Synthetic Peptide Fragments as Probes for Structure Determination of Potassium Ion-Channel Proteins

1998 ◽  
Vol 18 (6) ◽  
pp. 299-312 ◽  
Author(s):  
Parvez I. Haris
Keyword(s):  
Potassium Channels ◽  
Ion Channel ◽  
Potassium Channel ◽  
Synthetic Peptide ◽  
Potassium Ion ◽  
Channel Structure ◽  
Phospholipid Membranes ◽  
Peptide Fragments ◽  
2D Nmr Spectroscopy ◽  
Channel Proteins

Potassium channels are a diverse class of transmembrane proteins that are responsible for diffusion of potassium ion across cell membranes. The lack of large quantities of these proteins from natural sources, is a major hindrance in their structural characterization using biophysical techniques. Synthetic peptide fragments corresponding to functionally important domains of these proteins provide an attractive approach towards characterizing the structural organization of these ion-channels. Conformational properties of peptides from three different potassium channels (Shaker, ROMK1 and minK) have been characterized in aqueous media, organic solvents and in phospholipid membranes. Techniques used for these studies include FTIR, CD and 2D-NMR spectroscopy. FTIR spectroscopy has been a particularly valuable tool for characterizing the folding of the ion-channel peptides in phospholipid membranes; the three different types of potassium channels all share a common transmembrane folding pattern that is composed of a predominantly α-helical structure. There is no evidence to suggest the presence of any significant β-sheet structure. These results are in excellent agreement with the crystal structure of a bacterial potassium channel (Doyle, D. A. et al. (1998) Science280:69–77), and suggest that all potassium channel proteins may share a common folding motif where the ion-channel structure is constructed entirely from α-helices.

scholarly journals The study of sodium and potassium channel gene single-nucleotide variation significance in non-mechanical forms of epilepsy

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Ozada Khamdiyeva ◽  
Zhanerke Tileules ◽  
Gulminyam Baratzhanova ◽  
Anastassiya Perfilyeva ◽  
Leyla Djansugurova
Keyword(s):  
Ion Channel ◽  
Potassium Channel ◽  
De Novo ◽  
Potassium Ion ◽  
Dravet Syndrome ◽  
De Novo Mutations ◽  
Single Nucleotide ◽  
Channel Gene ◽  
Sodium And Potassium ◽  
Potassium Channel Gene

Abstract Background Epilepsy is one of the most common and heterogeneous neurological diseases. The main clinical signs of the disease are repeated symptomatic or idiopathic epileptic seizures of both convulsive and non-convulsive nature that develop against a background of lost or preserved consciousness. The genetic component plays a large role in the etiology of idiopathic forms of epilepsy. The study of the molecular genetic basis of neurological disorders has led to a rapidly growing number of gene mutations known to be involved in hereditary ion channel dysfunction. The aim of this research was to evaluate the involvement of single-nucleotide variants that modify the function of genes (SCN1A, KCNT1, KCNTС1, and KCNQ2) encoding sodium and potassium ion channel polypeptides in the development of epilepsy. Results De novo mutations in the sodium channel gene SCN1A c.5347G>A (p. Ala1783Thr) were detected in two patients with Dravet syndrome, with a deletion in exon 26 found in one. Three de novo mutations in the potassium channel gene KCNT1 c.2800G>A (p. Ala934Thr), were observed in two patients with temporal lobe epilepsy (TLE) and one patient with residual encephalopathy. Moreover, a control cohort matched to the case cohort did not reveal any SNVs among conditionally healthy individuals, supporting the pathogenic significance of the studied SNVs. Conclusion Our results are supported by literature data showing that the sodium ion channel gene SCN1A c.5347G>A mutation may be involved in the pathogenesis of Dravet syndrome. We also note that the c.2800G>A mutation in the potassium channel gene KCNT1 can cause not only autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) but also other forms of epilepsy. To treat pathogenetic mutations that accelerate the function of sodium and potassium ion channels, we recommend ion channel blockade drug therapy.

Ion channels and disease

2020 ◽  
pp. 246-255
Author(s):  
Frances Ashcroft ◽  
Paolo Tammaro
Keyword(s):  
Ion Channels ◽  
Ion Channel ◽  
Single Channel ◽  
Cell Types ◽  
Channel Structure ◽  
Channel Proteins ◽  
Channel Function ◽  
Ion Channel Proteins ◽  
Single Channel Currents ◽  
Channel Currents

Ion channels are membrane proteins that act as gated pathways for the movement of ions across cell membranes. They are found in both surface and intracellular membranes and play essential roles in the physiology of all cell types. An ever-increasing number of human diseases are now known to be caused by defects in ion channel function. To understand how ion channel defects give rise to disease, it is helpful to understand how the ion channel proteins work. This chapter therefore considers what is known of ion channel structure, explains the properties of the single ion channel, and shows how single-channel currents give rise to action potentials and synaptic potentials.

scholarly journals Protein ligands for studying ion channel proteins

2017 ◽  
Vol 149 (4) ◽  
pp. 407-411
Author(s):  
Tanmay Chavan ◽  
Merritt Maduke ◽  
Kenton Swartz
Keyword(s):  
Potassium Channels ◽  
Ion Channel ◽  
Scorpion Toxin ◽  
Protein Ligands ◽  
Channel Proteins ◽  
Ion Channel Proteins

Chavan et al. highlight work showing that a monobody can inhibit a fluoride channel using a mechanism similar to that of a scorpion toxin blocker of potassium channels.

