排序方式: 共有30条查询结果,搜索用时 109 毫秒
1.
Use of an oriented transmembrane protein to probe the assembly of a supported phospholipid bilayer. 总被引:2,自引:1,他引:1 下载免费PDF全文
Planar-supported phospholipid bilayers formed by the adsorption of vesicles are increasingly used in the investigation of lipid-dependent reactions. We have studied the way in which these bilayers are formed with phospholipid vesicles containing the transmembrane protein Tissue Factor (TF). TF complexed with the serine protease, factor VIIa, is the primary initiator of blood coagulation by way of activation of the zymogen factor X. TF has been shown to orient randomly on the inner and outer leaflets of vesicles. We used proteolytic digestion to produce vesicles in which the extracellular domain of TF is located on the inner leaflet. These vesicles show no cofactor activity for factor VIIa as a result of the inability of the extracellular domain of TF to bind VIIa. After freeze/thawing, 50% of the cofactor activity was regained, indicating reorientation of the sequestered, inner leaflet TF. Adsorption of these vesicles to the inner surface of glass microcapillaries results in a continuous phospholipid bilayer. The microcapillaries were perfused with a solution of factors VIIa and X, and the effluent was monitored for factor Xa production, a sensitive measure of the activity of the TF-VIIa complex. For coatings produced with the digested vesicles, minimal TF-VIIa activity was observed, showing that the supported bilayer preserves the orientation of the leaflets in the vesicles, i.e., the outer leaflet of the vesicles forms the outer leaflet of the supported bilayer. 相似文献
2.
J. B. Alexander Ross Paul B. Contino Mark F. Lulka Philip H. Petra 《Journal of Protein Chemistry》1985,4(5):299-304
The first direct evidence for specific metal-binding sites in pure human and pure rabbit sex steroid-binding protein (SBP) is obtained using the luminescent lanthanide terbium. Terbium, a probe for calcium sites in proteins, provided protection of the SBP steroid-binding activity in diluted human serum samples equivalent to that provided by calcium. Pure SBP, first treated with ethylenediaminetetraacetate, was dialyzed against buffer containing TbCl3. After gel filtration to remove nonspecifically bound terbium, the protein was denatured in urea. The amount of protein-bound terbium was determined by luminescence enhancement of the lanthanide using the chelator dipicolinate, yielding four metal-binding sites per mole of dimer protein from both species. 相似文献
3.
David R. Bauman Alan Whitehead Lisa C. Contino Jisong Cui Margarita Garcia-Calvo Xin Gu Nancy Kevin Xiuying Ma Lee-yuh Pai Kashmira Shah Xiaolan Shen Sloan Stribling Hratch J. Zokian Joe Metzger Diane E. Shevell Sherman T. Waddell 《Bioorganic & medicinal chemistry letters》2013,23(12):3650-3653
In an effort to understand the origin of blood-pressure lowering effects observed in recent clinical trials with 11β-HSD1 inhibitors, we examined a set of 11β-HSD1 inhibitors in a series of relevant in vitro and in vivo assays. Select 11β-HSD1 inhibitors reduced blood pressure in our preclinical models but most or all of the blood pressure lowering may be mediated by a 11β-HSD1 independent pathway. 相似文献
4.
Ferorelli S Abate C Pedone MP Colabufo NA Contino M Perrone R Berardi F 《Bioorganic & medicinal chemistry》2011,19(24):7612-7622
Starting from two carbocyclic analogs, a series of 3,3-dimethylpiperidine derivatives was prepared and tested in radioligand binding assays at σ(1) and σ(2) receptors, and at Δ(8)-Δ(7) sterol isomerase (SI) site. The novel compounds mostly bear heterocyclic rings or bicyclic nucleus of differing lipophilicities. Compounds 18a and 19a,b demonstrated the highest σ(1) affinity (K(i)=0.14-0.38 nM) with a good selectivity versus σ(2) binding. Among them, 18a had the lowest ClogD value (3.01) and only 19b was selective versus SI too. Generally, it was observed that more planar and hydrophilic heteronuclei conferred a decrease in affinity for both σ receptor subtypes. 相似文献
5.
