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Motivation Metalloenzymes are attractive targets for therapeutic intervention owing to their central roles in various biological processes and pathological situations. The fast-growing body of structural data on metalloenzyme-ligand interactions is facilitating efficient drug discovery targeting metalloenzymes. However, there remains a shortage of specific databases that can provide centralized, interconnected information exclusive to metalloenzyme-ligand associations. Results We created a M etallo e nzyme- L igand A ssociation D atabase (MeLAD), which is designed to provide curated structural data and information exclusive to metalloenzyme-ligand interactions, and more uniquely, present expanded associations that are represented by metal-binding pharmacophores (MBPs), metalloenzyme structural similarity (MeSIM) and ligand chemical similarity (LigSIM). MeLAD currently contains 6086 structurally resolved interactions of 1416 metalloenzymes with 3564 ligands, of which classical metal-binding, non-classical metal-binding, non-metal-binding and metal water-bridging interactions account for 63.0%, 2.3%, 34.4% and 0.3%, respectively. A total of 263 monodentate, 191 bidentate and 15 tridentate MBP chemotypes were included in MeLAD, which are linked to different active site metal ions and coordination modes. 3726 and 52 740 deductive metalloenzyme-ligand associations by MeSIM and LigSIM analyses, respectively, were included in MeLAD. An online server is provided for users to conduct metalloenzyme profiling prediction for small molecules of interest. MeLAD is searchable by multiple criteria, e.g. metalloenzyme name, ligand identifier, functional class, bioinorganic class, metal ion and metal-containing cofactor, which will serve as a valuable, integrative data source to foster metalloenzyme related research, particularly involved in drug discovery targeting metalloenzymes. Availability and implementation MeLAD is accessible at https://melad.ddtmlab.org. Supplementary information Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

In this study, we employed Q Exactive to determine the main differential metabolites of Magnoliae Officinalis Cortex du-ring the "sweating" process. Further, we quantified the color parameters and determined the activities of polyphenol oxidase(PPO), peroxidase(POD), and tyrosinase of Magnoliae Officinalis Cortex during the "sweating" process. Gray correlation analysis was performed for the color, chemical composition, and enzyme activity to reveal the effect of enzymatic reaction on the color of Magnoliae Officinalis Cortex during the "sweating" process. Magnoliae Officinalis Cortex sweating in different manners showed similar metabolite changes. The primary metabolites that changed significantly included amino acids, nucleotides, and sugars, and the secondary metabolites with significant changes were phenols and phenylpropanoids. Despite the different sweating methods, eleven compounds were commonly up-regulated, including L-glutamic acid, acetylarginine, hypoxanthine, and xanthine; six compounds were commonly down-re-gulated, including L-arginine, L-aspartic acid, and phenylalanine. The brightness value(L~*), red-green value(a~*), and yellow-blue value(b~*) of Magnoliae Officinalis Cortex kept decreasing during the "sweating" process. The changes in the activities of PPO and POD during sweating were consistent with those in the color parameter values. The gray correlation analysis demonstrated that the main differential metabolites such as amino acids and phenols were closely related to the color parameters L~*, a~* and b~*; POD was correlated with amino acids and phenols; PPO had strong correlation with phenols. The results indicated that the color change of Magnoliae Officinalis Cortex during "sweating" was closely related to the reactions of enzymes dominated by PPO and POD. The study analyzed the correlations among the main differential metabolites, color parameters, and enzyme activities of Magnoliae Officinalis Cortex in the "sweating" process. It reveals the common law of material changes and ascertains the relationship between color changes and enzymatic reactions of Magnoliae Officinalis Cortex during "sweating". Therefore, this study provides a reference for studying the "sweating" mechanism of Magnoliae Officinalis Cortex and is of great significance to guarantee the quality of Magnoliae Officinalis Cortex.

