HIV-1 integrase (HIV-1 IN) is an enzyme produced by the HIV-1 virus that integrates genetic material of the virus into the DNA of infected human cells. HIV-1 IN acts as a key component of the Retroviral Pre-Integration Complex (PIC). Protein dynamics could play an important role during the catalysis of HIV-1 IN; however, this process has not yet been fully elucidated. X-ray free electron laser (XFEL) together with nuclear magnetic resonance (NMR) could provide information regarding the dynamics during this catalysis reaction. Here, we report the non-cryogenic crystal structure of HIV-1 IN catalytic core domain at 2.5 A using microcrystals in XFELs. Compared to the cryogenic structure at 2.1 A using conventional synchrotron crystallography, there was a good agreement between the two structures, except for a catalytic triad formed by Asp64, Asp116, and Glu152 (DDE) and the lens epithelium-derived growth factor binding sites. The helix III region of the 140–153 residues near the active site and the DDE triad show a higher dynamic profile in the non-cryogenic structure, which is comparable to dynamics data obtained from NMR spectroscopy in solution state.
CXCR1 is a G-protein coupled receptor, transducing signals from chemokines, in particular the interleukin-8 (IL8) molecules. This study combines homology modeling and molecular dynamics simulation methods to study the structure of CXCR1-IL8 complex. By using CXCR4-vMIP-II crystallography structure as the homologous template, CXCR1-IL8 complex structure was constructed, and then refined using all-atom molecular dynamics simulations. Through extensive simulations, CXCR1-IL8 binding poses were investigated in detail. Furthermore, the role of the N-terminal of CXCR1 receptor was studied by comparing four complex models differing in the N-terminal sequences. The results indicate that the receptor N-terminal affects the binding of IL8 significantly. With a shorter N-terminal domain, the binding of IL8 to CXCR1 becomes unstable. The homology modeling and simulations also reveal the key receptor-ligand residues involved in the electrostatic interactions known to be vital for complex formation.
Purpose We aimed to uncover the role of METTL3 in stimulating the stemness and progression of breast cancer (BCa) through mediating N6-methyladenosine (m6A) modification on SOX2 mRNA. Methods METTL3 levels in 48 paired BCa and adjacent normal ones were examined. Kaplan-Meier method was introduced for assessing the prognostic value of METTL3 in BCa. Regulatory effects of METTL3 on invasive and migratory abilities in MCF-7 cells were evaluated by Transwell assay. Besides, the protein levels of SOX2 and tumor stem cell markers CD133 and CD44 in MCF-7 cells affected by METTL3 were determined by Western blot. In addition, the potential interaction between METTL3 and SOX2 was ascertained through RIP (RNA-Binding Protein Immunoprecipitation) assay. Moreover, the interaction between IGF2BP2 and SOX2 influenced by METTL3 was verified by RIP assay as well. Results METTL3 was upregulated in BCa tissues, especially in T3-T4 or those accompanied with lymphatic metastasis. BCa patients expressing a high level of METTL3 suffered worse prognosis. Knockdown of METTL3 downregulated protein levels of SOX2, CD133 and CD44 in MCF-7 cells. Moreover, invasive and migratory abilities were attenuated in BCa cells with METTL3 knockdown. Silencing of IGF2BP2 markedly downregulated SOX2. RIP assay confirmed the binding between METTL3 and SOX2 mRNA, and knockdown of METTL3 decreased the enrichment of SOX2 in anti-IGF2BP2. Interestingly, overexpression of SOX2 partially reversed the regulatory effects of downregulated METTL3 on MCF-7 cells. Conclusions METTL3 is upregulated in BCa, and it promotes the stemness and malignant progression of BCa through mediating m6A modification on SOX2 mRNA.
We aimed to uncover the role of METTL3 in stimulating the stemness and progression of breast cancer (BCa) through mediating N6-methyladenosine (m6A) modification on SOX2 mRNA.METTL3 levels in 48 paired BCa and adjacent normal ones were examined. Kaplan-Meier method was introduced for assessing the prognostic value of METTL3 in BCa. Regulatory effects of METTL3 on invasive and migratory abilities in MCF-7 cells were evaluated by Transwell assay. Besides, the protein levels of SOX2 and tumor stem cell markers CD133 and CD44 in MCF-7 cells affected by METTL3 were determined by Western blot. In addition, the potential interaction between METTL3 and SOX2 was ascertained through RIP (RNA-Binding Protein Immunoprecipitation) assay. Moreover, the interaction between IGF2BP2 and SOX2 influenced by METTL3 was verified by RIP assay as well.METTL3 was upregulated in BCa tissues, especially in T3-T4 or those accompanied with lymphatic metastasis. BCa patients expressing a high level of METTL3 suffered worse prognosis. Knockdown of METTL3 downregulated protein levels of SOX2, CD133 and CD44 in MCF-7 cells. Moreover, invasive and migratory abilities were attenuated in BCa cells with METTL3 knockdown. Silencing of IGF2BP2 markedly downregulated SOX2. RIP assay confirmed the binding between METTL3 and SOX2 mRNA, and knockdown of METTL3 decreased the enrichment of SOX2 in anti-IGF2BP2. Interestingly, overexpression of SOX2 partially reversed the regulatory effects of downregulated METTL3 on MCF-7 cells.METTL3 is upregulated in BCa, and it promotes the stemness and malignant progression of BCa through mediating m6A modification on SOX2 mRNA.
High-entropy materials (HEMs) are new-fashioned functional materials in the field of catalysis owing to their large designing space, tunable electronic structure, interesting "cocktail effect", and entropy stabilization effect. Many effective strategies have been developed to design advanced catalysts for various important reactions. Herein, we firstly review effective strategies developed so far for optimizing HEM-based catalysts and the underlying mechanism revealed by both theoretical simulations and experimental aspects. In light of this overview, we subsequently present some perspectives about the development of HEM-based catalysts and provide some serviceable guidelines and/or inspiration for further studying multicomponent catalysts.
Abstract Background: PDZ-binding kinase/T lymphokine-activated killer cell-derived protein kinase (PBK/TOPK) is a potential prognostic indicator for patients with breast cancer. The objective of the present study was to explore the relationship between PBK/TOPK expression and clinicopathological indicators as well as the survival of patients with breast cancer. Methods: Immunohistochemical staining was used to detect the expression of PBK/TOPK in 202 cases of breast cancer tissues. The relationship between PBK/TOPK and clinicopathological parameters was evaluated using Spearman's rank-order correlation. The difference in PBK/TOPK expression among different molecular types was analyzed with the chi square test. Kaplan-Meier analysis was used to create a survival curve and the log rank test was used to analyze the overall survival (OS) and disease-free survival (DFS). Prognostic correlation was assessed using univariate and multivariate Cox regression analyses. Results: Among 202 breast cancer samples, PBK/TOPK was expressed ('+' and '++') in 182 samples (90.1%). In addition, the histological grade, TNM stages, lymph node metastasis, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), and Ki-67 were positively associated with PBK/TOPK expression. With regard to the molecular type, the expression of PBK/TOPK is different. The expression level of PBK/TOPK was negatively correlated with both the OS and DFS of breast cancer patients. The difference in the above results is meaningful (P<0.05). Conclusions: PBK/TOPK is over-expressed in breast cancer and the expression is closely related to the clinicopathological characteristics of the disease. Breast cancer patients with high expression of PBK/TOPK have a poor prognosis. Therefore, health care providers can optimize breast cancer management using this indicator.
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