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In a voltage-dependent sodium channel, the activation of voltage sensors upon depolarization leads to the opening of the pore gates. To elucidate the principles underlying this conformational coupling, we investigated a putative gating interface in domain III of the sodium channel using voltage-clamp fluorimetry and tryptophan-scanning mutagenesis. Most(More)
Voltage-dependent ion channels are crucial for generation and propagation of electrical activity in biological systems. The primary mechanism for voltage transduction in these proteins involves the movement of a voltage-sensing domain (D), which opens a gate located on the cytoplasmic side. A distinct conformational change in the selectivity filter near the(More)
Fish oil supplementation has been reported to be generally beneficial in autoimmune, inflammatory and cardiovascular disorders. Most researchers have attributed these beneficial effects to the high content of omega-3 fatty acids in fish oil (FO). The effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are not differentiated in most(More)
In the last decade, there has been renewed interest in biologically active peptides in fields like allergy, autoimmune diseases and antibiotic therapy. Mast cell degranulating peptides mimic G-protein receptors, showing different activity levels even among homologous peptides. Another important feature is their ability to interact directly with membrane(More)
Voltage-gated sodium channels are critical for the generation and propagation of electrical signals in most excitable cells. Activation of Na(+) channels initiates an action potential, and fast inactivation facilitates repolarization of the membrane by the outward K(+) current. Fast inactivation is also the main determinant of the refractory period between(More)
The hallmark of many intracellular pore blockers such as tetra-alkylammonium compounds and local anesthetics is their ability to allosterically modify the movement of the voltage sensors in voltage-dependent ion channels. For instance, the voltage sensor of domain III is specifically stabilized in the activated state when sodium currents are blocked by(More)
Free fatty acids (FFA) are important mediators of proton transport across membranes. However, information concerning the influence of the structural features of both FFA and the membrane environment on the proton translocation mechanisms across phospholipid membranes is relatively scant. The effects of FFA chain length, unsaturation and membrane composition(More)
Solid tumors tend to have a more glycolytic metabolism leading to an accumulation of acidic metabolites in their cytosol, and consequently, their intracellular pH (pHi) turns critically lower if the cells do not handle the acid excess. Recently, it was proposed that the voltage gated proton channels (HV1) can regulate the pHi in several cancers. Here we(More)
Eumenitin, a novel cationic antimicrobial peptide from the venom of solitary wasp Eumenes rubronotatus, was characterized by its effects on black lipid membranes of negatively charged (azolectin) and zwitterionic (1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC) or DPhPC-cholesterol) phospholipids: surface potential changes, single-channel activity, ion(More)
Jelleines are four naturally occurring peptides that comprise approximately eight or nine C-terminal residues in the sequence of the major royal jelly protein 1 precursor (Apis mellifera). The difference between these peptides is limited to one residue in the sequence, but this residue has a significant impact in their efficacy as antimicrobials. In(More)