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The G‐protein‐coupled human cannabinoid receptor 1 (CB1) is a promising therapeutic target for pain management, inflammation, obesity, and substance abuse disorders. The structures of CB1‐Gi complexes in synthetic agonist‐bound forms have been resolved to date. However, the commercial drug recognition and Gq coupling mechanisms of CB1 remain elusive. Herein, the cryo‐electron microscopy (cryo‐EM) structure of CB1‐Gq complex, in fenofibrate‐bound form, at near‐atomic resolution, is reported. The structure elucidates the delicate mechanisms of the precise fenofibrate recognition and Gq protein coupling by CB1 and will facilitate future drug discovery and design. [ABSTRACT FROM AUTHOR]

In this paper, the Delayed Detached‐Eddy Simulation (DDES) model is used to simulate the cloud cavitation process and the flow field distribution characteristics in the three‐dimensional cavitating chamber with a sudden change channel. The effect of cavitation evolution on the flow field is investigated by the change of vacuole volume fraction and the distribution of physical quantities in the flow field. And the Q criterion is introduced to identify the vortex structure and its variation. The results show that the evolution of cavitation presents periodic characteristics, but in a period, the flow field distribution, vortex structure, and vortex intensity under different cavitation states are different. In the stage of bubble growth, falling off, bubble cluster breaking, and separation, the vortex size is large and the vortex intensity is high, making the flow field show drastic fluctuations. However, in the stage of bubble mass integration, the flow field fluctuation is relatively weak, and the pressure fluctuation law is consistent with the bubble shedding frequency. In addition, the Q criterion indicates that the high‐strength vortices are mainly concentrated in the throat, as the degree of cavitation increases, vortex breakage is intensified and vortices are not obvious in the flow field. [ABSTRACT FROM AUTHOR]

While two‐dimensional infrared (2D‐IR) spectroscopy is uniquely suitable for monitoring femtosecond (fs) to picosecond (ps) water dynamics around static protein structures, its utility for probing enzyme active‐site dynamics is limited due to the lack of site‐specific 2D‐IR probes. We demonstrate the genetic incorporation of a novel 2D‐IR probe, m‐azido‐L‐tyrosine (N3Y) in the active‐site of DddK, an iron‐dependent enzyme that catalyzes the conversion of dimethylsulfoniopropionate to dimethylsulphide. Our results show that both the oxidation of active‐site iron to FeIII, and the addition of denaturation reagents, result in significant decrease in enzyme activity and active‐site water motion confinement. As tyrosine residues play important roles, including as general acids and bases, and electron transfer agents in many key enzymes, the genetically encoded 2D‐IR probe N3Y should be broadly applicable to investigate how the enzyme active‐site motions at the fs–ps time scale direct reaction pathways to facilitating specific chemical reactions. [ABSTRACT FROM AUTHOR]

Gas leakage from the dipleg of a cyclone separator usually exists due to the the inlet and dipleg output being in a common space. To gain further insight into the pressure characteristics produced by such gas leakage, the pressure drops and instantaneous pressures in a cyclone separator were measured by a U‐tube and dynamic pressure sensors, respectively, under the conditions of different inlet velocities and gas leakage rates. The results showed that the pressure drop linearly decreased with increased gas leakage rate. And the instantaneous pressure fluctuation amplitudes of some regions were greatly affected by gas leakage variations. Instantaneous pressure data were processed in terms of SD, which revealed that the oscillation of the vortex core caused the pressure fluctuations. When the pressure of the upward gas leakage was equal to that of the axial wall surface, the end of the vortex core attached to the lateral wall and formed the larger pressure fluctuation. A power spectral density analysis was carried out for pressure time‐series data, and then the swing frequency (180 Hz) of the vortex core end was detected on the cyclone separator wall surface in the cone lower region (tapping 4). As a consequence, gas leakage could lead to separated particles being re‐entrained, which might heavily deteriorate separation performance of the cyclone separator. [ABSTRACT FROM AUTHOR]

Electrochemical sensors are essential for point‐of‐care testing (POCT) and wearable sensing devices. Establishing an efficient electron transfer route between redox enzymes and electrodes is key for converting enzyme‐catalyzed reactions into electrochemical signals, and for the development of robust, sensitive, and selective biosensors. We demonstrate that the site‐specific incorporation of a novel synthetic amino acid (2‐amino‐3‐(4‐mercaptophenyl)propanoic acid) into redox enzymes, followed by an S‐click reaction to wire the enzyme to the electrode, facilitates electron transfer. The fabricated biosensor demonstrated real‐time and selective monitoring of tryptophan (Trp) in blood and sweat samples, with a linear range of 0.02–0.8 mm. Further developments along this route may result in dramatic expansion of portable electrochemical sensors for diverse health‐determination molecules. [ABSTRACT FROM AUTHOR]

