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Novel calix[4]pyrrole bearing vic-dioxime ligand (LH2) of the general formula, R1R2C2N2O2H2 (where, R1 = C6H5- and R2 = C39H50N5-) has been synthesized by the reaction of anti-chlorophenylglyoxime with 3-aminophenylcalix[4]pyrrole at room temperature. The mononuclear Cu(II), Ni(II) and Co(II)complexes of this vic-dioxime ligand were prepared and their structures were confirmed by elemental analysis, FT-IR, TGA and magnetic susceptibility measurements; the HMBC, DEPT, 1H and 13C NMR spectra of the LH2 ligand were also reported. The electrochemical property of the complexes was investigated in DMSO by cyclic voltammetry at 200 mV s−1 scan rate. The cyclic voltammetric measurements clearly indicated that Co(LH)2·2H2O complex differs from the Ni(LH)2 and Cu(LH)2 complexes upon the exhibition of quasi-reversible one-electron transfer reduction process in the negative region instead of an irreversible process. 相似文献
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Sümbül AT Akkız H Bayram S Bekar A Akgöllü E Sandıkçı M 《Molecular biology reports》2012,39(2):1639-1647
The tumor suppressor p53 gene plays a crucial role in preventing carcinogenesis through its ability to induce cell cycle arrest
and apoptosis following DNA damage and oncogene activation. A guanine (G)/cytosine (C) common single nucleotide polymorphism
(SNP) at second position of codon 72 in exon 4 of p53 gene determines a arginine (Arg) to proline (Pro) (Arg72Pro) aminoacidic
substitution within the proline-rich domain of p53 protein. Arg72 and Pro72 allele are different from a biochemical and biological
point of view and many reports suggest that they can modulate individual cancer susceptibility. To determine the association
of the p53 Arg72Pro polymorphism with the risk of hepatocellular carcinoma (HCC) development in a Turkish population, a hospital-based
case–control study was designed consisting of 119 subjects with HCC and 119 cancer-free control subjects matched for age,
gender, smoking and alcohol status. The genotype frequency of the p53 Arg72Pro polymorphism was determined by using a polymerase
chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Our data shows that the Pro/Pro genotype of the
p53 Arg72Pro polymorphism is associated with increased risk of HCC development in this Turkish population (OR = 3.20, 95%
CI: 1.24–8.22, P = 0.02). Furthermore, according to stratified analysis, a significant association was observed between the homozygote Pro/Pro
genotype and HCC risk in the subgroups of male gender (OR = 3.01, 95% CI: 1.14–7.97, P = 0.03) and patients with hepatitis B virus (HBV)-related HCC (OR = 4.04, 95% CI: 1.46–11.15, P = 0.007). Because our results suggest for the first time that the Pro/Pro homozygote of p53 Arg72Pro polymorphism may be
a genetic susceptibility factor for HCC (especially in the male gender and HBV-infected patients) in the Turkish population,
further independent studies are required to validate our findings in a larger series, as well as in patients of different
ethnic origins. 相似文献
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Predicting the impact of mutations on the specific activity of Bacillus thermocatenulatus lipase using a combined approach of docking and molecular dynamics
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Onur Yukselen Emel Timucin Ugur Sezerman 《Journal of molecular recognition : JMR》2016,29(10):466-475
Lipases are important biocatalysts owing to their ability to catalyze diverse reactions with exceptional substrate specificities. A combined docking and molecular dynamics (MD) approach was applied to study the chain‐length selectivity of Bacillus thermocatenulatus lipase (BTL2) towards its natural substrates (triacylglycerols). A scoring function including electrostatic, van der Waals (vdW) and desolvation energies along with conformational entropy was developed to predict the impact of mutation. The native BTL2 and its 6 mutants (F17A, V175A, V175F, D176F, T178V and I320F) were experimentally analyzed to determine their specific activities towards tributyrin (C4) or tricaprylin (C8), which were used to test our approach. Our scoring methodology predicted the chain‐length selectivity of BTL2 with 85.7% (6/7) accuracy with a positive correlation between the calculated scores and the experimental activity values (r = 0.82, p = 0.0004). Additionally, the impact of mutation on activity was predicted with 75% (9/12) accuracy. The described study represents a fast and reliable approach to accurately predict the effect of mutations on the activity and selectivity of lipases and also of other enzymes. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Structure-functional characterization of vitamin D receptor (VDR) requires identification of structurally distinct areas of VDR-ligand-binding domain (VDR-LBD) important for biological properties of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3). We hypothesized that covalent attachment of the ligand into VDR-LBD might alter ‘surface structure’ of that area influencing biological activity of the ligand. We compared anti-proliferative activity of three affinity alkylating derivatives of 1,25(OH)2D3 containing an alkylating probe at 1,3 and 11 positions. These compounds possessed high-affinity binding for VDR; and affinity labeled VDR-LBD. But, only the analog with probe at 3-position significantly altered growth in keratinocytes, compared with 1,25(OH)2D3. Molecular models of these analogs, docked inside VDR-LBD tentatively identified Ser237 (helix-3: 1,25(OH)2D3-1-BE), Cys288 (β-hairpin region: 1,25(OH)2D3-3-BE,) and Tyr295 (helix-6: 1,25(OH)2D3-11-BE,) as amino acids that are potentially modified by these reagents. Therefore, we conclude that the β-hairpin region (modified by 1,25(OH)2D3-3-BE) is most important for growth inhibition by 1,25(OH)2D3, while helices 3 and 6 are less important for such activity. 相似文献