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1.
A R Safa M Agresti I Tamai N D Mehta S Vahabi 《Biochemical and biophysical research communications》1990,166(1):259-266
Much evidence suggests that P-glycoprotein (P-gp) confers multidrug-resistance (MDR) in tumor cells by energy-dependent efflux of hydrophobic cytotoxic agents. In this study, we have used the alpha 1-adrenergic photoaffinity probe, [125I]arylazidoprazosin ([125I]AAP), and identified P-gp as a specific acceptor for prazosin. Drugs to which MDR cells are resistant, including vincristine, vinblastine, doxorubicin, actinomycin D and colchicine as well as agents reversing MDR, including verapamil, nicardipine, prenylamine, diltiazem, trifluoperazine, dibucaine, reserpine, monensin, and progesterone, differentially reduced [125I]AAP photolabeling of P-gp. We also analyzed the influence of alpha 2-adrenergic drugs and dopaminergic drugs on [125I]AAP photolabeling of P-gp. Limited proteolysis of [125I]AAP photolabeled P-gp with Staphylococcus aureus V8 protease revealed that prazosin binds to a single 8 kDa fragment of P-gp. 相似文献
2.
Oddo S Caccamo A Cheng D Jouleh B Torp R LaFerla FM 《Journal of neurochemistry》2007,102(4):1053-1063
The two hallmark pathologies of Alzheimer's disease (AD) are amyloid plaques, composed of the small amyloid-beta (Abeta) peptide, and neurofibrillary tangles, comprised aggregates of the microtubule binding protein, tau. The molecular linkage between these two lesions, however, remains unknown. Based on human and mouse studies, it is clear that the development of Abeta pathology can trigger tau pathology, either directly or indirectly. However, it remains to be established if the interaction between Abeta and tau is bidirectional and whether the modulation of tau will influence Abeta pathology. To address this question, we used the 3xTg-AD mouse model, which is characterized by the age-dependent buildup of both plaques and tangles. Here we show that genetically augmenting tau levels and hyperphosphorylation in the 3xTg-AD mice has no effect on the onset and progression of Abeta pathology. These data suggest that the link between Abeta and tau is predominantly if not exclusively unidirectional, which is consistent with the Abeta cascade hypothesis and may explain why tauopathy-only disorders are devoid of any Abeta pathology. 相似文献
3.
Bahareh Honarparvar Sachin A Pawar Cláudio Nahum Alves Jer?nimo Lameira Glenn EM Maguire José Rogério A Silva Thavendran Govender Hendrik G Kruger 《Journal of biomedical science》2015,22(1)
Background
Novel pentacycloundecane (PCU)-lactone-CO-EAIS peptide inhibitors were designed, synthesized, and evaluated against wild-type C-South African (C-SA) HIV-1 protease. Three compounds are reported herein, two of which displayed IC50 values of less than 1.00 μM. A comparative MM-PB(GB)SA binding free energy of solvation values of PCU-lactam and lactone models and their enantiomers as well as the PCU-lactam-NH-EAIS and lactone-CO-EAIS peptide inhibitors and their corresponding diastereomers complexed with South African HIV protease (C-SA) was performed. This will enable us to rationalize the considerable difference between inhibitory concentration (IC50) of PCU-lactam-NH-EAIS and PCU-lactone-CO-EAIS peptides.Results
The PCU-lactam model exhibited more negative calculated binding free energies of solvation than the PCU-lactone model. The same trend was observed for the PCU-peptide inhibitors, which correspond to the experimental activities for the PCU-lactam-NH-EAIS peptide (IC50 = 0.076 μM) and the PCU-lactone-CO-EAIS peptide inhibitors (IC50 = 0.850 μM). Furthermore, a density functional theory (DFT) study on the natural atomic charges of the nitrogen and oxygen atoms of the three PCU-lactam, PCU-lactim and PCU-lactone models were performed using natural bond orbital (NBO) analysis. Electrostatic potential maps were also used to visualize the electron density around electron-rich regions. The asymmetry parameter (η) and quadrupole coupling constant (χ) values of the nitrogen and oxygen nuclei of the model compounds were calculated at the same level of theory. Electronic molecular properties including polarizability and electric dipole moments were also calculated and compared. The Gibbs theoretical free solvation energies of solvation (∆Gsolv) were also considered.Conclusions
A general trend is observed that the lactam species appears to have a larger negative charge distribution around the heteroatoms, larger quadrupole constant, dipole moment and better solvation energy, in comparison to the PCU-lactone model. It can be argued that these characteristics will ensure better eletronic interaction between the lactam and the receptor, corresponding to the observed HIV protease activities in terms of experimental IC50 data.Electronic supplementary material
The online version of this article (doi:10.1186/s12929-015-0115-5) contains supplementary material, which is available to authorized users. 相似文献4.
Bahmani Bahareh Amini-bayat Zahra Ranjbar Mohammad Mehdi Bakhtiari Nahid Zarnani Amir-Hassan 《International journal of peptide research and therapeutics》2021,27(1):365-378
International Journal of Peptide Research and Therapeutics - Cervical cancer is the second most common leading cause of women's death due to cancer worldwide, about 528,000 patients’... 相似文献
5.
