Elisabeth Vales

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The closely related TRPC4 and TRPC5 proteins, members of the canonical transient receptor potential (TRPC) family, assemble into either homo- or heterotetrameric, non-selective cation-channels. To elucidate domains that mediate channel complex formation, we evaluated dominant negative effects of N- or C-terminal TRPC4/5 fragments on respective currents of(More)
In the current study, we found that NaCl induces fast vesicle fusion and aggregation of the bacterial potassium channel KcsA in Escherichia coli (E. coli) membranes. Conventional gel electrophoresis and tryptophan fluorescence experiments were performed to detect NaCl-induced aggregation or supramolecular complexes. Interestingly, in a planar lipid bilayer,(More)
All K(+)-channels are stabilized by K(+)-ions in the selectivity filter. However, they differ from each other with regard to their selectivity filter. In this study, we changed specific residue Val-76 in the selectivity filter of KcsA to its counterpart Ile in inwardly rectifying K(+)-channels (Kir). The tetramer was exclusively converted into monomers as(More)
The reconstitution of large amounts of integral proteins into lipid vesicles is largely prompted by the complexity of most biological membranes and protein stability. We optimized a particular system which maximized the incorporation efficiency of large soluble amounts of KcsA potassium channel in Escherichia coli membranes. The effects of two detergents,(More)
In this study, we compared the channel intrinsic stability of the bacterial K(+)-channel KcsA and the inwardly rectifying potassium channel (Kir) ROMK1. ROMK1 was successfully cloned, expressed and purified from Saccharomyces cerevisae. By conventional gel electrophoresis, ROMK1 was detected in monomeric form running exclusively at approximately 45 kDa(More)
The bacterial potassium (K(+)) channel KcsA provides an attractive model system to study ion permeation behavior in a selective K(+)-channel. We changed residue at the N-terminal end of the selectivity filter of KcsA (T74V) to its counterpart in inwardly rectifying K(+)-channels (Kir). The tetramer was found to be stable as unmodified KcsA. Under(More)
Recent advances in structural biology underlying mechanisms of channel gating have strengthened our knowledge about how K(+) channels can be inter-convertible between conductive and non-conductive states. We have reviewed and combined mutagenesis with biochemical, biophysical and structural information in order to understand the critical roles of the pore(More)
Mutation E71A in the bacterial K+-channel KcsA has been shown to abolish the activation-coupled inactivation of KcsA via significant alterations of the peptide backbone in the vicinity of the selectivity filter. In the present study, we examined channel-blocking behavior of KcsA-E71A by tetraethylammonium (TEA) from both the extra- and the intracellular(More)
Protein aggregation is a result of malfunction in protein folding, assembly, and transport, caused by protein mutation and/or changes in the cell environment, thus triggering many human diseases. We have shown that bacterial K+-channel KcsA, which acts as a representative model for ion channels, forms salt-induced large conductive complexes in a particular(More)
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