Ion Channels in Plants

2012 ◽  
Vol 92 (4) ◽  
pp. 1777-1811 ◽  
Author(s):  
Rainer Hedrich
Keyword(s):  
Plasma Membrane ◽  
Ion Channels ◽  
Patch Clamp ◽  
Ion Channel ◽  
Potassium Channel ◽  
Guard Cells ◽  
Channel Structure ◽  
Model Systems ◽  
Dependent Manner ◽  
Inward Rectifiers

Since the first recordings of single potassium channel activities in the plasma membrane of guard cells more than 25 years ago, patch-clamp studies discovered a variety of ion channels in all cell types and plant species under inspection. Their properties differed in a cell type- and cell membrane-dependent manner. Guard cells, for which the existence of plant potassium channels was initially documented, advanced to a versatile model system for studying plant ion channel structure, function, and physiology. Interestingly, one of the first identified potassium-channel genes encoding the Shaker-type channel KAT1 was shown to be highly expressed in guard cells. KAT1-type channels from Arabidopsis thaliana and its homologs from other species were found to encode the K+-selective inward rectifiers that had already been recorded in early patch-clamp studies with guard cells. Within the genome era, additional Arabidopsis Shaker-type channels appeared. All nine members of the Arabidopsis Shaker family are localized at the plasma membrane, where they either operate as inward rectifiers, outward rectifiers, weak voltage-dependent channels, or electrically silent, but modulatory subunits. The vacuole membrane, in contrast, harbors a set of two-pore K+ channels. Just very recently, two plant anion channel families of the SLAC/SLAH and ALMT/QUAC type were identified. SLAC1/SLAH3 and QUAC1 are expressed in guard cells and mediate Slow- and Rapid-type anion currents, respectively, that are involved in volume and turgor regulation. Anion channels in guard cells and other plant cells are key targets within often complex signaling networks. Here, the present knowledge is reviewed for the plant ion channel biology. Special emphasis is drawn to the molecular mechanisms of channel regulation, in the context of model systems and in the light of evolution.

scholarly journals The scorpion toxin and the potassium channel

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Kenton J Swartz
Keyword(s):  
Ion Channel ◽  
Potassium Channel ◽  
Potassium Ion ◽  
Scorpion Toxin ◽  
Potassium Ions ◽  
Potassium Ion Channel ◽  
First Time

The structure of a complex containing a toxin bound to a potassium ion channel has been solved for the first time, revealing how scorpions have designed toxins that can recognize and target the filter that controls the movement of potassium ions through these channels.

Regulation of ion channel structure and function by reactive oxygen-nitrogen species

2003 ◽  
Vol 285 (6) ◽  
pp. L1184-L1189 ◽  
Author(s):  
Sadis Matalon ◽  
Karin M. Hardiman ◽  
Lucky Jain ◽  
Douglas C. Eaton ◽  
Michael Kotlikoff ◽  
...  
Keyword(s):  
Gene Expression ◽  
Ion Channels ◽  
Ion Channel ◽  
Posttranslational Modifications ◽  
Regulation Of Gene Expression ◽  
Reactive Oxygen ◽  
Cellular Level ◽  
Channel Structure ◽  
Nitrogen Species ◽  
Channel Proteins

Ion channels subserve diverse cellular functions. Reactive oxygen and nitrogen species modulate ion channel function by a number of mechanisms including 1) transcriptional regulation of gene expression, 2) posttranslational modifications of channel proteins, i.e. nitrosylation, nitration, and oxidation of key amino acid residues, 3) by altering the gain in other signaling pathways that may in turn lead to changes in channel activity or channel gene expression, and 4) by modulating trafficking or turnover of channel proteins, as typified by oxygen radical activation of NF-kB, with subsequent changes in proteasomal degradation of channel degradation. Regardless of the mechanism, as was discussed in a symposium at the 2003 Experimental Biology Meeting in San Diego, CA, changes in the cellular level of reactive oxygen and nitrogen species can have profound effects on the activity of ion channels and cellular function.

scholarly journals Phycodnavirus Potassium Ion Channel Proteins Question the Virus Molecular Piracy Hypothesis

PLoS ONE ◽  
2012 ◽  
Vol 7 (6) ◽  
pp. e38826 ◽  
Author(s):  
Kay Hamacher ◽  
Timo Greiner ◽  
Hiroyuki Ogata ◽  
James L. Van Etten ◽  
Manuela Gebhardt ◽  
...  
Keyword(s):  
Ion Channel ◽  
Potassium Ion ◽  
Potassium Ion Channel ◽  
Channel Proteins ◽  
Ion Channel Proteins
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