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Coexpression of the betawt and alphawt subunits of the bovine rod channel restores two characteristics of the native channels: higher sensitivity to cAMP and potentiation of cGMP-induced currents by low cAMP concentrations. To test whether the increased sensitivity to cAMP is due to the uncharged nature of the asparagine residue (N1201) situated in place of(More)
Single channels are observed after incorporation of native vesicles from bovine rod outer segment membranes into planar lipid bilayers. The activity of a single channel in the presence of cGMP is compared to that induced by the analog 8-bromo-cGMP and by cAMP. At +80 mV, K 0.5 is about 3 μm for 8Br-cGMP, 18 μm for cGMP and 740 μm for cAMP. In cAMP, the(More)
The gating transition of the RR and SS dioxolane ring-linked gramicidin A channels were studied with molecular dynamics simulations using a detailed atomic model. It was found that the probable reaction path, describing the transition of the ring from the exterior to the interior of the channel where it blocked the permeation pathway, involved several steps(More)
TEA is a classical blocker of K(+) channels. From mutagenesis studies, it has been shown that external blockade by TEA is strongly dependent upon the presence of aromatic residue at Shaker position 449 which is located near the extracellular entrance to the pore (Heginbotham, L., and R. MacKinnon. 1992. Neuron. 8:483-491). The data suggest that TEA(More)
The cationic conductances of purified bovine retinal rod membranes were studied by incorporation of vesicles into planar lipid bilayers. When the membranes were stripped of all peripheral proteins [guanine nucleotide-binding protein (G protein) and cGMP phosphodiesterase (3',5'-cyclic-GMP 5'-nucleotidohydrolase), EC 3.1.4.35], sodium and calcium fluxes were(More)
Transmissible subacute spongiform encephalopathies (TSE) are animal and human neurodegenerative diseases. The nature of the transmissible agent remains unknown. The specific molecular marker of these diseases is the abnormal isoform of the prion protein (PrP). This protein is encoded by a cellular gene and accumulates in a pathological isoform (PrPres)(More)
In MerT, the mercury transporter, a first cysteine pair, located in the first trans-membrane helix, receives mercury from the periplasm. Then, a second cysteine pair, housed in a cytoplasmic loop connecting the second and the third trans-membrane helices, is thought to transfer the metal to another cysteine pair located in the N-terminal extension of the(More)
Molecular dynamics simulations of an atomic model of the transmembrane domain of the oncogenic ErbB2 receptor dimer embedded in an explicit dimyristoylphosphatidylcholine (DMPC) bilayer were performed for more than 4 ns. The oncogenic Glu mutation in the membrane spanning segment plays a major role in tyrosine kinase activity and receptor dimerization, and(More)
A nuclear magnetic resonance (NMR) spectroscopy and molecular modeling study of the interaction between alpha-cyclodextrin (alpha-CD) and phospholipids with serine, ethanolamine, or choline headgroups is presented. The experimental approach is based on 31P and 1H NMR measurements on small unilamellar vesicles (SUV), multilamellar systems (MLV), and aqueous(More)
The ATP-binding cassette is the most abundant family of transporters including many medically relevant members and gathers both importers and exporters involved in the transport of a wide variety of substrates. Although three high resolution three-dimensional structures have been obtained for a prototypic exporter, MsbA, two have been subjected to much(More)