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Toumi-Maouche A Maouche B Taïri-Kellou S El-Aoufi S Martín-Martínez M González-Muñiz R Fourmy D Maigret B 《Journal of molecular modeling》2008,14(4):303-314
Pyridopyrimidine-based analogues are among the most highly potent and selective antagonists of cholecystokinin receptor subtype-1
(CCK1R) described to date. To better understand the structural and chemical features responsible for the recognition mechanism,
and to explore the binding pocket of these compounds, we performed automated molecular docking using GOLD2.2 software on some
derivatives with structural diversity, and propose a putative binding conformation for each compound. The docking protocol
was guided by the key role of the Asn333 residue, as revealed by site directed mutagenesis studies. The results suggest two
putative binding modes located in the same pocket. Both are characterized by interaction with the main residues revealed by
experiment, Asn333 and Arg336, and differ in the spatial position of the Boc-Trp moiety of these compounds. Hydrophobic contacts with residues Thr117, Phe107, Ile352 and Ile329 are also in agreement
with experimental data. Despite the poor correlation obtained between the estimated binding energies and the experimental
activity, the proposed models allow us to suggest a plausible explanation of the observed binding data in accordance with
chemical characteristics of the compounds, and also to explain the observed diastereoselectivity of this family of antagonists
towards CCK1R. The most reasonable selected binding conformations could be the starting point for future studies.
Figure Superimposition of the two putative binding conformations revealed by molecular docking for pyridopyrimidine-based CCK1 antagonists 相似文献
73.
Fibronectin (FN) is an extracellular matrix (ECM) protein found soluble in corporal fluids or as an insoluble fibrillar component incorporated in the ECM. This phenomenon implicates structural changes that expose FN binding sites and activate the protein to promote intermolecular interactions with other FN. We have investigated, using fluorescence and circular dichroism spectroscopy, the unfolding process of human fibronectin induced by urea in different ionic strength conditions. At any ionic strength, the equilibrium unfolding data are well described by a four-state equilibrium model N <= => I(1) <= =>I(2) <= => U. Fitting this model to experimental values, we have determined the free energy change for the different steps. We found that the N <= => I(1) transition corresponds to a free energy of 10.5 +/- 0.4 kcal/mol. Comparable values of free energy change are generally associated with a partial unfolding of the type III domain. For the I(1) <= => I(2) transition, the free energy change is 7.6 +/- 0.4 kcal/mol at low ionic strength but is twice as low at high ionic strength. This result is consistent with observations indicating that the complete unfolding of the type III domain from partially unfolded forms necessitates about 5 kcal/mol. The third step, I(2) <= => U, which leads to the complete unfolding of fibronectin, corresponds to a free energy change of 14.4 +/- 0.9 kcal/mol at low ionic strength whereas this energy is again twice as low under high ionic strength conditions. This hierarchical unfolding of fibronectin, as well as the stability of the different intermediates controlled by ionic strength demonstrated here, could be important for the understanding of activation of the matrix assembly. 相似文献
74.
Complement mediates the binding of HIV to erythrocytes 总被引:4,自引:0,他引:4
Horakova E Gasser O Sadallah S Inal JM Bourgeois G Ziekau I Klimkait T Schifferli JA 《Journal of immunology (Baltimore, Md. : 1950)》2004,173(6):4236-4241
A fraction of HIV is associated with erythrocytes even when the virus becomes undetectable in plasma under antiretroviral therapy. The aim of the present work was to further characterize this association in vitro. We developed an in vitro model to study the factors involved in the adherence of HIV-1 to erythrocytes. Radiolabeled HIV-1 (HIV) and preformed HIV-1/anti-HIV immune complexes (HIV-IC) were opsonized in various human sera, purified using sucrose density gradient ultracentrifugation, and incubated with human erythrocytes. We observed that, when opsonized in normal human serum, not only HIV-IC, but also HIV, bound to erythrocytes, although the adherence of HIV was lower than that of HIV-IC. The adherence was abolished when the complement system was blocked, but was maintained in hypogammaglobulinemic sera. Complement-deficient sera indicated that both pathways of complement were important for optimal adherence. No adherence was seen in C1q-deficient serum, and the adherence of HIV was reduced when the alternative pathway was blocked using anti-factor D Abs. The adherence could be inhibited by an mAb against complement receptor 1. At supraphysiological concentrations, purified C1q mediated the binding of a small fraction of HIV and HIV-IC to erythrocytes. In conclusion, HIV-IC bound to erythrocytes as other types of IC do when exposed to complement. Of particular interest was that HIV alone bound also to erythrocytes in a complement/complement receptor 1-dependent manner. Thus, erythrocytes may not only deliver HIV-IC to organs susceptible to infection, but free HIV as well. This may play a crucial role in the progression of the primary infection. 相似文献
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Langerhans cell histiocytosis is a rare disorder characterized by abnormal proliferation of Langerhans cells that can affect various organ systems. The disease usually presents as a unifocal lytic bone lesion and can affect any age group. Less frequently it presents as a disseminated disease with multisystem involvement. Hepatic manifestation in Langerhans cell histiocytosis is relatively rare and usually presents as a part of a disseminated process. We report a case of Langerhans cell histiocytosis involving only the liver in a 9-years-old child. 相似文献
77.
