Biomaterial Database

Surface Charges of K channels. Effects of strontium on five cloned channels expressed in Xenopus oocytes. 1996

F Elinder, and M Madeja, and P Arhem

Nobel Institute for Neurophysiology, Karolinska Institutet, Stockholm, Sweden.

The effects of strontium (Sr2+; 7-50 mM) on five different cloned rat K channels (Kv1.1, Kv1.5, Kv1.6, Kv2.1, and Kv3.4), expressed in oocytes of Xenopus laevis, were investigated with a two-electrode voltage clamp technique. The main effect was a shift of the Gk(V) curve along the potential axis, different in size for the different channels. Kv1.1 was shifted most and Kv3.4 least, 21 and 8 mV, respectively, at 50 mM. The effect was interpreted in terms of screening of fixed surface charges. The estimated charge densities ranged from -0.37 (Kv1.1) to -0.11 (Kv3.4) e nm-2 and showed good correlation with the total net charge of the extracellularly located amino acid residues of the channel as well as with the charge of a specific region (the loop between the S5 segment and the pore forming segment). The estimated surface potentials were found to be linearly related to the activation midpoint potential, suggesting a functional role for the surface charges.

UI	MeSH Term	Description	Entries
D009865	Oocytes	Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).	Ovocytes,Oocyte,Ovocyte
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D004553	Electric Conductivity	The ability of a substrate to allow the passage of ELECTRONS.	Electrical Conductivity,Conductivity, Electric,Conductivity, Electrical
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D005260	Female		Females
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013324	Strontium	An element of the alkaline earth family of metals. It has the atomic symbol Sr, atomic number 38, and atomic weight 87.62.
D014982	Xenopus laevis	The commonest and widest ranging species of the clawed "frog" (Xenopus) in Africa. This species is used extensively in research. There is now a significant population in California derived from escaped laboratory animals.	Platanna,X. laevis,Platannas,X. laevi
D015221	Potassium Channels	Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.	Ion Channels, Potassium,Ion Channel, Potassium,Potassium Channel,Potassium Ion Channels,Channel, Potassium,Channel, Potassium Ion,Channels, Potassium,Channels, Potassium Ion,Potassium Ion Channel