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Membrane proteins function in a polarized ionic environment with sodium-rich extracellular and potassium-rich intracellular solutions. Glutamate receptors that mediate excitatory synaptic transmission in the brain show unusual sensitivity to external ions, resulting in an apparent requirement for sodium in order for glutamate to activate kainate receptors.(More)
Ionotropic GABA receptors are abundant in both vertebrate and invertebrate nervous systems, where they mediate rapid, mostly inhibitory synaptic transmission. A GABA-gated chloride channel subunit from Drosophila melanogaster [Resistant to Dieldrin (RDL)] has been cloned, functionally expressed, and found to exhibit many aspects of the pharmacology of(More)
Nicotinic acetylcholine receptors (nAChRs) are important for fast synaptic cholinergic transmission. They are targets of drugs/chemicals for human and animal health as well as for pest control. With the advent of genome sequencing, entire nAChR gene families have now been described for vertebrates and invertebrates. Mostly, these are extensive with a large(More)
Cecropins are positively charged antibacterial peptides that act by permeating the membrane of susceptible bacteria. To gain insight into the mechanism of membrane permeation, the secondary structure and the orientation within phospholipid membranes of the mammalian cecropin P1 (CecP) was studied using attenuated total reflectance Fourier-transform infrared(More)
Molecular dynamics simulations of a bacterial potassium channel (KcsA) embedded in a phospholipid bilayer reveal significant differences in interactions of the selectivity filter with K(+) compared with Na(+) ions. K(+) ions and water molecules within the filter undergo concerted single-file motion in which they translocate between adjacent sites within the(More)
Ion channels contain extended columns of water molecules within their transbilayer pores. The dynamic properties of such intrapore water have been shown to differ from those of water in its bulk state. In previous molecular dynamics simulations of two classes of model pore (parallel bundles of Ala20 alpha-helices and antiparallel barrels of Ala10(More)
The alpha4beta2 subtype is the most abundant nicotinic acetylcholine receptor (nAChR) in the brain and possesses the high-affinity binding site for nicotine. The alpha4 and beta2 nAChR subunits assemble into two alternate stoichiometries, (alpha4)(2)(beta2)(3) and (alpha4)(3)(beta2)(2), which differ in their functional properties and sensitivity to chronic(More)
The structure of the bacterial potassium channel, KcsA, corresponds to the channel in a closed state. Two lines of evidence suggest that the channel must widen its intracellular mouth when in an open state: 1) internal block by a series of tetraalkylammonium ions and 2) spin labeling experiments. Thus it is known that the protein moves in this region, but(More)
The ligand-binding domain (LBD) from the ionotropic glutamate receptor subtype 2 (GluR2) has been shown to adopt a range of ligand-dependent conformational states. These states have been described in terms of the rotation required to fit subdomain (lobe) 2 following superposition of subdomain (lobe) 1. The LBD has a closed-cleft conformation for full(More)