Leila Sadeghi Khosro Khajeh Nasrin Mollania Bahareh Dabirmanesh Bijan Ranjbar 《Molecular biotechnology》2013,53(3):270-277
It is the common feature of α-amylases that calcium ion is required for their structural integrity and thermal stability. All amylases have at least one Ca2+ per molecule; therefore amino acids involved in calcium binding are specific and conserved. In this study, sequence analysis revealed the presence of EF-hand-like motif in calcium-binding loop of Bacillus megaterium WHO (BMW)-amylase that was previously isolated from BMW. The EF-hand motif and its variants (EF-hand-like motif) are the most common calcium-binding motifs found in a large number of protein families. To investigate the effect of calcium ion on the thermal stability and activity of BMW-amylase, we used site-directed mutagenesis to replace histidine 58 with Asp (D), Ile (I), Tyr (Y), Phe (F), and Arg (R) at the seventh position of EF-hand-like motif. Upon the addition of an extra DX unit to the calcium-binding loop in H58D variant, thermal stability, catalytic activity, and chelating power of the enzyme improved due to higher affinity toward calcium. H58D variant demonstrated calcium independency compared to the wild type and other created mutants. Conformational changes in the presence and absence of Ca2+ were monitored using fluorescence technique. 相似文献
6.
The endophytic fungus Piriformospora indica colonizes the roots of many plant species including Arabidopsis and promotes their performance, biomass, and seed production as well as resistance against biotic and abiotic stress. Imbalances in the symbiotic interaction such as uncontrolled fungal growth result in the loss of benefits for the plants and activation of defense responses against the microbe. We exposed Arabidopsis seedlings to a dense hyphal lawn of P. indica. The seedlings continue to grow, accumulate normal amounts of chlorophyll, and the photosynthetic parameters demonstrate that they perform well. In spite of high fungal doses around the roots, the fungal material inside the roots was not significantly higher when compared with roots that live in a beneficial symbiosis with P. indica. Fifteen defense- and stress-related genes including PR2, PR3, PAL2, and ERF1 are only moderately upregulated in the roots on the fungal lawn, and the seedlings did not accumulate H2O2/radical oxygen species. However, accumulation of anthocyanin in P. indica-exposed seedlings indicates stress symptoms. Furthermore, the jasmonic acid (JA) and jasmonic acid-isoleucine (JA-Ile) levels were increased in the roots, and consequently PDF1.2 and a newly characterized gene for a 2-oxoglurate and Fe2+-dependent oxygenase were upregulated more than 7-fold on the dense fungal lawn, in a JAR1- and EIN3-dependent manner. We conclude that growth of A. thaliana seedlings on high fungal doses of P. indica has little effect on the overall performance of the plants although elevated JA and JA-Ile levels in the roots induce a mild stress or defense response. 相似文献
7.
Bahareh Khodashenas Mehdi Ardjmand Azim Akbarzadeh Khiyavi 《Journal of biomolecular structure & dynamics》2020,38(15):4644-4654
AbstractCommunicated by Ramaswamy H. Sarma 相似文献
8.
Nasri Elahe Shoaei Parisa Vakili Bahareh Mirhendi Hossein Sadeghi Somayeh Hajiahmadi Somayeh Sadeghi Alireza Vaezi Afsane Badali Hamid Fakhim Hamed 《Mycopathologia》2020,185(6):1077-1084
Mycopathologia - Although patients with severe immunodeficiency and hematological malignancies has been considered at highest risk for invasive fungal infection, patients with severe pneumonia due... 相似文献
9.
Zarrati Mitra Raji Lahiji Mahsa Salehi Eisa Yazdani Bahareh Razmpoosh Elham Shokouhi Shoormasti Raheleh Shidfar Farzad 《Probiotics and antimicrobial proteins》2019,11(4):1202-1209
Probiotics and Antimicrobial Proteins - Data on the effects of probiotics on adipokines such as omentin-1, nesfatin-1, and adropin are limited. The aim of this study was to evaluate the effects of... 相似文献
10.
Bahrami G Mohammadi B 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2007,850(1-2):400-404
A new, sensitive and simple high-performance liquid chromatographic method for analysis of topiramate, an antiepileptic agent, using 4-chloro-7-nitrobenzofurazan as pre-column derivatization agent is described. Following liquid-liquid extraction of topiramate and an internal standard (amlodipine) from human serum, derivatization of the drugs was performed by the labeling agent in the presence of dichloromethane, methanol, acetonitrile and borate buffer (0.05 M; pH 10.6). A mixture of sodium phosphate buffer (0.05 M; pH 2.4): methanol (35:65 v/v) was eluted as mobile phase and chromatographic separation was achieved using a Shimpack CLC-C18 (150 x 4.6 mm) column. In this method the limit of quantification of 0.01 microg/mL was obtained and the procedure was validated over the concentration range of 0.01 to 12.8 microg/mL. No interferences were found from commonly co-administrated antiepileptic drugs including phenytoin, phenobarbital carbamazepine, lamotrigine, zonisamide, primidone, gabapentin, vigabatrin, and ethosuximide. The analysis performance was carried-out in terms of specificity, sensitivity, linearity, precision, accuracy and stability and the method was shown to be accurate, with intra-day and inter-day accuracy from -3.4 to 10% and precise, with intra-day and inter-day precision from 1.1 to 18%. 相似文献