Advances in RNA research and RNA nanotechnology depend on the ability to manipulate and probe RNA with high precision through chemical approaches, both in vitro and in mammalian cells. However, covalent RNA labeling methods with scope and versatility comparable to those of current protein labeling strategies are underdeveloped. A method is reported for the site- and sequence-specific covalent labeling of RNAs in mammalian cells by using tRNAIle2-agmatidine synthetase (Tias) and click chemistry. The crystal structure of Tias in complex with an azide-bearing agmatine analogue was solved to unravel the structural basis for Tias/substrate recognition. The unique RNA sequence specificity and plastic Tias/substrate recognition enable the site-specific transfer of azide/alkyne groups to an RNA molecule of interest in vitro and in mammalian cells. Subsequent click chemistry reactions facilitate the versatile labeling, functionalization, and visualization of target RNA. [ABSTRACT FROM AUTHOR]

Heme proteins are among the most abundant and important metalloproteins, exerting diverse biological functions including oxygen transport, small molecule sensing, selective , nitrite reduction, and electron transfer. Rational heme protein designs focus on the modification of the heme-binding active site and the heme group, protein hybridization and domain swapping, and de novo design. These strategies not only provide us with unique advantages for illustrating the structure-property-reactivity-function (SPRF) relationship of heme proteins in nature but also endow us with the ability to create novel biocatalysts and biosensors. [ABSTRACT FROM AUTHOR]

The article discusses the expansion of photoclick chemistry's genetic code in Arabidopsis thaliana and Escherichia coli mammalian cells. It states that significant problems in plant chemical biology could be addressed by expanding the genetic code as well as introducing photoclick chemistry to plants. It mentions the incorporation of AcrK into proteins in mammalian cells, bacterial cells, and plants, and the use of AcrK to direct rapid fluorescent labeling and chemical probes' litigation.

Effiziente Mehrelektronen ‐ Redoxprozesse werden von Galactose ‐ Oxidase, Cystein ‐ Dioxygenase, Sulfit ‐ Reduktase und Cytochrom ‐ c ‐ Nitrit ‐ Reduktase vermittelt. Eine posttranslational eingeführte Tyrosin ‐ Cystein(Tyr ‐ Cys) ‐ Verknüpfung in ihren aktiven Zentren ist entscheidend für die Funktion. [ABSTRACT FROM AUTHOR]

The article examines a paper on the solubility of oxygen in various alkanolamine-water solutions at low partial pressure. It discusses a proposed equation for determining the solubility of oxygen in deionized water. It also describes the impact of the salinity of the solution on the solubility of oxygen.

Inteins have been widely exploited for the purification of tagless proteins. Among them, pH‐inducible C‐terminal‐cleavage inteins enable the preparation of proteins and peptides with an authentic N‐terminus. However, a severe premature cleavage around neutral pH has limited the application of these inteins, especially when used in recombinant hosts such as Escherichia coli. By targeting the microenvironment of the two key histidine residues H429 and H439, we engineered Mtu ΔI‐CM intein to markedly reduce its premature cleavage. Kinetic analyses suggested that although the variants retained the pH dependence, they indeed cleaved slower, especially at pH 7.6. These variants resulted in higher yields for two model polypeptides than the original Mtu ΔI‐CM intein, when used in conjunction with a cleavable self‐assembling tag. This work suggests that more controllable pH‐inducible inteins can be obtained by manipulating the residues in the self‐cleavage sites and provide better performance for tag‐based protein preparation strategies. [ABSTRACT FROM AUTHOR]

The instability characteristics of gas swirling flow in a cyclone were investigated experimentally by measuring the instantaneous tangential velocity with the hot‐wire anemometry. The results showed that the instantaneous tangential velocity fluctuated continuously with time at both low and high frequencies. Further analysis of measured data regarding time and frequency domain by probability density and spectral methods revealed that the velocity fluctuation was affected not only by the turbulence flow itself but also by gas swirling flow instability. Also, the distributions of dominant frequency and amplitude indicated that low‐frequency velocity fluctuation caused by the instability had the transfer behavior and attenuation character, which could be characterized by the dominant frequency that varied little along the radial position and decreased gradually along the axial direction, while the amplitude increased significantly with decreased radial position. Due to the gas swirling instability, the turbulence intensity and the fine particle diffusion were enhanced, which would degrade the separation efficiency of cyclone. [ABSTRACT FROM AUTHOR]