Magnolia officinalis is a traditional Chinese medicine,with many years of cultivating process, M. officinalis leaves show more differentiation types due to the exchange of seeds from different provenances. "Da Ao"(DA), "Xiao Ao"(XA), "Chuan Hou"(CH),and "Liu Ye"(LY)are the main types of M. officinalis in Sichuan province of China,and there were obvious differences in growth rate,chemical composition,leaf shape and leaf colour. This study selected different types of M. officinalis leaves(DA,XA,LY and CH)from Sichuan to determine their chlorophyll content. Transcriptomic level sequencing of different types of M. officinalis leaf tissues was by high-throughput sequencing analysis and proteomics used an integrated approach involving TMT labelling and LC-MS/MS to quantify the dynamic changes of the whole proteome of M. officinalis. The results showed that CH had the lowest chlorophyll content while DA had the highest chlorophyll content. Furthermore,transcriptome and proteomics results showed that chlorophyll synthesis pathway in DA glutamine-tRNA reductase,urinary porphyrins decarboxylase(UROD),oxygen-dependent protoporphyrin(ODCO),the original-Ⅲ oxidase protoporphyrin oxidase(PPO),magnesium chelating enzyme subunit ChlD,protoporphyrin magnesium Ⅸ monomethyl ester [oxidative] cyclase(MPPMC)were significantly higher than CH,XA and LY,consistent in the results of determination of chlorophyll content(chlorophyll content was highest of 37.56 mg·g~(-1) FW). Some rate-limiting enzymes related to the chlorophyll synthesis,such as ODCO,PPO and MPPMC were tested by Parallel Reaction Monitoring(PRM),and the results showed that the rate-limiting enzyme content in DA was higher than that in other three types. Therefore,based on the differences in leaf color of four types of M. officinalis,the research conducted a preliminary study on the chlorophyll metabolism pathway in leaves of different types of M. officinalis,and explored relevant genes and proteins causing leaf color differences from the molecular level,so as to lay a foundation for studying the differences in growth and development of different types of M. officinalis.

A high-quality X-ray crystal structure reveals the mechanism of compound 1a inhibiting SIRT2 deacetylase and decanoylase. Structure-activity relationship (SAR) analysis of the synthesized derivatives of 1a reveals the high requirements needed for selective inhibitors to bind with the induced hydrophobic pocket and potently inhibit sirtuin 2 deacetylase.

In order to monitor heavy metal pollution in agricultural soils and assess the corresponding health risk in the Yellow River irrigation area, this study applied the Nemero index and the health risk index to evaluate heavy metal pollution in wheat grains and the health risks for residents in the lower reaches of the Yellow River. Four towns in Kaifeng, which are within the lower reaches of the Yellow River, were selected as the study area. The examination of wheat samples revealed that the average contents of Cd, Cr, Pb, Cu, Zn, Ni, and Hg in the wheat grains were 0.034, 0.428, 0.279, 5.363, 29.605, 0.305, and 0.003 mg·kg -1 , respectively. Among the heavy metals, Pb and Zn exceeded the national food hygiene standards. The pollution indices of Pb and Zn in the wheat grains contributed significantly to the comprehensive pollution index, as each was greater than 1 (1.985), although the pollution indices of the other heavy metals were less than 1. The comprehensive pollution index of wheat in each town ranged from 1.116 to 1.847. The health risk indices of non-carcinogenic heavy metals (Pb, Cu, Zn, and Hg) for adults and children were 1.0558 and 0.5450, respectively. The health risk indices of carcinogenic heavy metals (Cd, Cr, and Ni) for adults and children were higher than the maximum acceptable risk level (1×10 -4 ) recommended by the USEPA, which suggests that residents of the study area have a high risk of developing various forms of cancer.

The impact of global warming on the growth and development of natural vegetation is an important concern worldwide. Based on the data from the vegetation normalization index, daytime temperature (T max ), nighttime temperature (T min ), precipitation, and elevation from 1982 to 2015, we examined the day-night warming response of 42 types of natural vegetation in China. The results showed that both the temperature at day and night was significantly increased in the study area, with obvious asymmetry. The night warming was about 1.6 times as high as that at daytime. The T min was more conducive to vegetation growth than the T max . The proportion of vegetation types with positive relationship with T min was greater than the T max , with significant spatial difference. Subtropical vegetation accounted for 85.7% of vegetation with positive correlation with T max . The temperate alpine, mountainous, and desert vegetation responded more positively to T min . The increase of T min was not conducive to the growth and development of vegetation at high altitudes, while that of T max was the opposite. The correlations of vegetation growth with T max and T min were as follows: steppe > meadow > needleleaf forest > desert vegetation > broadleaf forest; meadow > desert vegetation > broadleaf forest > steppe > needleleaf forest.