31 research outputs found

    Homometallic Silver(I) Complexes of a Heterotopic NHC-Bridged Bis-Bipyridine Ligand

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    By varying the metal to ligand ratio, stepwise formation of a series of homonuclear silverĀ­(I) complexes of a carbene-bridged bis-bipyridine ligand (L) was achieved. In the mononuclear 1:2 complex [AgL2]Br (1) only the carbene carbon is involved in the metal coordination, while both of the 2,2′-bipyridine (bpy) arms are free. When the amount of silverĀ­(I) ion was increased, isomorphous 2:2 dinuclear complexes with different counteranions, [Ag2L2]Ā­X2 (X = Br– (2a), PF6– (2b), BPh4– (2c)), were synthesized from the ligand LX, in which the carbene carbon and one of the bpy units participate in the coordination with silverĀ­(I) ions. Further addition of AgI salt afforded the one-dimensional coordination polymer {[Ag3L2]Ā­(PF6)3Ā·4CH3CN}n (3), wherein the hanging bipyridine units also coordinate with AgI and thus all the coordination sites of the ligand are employed. The results reveal the preference of AgI ion for the carbene carbon donor rather than the bpy units. The synthesis, structures, and interconversion of the complexes and the counteranion effects on the structures are reported, and the luminescent properties of the ligand LX and the silver complexes have also been studied

    Tetraureas versus Triureas in Sulfate Binding

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    By mimicking the scaffolds of oligopyridine-based ligands, triurea and tetraurea receptors have been developed for sulfate binding. The triureas (L1, L2) show stronger binding of sulfate than tetraureas (L3, L4) in DMSO because of their better conformational complementarity with sulfate, while the tetraureas display better ā€œwater toleranceā€ benefiting from the chelate effect and hydrophobic effect

    Tetraureas versus Triureas in Sulfate Binding

    No full text
    By mimicking the scaffolds of oligopyridine-based ligands, triurea and tetraurea receptors have been developed for sulfate binding. The triureas (L1, L2) show stronger binding of sulfate than tetraureas (L3, L4) in DMSO because of their better conformational complementarity with sulfate, while the tetraureas display better ā€œwater toleranceā€ benefiting from the chelate effect and hydrophobic effect

    Homometallic Silver(I) Complexes of a Heterotopic NHC-Bridged Bis-Bipyridine Ligand

    No full text
    By varying the metal to ligand ratio, stepwise formation of a series of homonuclear silverĀ­(I) complexes of a carbene-bridged bis-bipyridine ligand (L) was achieved. In the mononuclear 1:2 complex [AgL<sub>2</sub>]Br (<b>1</b>) only the carbene carbon is involved in the metal coordination, while both of the 2,2′-bipyridine (bpy) arms are free. When the amount of silverĀ­(I) ion was increased, isomorphous 2:2 dinuclear complexes with different counteranions, [Ag<sub>2</sub>L<sub>2</sub>]Ā­X<sub>2</sub> (X = Br<sup>–</sup> (<b>2a</b>), PF<sub>6</sub><sup>–</sup> (<b>2b</b>), BPh<sub>4</sub><sup>–</sup> (<b>2c</b>)), were synthesized from the ligand LX, in which the carbene carbon and one of the bpy units participate in the coordination with silverĀ­(I) ions. Further addition of Ag<sup>I</sup> salt afforded the one-dimensional coordination polymer {[Ag<sub>3</sub>L<sub>2</sub>]Ā­(PF<sub>6</sub>)<sub>3</sub>Ā·4CH<sub>3</sub>CN}<sub><i>n</i></sub> (<b>3</b>), wherein the hanging bipyridine units also coordinate with Ag<sup>I</sup> and thus all the coordination sites of the ligand are employed. The results reveal the preference of Ag<sup>I</sup> ion for the carbene carbon donor rather than the bpy units. The synthesis, structures, and interconversion of the complexes and the counteranion effects on the structures are reported, and the luminescent properties of the ligand LX and the silver complexes have also been studied

    Chloride Coordination by Oligoureas: From Mononuclear Crescents to Dinuclear Foldamers

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    A series of acyclic oligourea receptors which closely resemble the scaffolds and coordination behavior of oligopyridines have been synthesized. Assembly of the receptors with chloride ions afforded mononuclear anion complexes or dinuclear foldamers depending on the number of the urea groups

    Table2_Potential effective diagnostic biomarker in patients with primary and metastatic small intestinal neuroendocrine tumors.XLSX

