatory element in iron/αKG-dependent enzymes and offer insights into how non-core structural elements contribute to catalytic mechanism and evolution.

Cryo-electron microscopy (cryo-EM) is a widely used technique for determining macromolecular structures at near-atomic resolution. The theoretical lower limit of particle sizes suitable for cryo-EM structural analysis is estimated to be 38 kDa; typical constraints involve factors such as image contrast and particle alignment accuracy. In this study, we present cryo-EM structures of two protein-ligand complexes near this lower size threshold. First, the structure of the maltose-binding protein complexed with maltose, with a structurally ordered mass of 40.8 kDa, was determined at a resolution of 2.4 Å; both the maltose and water molecules were clearly identified in this structure. The second structure was the kinase domain of human PLK1 complexed with onvansertib, with a structurally ordered mass of 31.6 kDa, below the theoretical 38 kDa limit; this domain was determined at a resolution of 3.4 Å using a gold-supported grid in the presence of β-octyl-glucoside. The density map clearly shows the backbone of PLK1 secondary structure, and the onvansertib. These results demonstrate that cryo-EM can be effectively employed to determine structures of small proteins or domains, and to perform structure-based drug screening for small proteins, without requiring structural fiducials for particle alignment.