Cloning, purification, crystallization and preliminary X-ray studies of flagellar hook scaffolding protein FlgD from Pseudomonas aeruginosa PAO1

In order to better elucidate the functions of FlgD in flagellar hook biosynthesis, the three-dimensional structure of FlgD is being determined by X-­ray crystallo­graphy. Here, the expression, purification, crystallization and preliminary crystallographic analysis of FlgD from P. aeruginosa are reported

Structural basis for CD97 recognition of the decay-accelerating factor CD55 suggests mechanosensitive activation of adhesion GPCRs

10.1016/j.jbc.2021.100776Journal of Biological Chemistry29656

A Novel Tri-Coordination Zinc Complex Functionalized Silicotungstate with ROS Catalytic Ability and Anti-Tumor Cells Activity

Reactive oxygen species (ROS) can be used as an effective method to treat tumors. Artificial oxidase has received increasing attention as a catalyst for ROS generation in fields ranging from bioinorganic chemistry to pharmaceutical chemistry. In this study, an artificial oxidase based on a binuclear zinc complex and Keggin-type silicotungstate [Zn2(4,4′-bpy)(Phen)2][SiW12O40] (ZSW) (4,4′-bpy = 4,4′-bipyridine; Phen = 1,10-phenanthroline) was synthesized and structurally featured in terms of its X-ray photoelectron spectrum (XPS), bond valence sum (Σs) calculation, IR spectra, and single-crystal X-ray diffraction (SXRD). ZSW is an ionic compound in which the cation is a binuclear zinc complex [Zn2(4,4′-bpy)(Phen)2]4+ and the anion is a α-Keggin-type silicotungstate [SiW12O40]4– cluster. Notably, the Zn ions in the [Zn2(4,4′-bpy)(Phen)2] exist in tri-coordination, which was first obtained in polyoxometalate (POM) chemistry. It was also demonstrated that ZSW is capable of efficiently catalyzing the production of ROS, which, according to the computational calculations, may be due to the synergistic action of zinc complexes and POM building blocks. Furthermore, ZSW exhibited inhibition ability toward ROS-sensitive tumor cells, such as PC12 cells

A Novel Tri-Coordination Zinc Complex Functionalized Silicotungstate with ROS Catalytic Ability and Anti-Tumor Cells Activity

Reactive oxygen species (ROS) can be used as an effective method to treat tumors. Artificial oxidase has received increasing attention as a catalyst for ROS generation in fields ranging from bioinorganic chemistry to pharmaceutical chemistry. In this study, an artificial oxidase based on a binuclear zinc complex and Keggin-type silicotungstate [Zn2(4,4′-bpy)(Phen)2][SiW12O40] (ZSW) (4,4′-bpy = 4,4′-bipyridine; Phen = 1,10-phenanthroline) was synthesized and structurally featured in terms of its X-ray photoelectron spectrum (XPS), bond valence sum (Σs) calculation, IR spectra, and single-crystal X-ray diffraction (SXRD). ZSW is an ionic compound in which the cation is a binuclear zinc complex [Zn2(4,4′-bpy)(Phen)2]4+ and the anion is a α-Keggin-type silicotungstate [SiW12O40]4– cluster. Notably, the Zn ions in the [Zn2(4,4′-bpy)(Phen)2] exist in tri-coordination, which was first obtained in polyoxometalate (POM) chemistry. It was also demonstrated that ZSW is capable of efficiently catalyzing the production of ROS, which, according to the computational calculations, may be due to the synergistic action of zinc complexes and POM building blocks. Furthermore, ZSW exhibited inhibition ability toward ROS-sensitive tumor cells, such as PC12 cells

An Adaptive Identification Method for Potential Landslide Hazards Based on Multisource Data

The effectiveness of landslide disaster prevention depends largely on the quality of early identification of potential hazards, and how to comprehensively, deeply, and accurately identify such hazards has become a major difficulty in landslide disaster management. Existing deep learning methods for potential landslide hazard identification often use fixed-size window modeling and ignore the different window sizes required by landslides of different scales. To address this problem, we propose an adaptive identification method for potential landslide hazards based on multisource data. Taking Yongping County, China, as the study area, we create a multisource factor dataset based on the landslide disaster background in terms of topography, geology, human activities, hydrology, and vegetation as the sample for the identification model after processing. Moreover, we combine differential interferometric synthetic aperture radar (D-InSAR) and multitemporal InSAR (MT-InSAR) to process the surface deformation of the study area, and we measure the deformation richness based on the average of the pixel deformation difference within the current window of a pixel point in the image. Therefore, convolutional neural networks (CNNs) with different window sizes are adaptively selected. The results show that the precision of adaptive identification of potential landslide hazards in the study area is 85.30%, the recall is 83.03%, and the F1 score is 84.15%. The recognition rate for potential hazards reaches 80%, which is better than the fixed-window modeling result and proves the effectiveness of the proposed method. This method can help to improve intelligent identification systems for potential landslide hazards, and also contribute to the identification of other potential geological hazards, such as mudslides and collapses

Structure-based antigenic epitope and PEGylation improve the efficacy of staphylokinase

Abstract Staphylokinase (Sak) holds promise for use in thrombolytic therapy for acute myocardial infarction. However, its immunogenicity is a major disadvantage under clinical conditions. PEGylation has become a sophisticated method to decrease that immunogenicity. In this report, according predicted epitope from the active center, five residues, including Gly79, Leu82, Lys84, Ala97, and Arg104 have been mutant as cysteine for mono PEGylation, respectively. According to the relative immunogenicity of Sak or its PEGylation derivatives, the amount of specific anti-Sak IgG antibodies elicited by PEGylation proteins, including C79G, C82L, C84K, C97A, and C104R in BALB/c mice decreased by approximately 15–75% each. PEGylated Sak derivatives showed a decrease of up to 75% in the immune reactivity in PEG-Sak-C104R. Thrombelastography experiments showed that two PEG-conjugated derivatives, PEG-Sak-C97A (Ly30, 68.14 ± 2.51%) and PEG-Sak-C104R (Ly30, 66.49 ± 5.97%), the LY30 of PEG-Sak-C97A, and PEG-Sak-C104R produced values very similar to those of wild-type Sak. The fibrin plate assays showed the bioactivity of PEG-Sak-C104R to exhibit the most activity approximately as much as urokinase (diameter of halo pattern, 18.6 ± 1.06 mm) and tPA (diameter of halo pattern, 17.2 ± 0.49 mm). The Sak PEGylation derivative PEG-Sak-C104R was also selected for further in vivo activity experimentation. The thrombolytic ability of PEG-Sak-C104R is a little lower than wild-type Sak, whereas, this PEGylated protein retained high activity suitable for thrombolytic therapy. Collectively, with the in vivo and in vitro experiments, the present study suggests that site mutant PEGylation, PEG-Sak-C104R, is a suitable type of PEGylation for clinical applications. Further optimization would help maintain the bioactivity and decrease the immunogenicity of staphylokinase