Cassano G Gasparre G Contino M Niso M Berardi F Perrone R Colabufo NA 《Cell calcium》2006,40(1):23-28
In this paper we demonstrate that PB28 abolishes the Ca2+ release through the inositol 1,4,5-trisphosphate (InsP3) receptors and ryanodine receptors in SK-N-SH cells. Sigma receptors are divided into the subtypes sigma-1 and sigma-2, which are expressed in tumor cell lines and characterized by distinct pharmacological profiles. The sigma-1 receptor has been recently cloned, whereas the sigma-2 receptor is less well characterized. The endogenous ligand(s) of both subtypes remain unclear. In isolated guinea pig ileum, PB28 inhibits the contraction induced by carbachol dose dependently and in a non-competitive manner. In SK-N-SH cells PB28 challenge does not affect the intracellular Ca2+ concentration but incubation with PB28 for 45 min abolishes the cytosolic Ca2+ increases evoked by carbachol or histamine. This effect, not sensitive to cycloheximide, is caused by direct inhibition of the InsP3 receptors, since PB28 abolishes the response elicited by InsP3 administration in permeabilized SK-N-SH cells. Finally, incubation for 45 min with PB28 also abolishes the cytosolic Ca2+ increase evoked by caffeine. 相似文献
6.
Colabufo NA Abate C Contino M Inglese C Ferorelli S Berardi F Perrone R 《Bioorganic & medicinal chemistry letters》2008,18(6):2183-2187
A potent sigma-2 receptor ligand, known as PB28, was tritium radiolabelled and biologically evaluated. The results showed that [(3)H]PB28 and the corresponding unlabelled PB28 had superimposed pharmacodynamic properties. This radioligand appears as a potential candidate for receptor binding and in living cells assays. 相似文献
7.
Giuseppe Cassano Giuseppe Gasparre Mauro Niso Marialessandra Contino Vito Scalera Nicola Antonio Colabufo 《Cell calcium》2009,45(4):340-345
We demonstrate that F281, a synthetic agonist of the sigma-2 receptor (s2R), induces a non transient increase in intracellular [Ca2+] ([Ca2+]i) and cell death in SK-N-SH cells. Sigma receptors are classified into two subtypes, with different molecular weight and tissue distribution. While the sigma-1 receptor has been cloned, the s2r is less characterized and its physiological ligand and role need further investigation. In tumour cell lines, synthetic agonists of the s2R trigger apoptosis and modulate [Ca2+]i. In particular, CB-64D induces a Ca2+ response while PB28 supresses Ca2+ signalling. We have recently synthesized F281, by replacing the 5-methoxytetraline moiety of PB28 with a carbazole nucleus. Although this bioisosteric substitution should not affect the ligand affinity at the receptor, F281 (after 24 h incubation) was more cytotoxic than PB28 (EC50 values 65.4 nM and 8.13 μM, respectively) in SK-N-SH cells. We used the fluorescent probes fura-2, rhod-2 and JC-1. F281 mobilizes Ca2+ from mitochondria and from the endoplasmic reticulum, by opening its inositol 1,4,5-trisphosphate receptor; Ca2+-entry through the channels activated by store depletion was also observed. After the increase in [Ca2+]i and within 10 min, we observed a sudden drop in metabolic activity and intracellular [ATP] leading to cell death. 相似文献
8.
Marcello Leopoldo Enza Lacivita Paola De Giorgio Marialessandra Contino Francesco Berardi Roberto Perrone 《Bioorganic & medicinal chemistry》2009,17(2):758-766
In the search for compounds with potential for development as positron emission tomography radioligands for brain D3 receptor imaging, a series of N-[4-(4-arylpiperazin-1-yl)butyl]arylcarboxamides with appropriate lipophilicity (2 < log P < 3.5) were synthesized and tested in vitro. Some of the final compounds showed moderate-to-high dopamine D3 receptor affinities but lacked selectivity over D2 receptors. 相似文献
9.
Marialessandra Contino Laura Zinzi Maria Grazia Perrone Marcello Leopoldo Francesco Berardi Roberto Perrone Nicola Antonio Colabufo 《Bioorganic & medicinal chemistry letters》2013,23(5):1370-1374
Compounds 8a–d have been designed as bioisosters of tariquidar for imaging P-gp expression and density by PET. The results displayed that compounds 8b and 8d could be considered potential P-gp/BCRP ligands suitable as 11C and 18F radiotracers, respectively. 相似文献
10.
Rosa Chillemi Annalinda Contino Vincenzo Cucinotta Sebastiano Sciuto 《Nucleosides, nucleotides & nucleic acids》2013,32(4):953-962
Abstract A thermodynamic and proton NMR study has been carried out in order to characterize the behaviour of 2′-deoxyadenylyl-(3′→5′)-2′-deoxyadenosine towards the protonation. Conformational changes occurring following two protonation steps are discussed. 相似文献