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    Background: Small intestinal neuroendocrine tumors (SI-NETs) are the most common malignant tumors of the small intestine, with many patients presenting with metastases and their incidence increasing. We aimed to find effective diagnostic biomarkers for patients with primary and metastatic SI-NETs that could be applied for clinical diagnosis.Methods: We downloaded GSE65286 (training set) and GSE98894 (test set) from the GEO database and performed differential gene expression analysis to obtain differentially expressed genes (DEGs) and differentially expressed long non-coding RNAs (DElncRNAs). The functions and pathways involved in these genes were further explored by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. In addition, a global regulatory network involving dysregulated genes in SI-NETs was constructed based on RNAInter and TRRUST v2 databases, and the diagnostic power of hub genes was identified by receiver operating characteristic curve (ROC).Results: A total of 2,969 DEGs and DElncRNAs were obtained in the training set. Enrichment analysis revealed that biological processes (BPs) and KEGG pathways were mainly associated with cancer. Based on gene set enrichment analysis (GSEA), we obtained five BPs (cytokinesis, iron ion homeostasis, mucopolysaccharide metabolic process, platelet degranulation and triglyceride metabolic process) and one KEGG pathway (ppar signaling pathway). In addition, the core set of dysregulated genes obtained included MYL9, ITGV8, FGF2, FZD7, and FLNC. The hub genes were upregulated in patients with primary SI-NETs compared to patients with metastatic SI-NETs, which is consistent with the training set. Significantly, the results of ROC analysis showed that the diagnostic power of the hub genes was strong in both the training and test sets.Conclusion: In summary, we constructed a global regulatory network in SI-NETs. In addition, we obtained the hub genes including MYL9, ITGV8, FGF2, FZD7, and FLNC, which may be useful for the diagnosis of patients with primary and metastatic SI-NETs.</p

    Insight into the Binding Properties of MEKK3 PB1 to MEK5 PB1 from Its Solution Structure<sup>†</sup><sup>,</sup><sup>—</sup>

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    MEKK3 is a mitogen-activated protein kinase kinase kinase that participates in various signaling pathways. One of its functions is to activate the ERK5 signal pathway by phosphorylating and activating MEK5. MEKK3 and MEK5 each harbors a PB1 domain in the N-terminus, and they form a heterodimer via PB1āˆ’PB1 domain interaction that was reported to be indispensable to the activation of MEK5. Using NMR spectroscopy, we show here that a prolyl isomerization of the Gln38āˆ’Pro39 bond is present in MEKK3 PB1, which is the first case of structural heterogeneity within PB1 domains. We have solved the solution structures of both isomers and found a major difference between them in the Pro39 region. Residues Gly37āˆ’Leu40 form a type VIb β-turn in the cis conformation, whereas no obvious character of β-turn was observed in the trans conformation. Backbone dynamics studies have unraveled internal motions in the β3/β4-turn on a microsecondāˆ’millisecond time scale. Further investigation of its binding properties with MEK5 PB1 has demonstrated that MEKK3 PB1 binds MEK5 PB1 tightly with a Kd of about 10-8 M. Mutagenesis analysis revealed that residues in the basic cluster of MEKK3 PB1 contributes differently to the PB1āˆ’PB1 interaction. Residues Lys 7 and Arg 5 play important roles in the interaction with MEK5 PB1. Taken together, this study provides new insights into structural details of MEKK3 PB1 and its binding properties with MEK5 PB1

    DataSheet1_Potential effective diagnostic biomarker in patients with primary and metastatic small intestinal neuroendocrine tumors.ZIP

    No full text
    Background: Small intestinal neuroendocrine tumors (SI-NETs) are the most common malignant tumors of the small intestine, with many patients presenting with metastases and their incidence increasing. We aimed to find effective diagnostic biomarkers for patients with primary and metastatic SI-NETs that could be applied for clinical diagnosis.Methods: We downloaded GSE65286 (training set) and GSE98894 (test set) from the GEO database and performed differential gene expression analysis to obtain differentially expressed genes (DEGs) and differentially expressed long non-coding RNAs (DElncRNAs). The functions and pathways involved in these genes were further explored by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. In addition, a global regulatory network involving dysregulated genes in SI-NETs was constructed based on RNAInter and TRRUST v2 databases, and the diagnostic power of hub genes was identified by receiver operating characteristic curve (ROC).Results: A total of 2,969 DEGs and DElncRNAs were obtained in the training set. Enrichment analysis revealed that biological processes (BPs) and KEGG pathways were mainly associated with cancer. Based on gene set enrichment analysis (GSEA), we obtained five BPs (cytokinesis, iron ion homeostasis, mucopolysaccharide metabolic process, platelet degranulation and triglyceride metabolic process) and one KEGG pathway (ppar signaling pathway). In addition, the core set of dysregulated genes obtained included MYL9, ITGV8, FGF2, FZD7, and FLNC. The hub genes were upregulated in patients with primary SI-NETs compared to patients with metastatic SI-NETs, which is consistent with the training set. Significantly, the results of ROC analysis showed that the diagnostic power of the hub genes was strong in both the training and test sets.Conclusion: In summary, we constructed a global regulatory network in SI-NETs. In addition, we obtained the hub genes including MYL9, ITGV8, FGF2, FZD7, and FLNC, which may be useful for the diagnosis of patients with primary and metastatic SI-NETs.</p
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