Gene therapy of severe combined immunodeficiencies has been proven to be effective to provide sustained correction of the T cell immunodeficiencies. This has been achieved for 2 forms of SCID, i.e SCID-X1 (γc deficiency) and adenosine deaminase deficiency. Occurrence of gene toxicity generated by integration of first generation retroviral vectors, as observed in the SCID-X1 trials has led to replace these vectors by self inactivated (SIN) retro(or lenti) viruses that may provide equivalent efficacy with a better safety profile. Results of ongoing clinical studies in SCID as well as in other primary immunodeficiencies, such as the Wiskott Aldrich syndrome, will be thus very informative. 相似文献
78.
Anna Marchese Erika Coppo Ramona Barbieri Davide Barreca Salima Chebaibi 《Biofouling》2013,29(6):630-656
AbstractCarvacrol (5-isopropyl-2-methyl phenol) is a natural compound that occurs in the leaves of a number of plants and herbs including wild bergamot, thyme and pepperwort, but which is most abundant in oregano. The aim of this review is to analyse the scientific data from the last five years (2012-2017) on the antimicrobial and anti-biofilm activities of carvacrol, targeting different bacteria and fungi responsible for human infectious diseases. The antimicrobial and anti-biofilm mechanisms of carvacrol and its synergies with antibiotics are illustrated. The potential of carvacrol-loaded anti-infective nanomaterials is underlined. Carvacrol shows excellent antimicrobial and anti-biofilm activities, and is a very interesting bioactive compound against fungi and a wide range of Gram-positive and Gram-negative bacteria, and being active against both planktonic and sessile human pathogens. Moreover, carvacrol lends itself to being combined with nanomaterials, thus providing an opportunity for preventing biofilm-associated infections by new bio-inspired, anti-infective materials. 相似文献
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Jaballah Abir Soltani Ismael Bahia Wael Dandana Azza Hasni Yosra Miled Abdelhedi Ferchichi Salima 《Biochemical genetics》2021,59(6):1558-1581
Biochemical Genetics - Menopausal hormonal changes have been associated with the emergence of the metabolic syndrome (MetS) and its consequences such as type 2 diabetes (T2D) and cardiovascular... 相似文献
80.
Salima Kebbouche-Gana Mohamed Lamine Gana Imen Ferrioune Souad Khemili Nesrine Lenchi Sihem Akmouci-Toumi Nabila Amel Bouanane-Darenfed Nacer-Eddine Djelali 《Extremophiles : life under extreme conditions》2013,17(6):981-993
A bacterial strain E21 was isolated from a sample of water collected in the salt lake located close to Ain Salah, Algeria. The analysis of 16S rRNA gene sequence had indicated that the strain had 93 % sequence similarity with the genus Natrialba sp. strain E21 (GenBank, FR750525.1) and was considered extremely halophilic. Production of biosurfactant by the strain E21 with free and entrapped cells was investigated using soluble starch in the saline conditions. Biosurfactant synthesis was followed by measuring the surface tension and emulsifying index 9 days under optimal conditions (40 °C, pH 7). Some diffusional limitations in alginate and agar beads affected the kinetics of biosurfactant production when compared to that obtained with free cells culture. The minimum values of surface tension were 27 and 30 mN m?1 achieved after 9 days with free and immobilized cells, respectively, while the corresponding maximum E24 values were 65.3 and 62.3 %, respectively. The re-use of bacterial cells along with the limited cell losses provided by the immobilized system might lead to significant reduction of the biosurfactant production cost. 相似文献