| Project/Area Number |
05680584
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Biophysics
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| Research Institution | Fukuoka University |
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Principal Investigator |
LEE Sannamu Fukuoka University, Depart.of Chemistry, Research assistant, 理学部, 助手 (40248472)
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| Co-Investigator(Kenkyū-buntansha) |
ANZAI Kazunori Radioisotope Institute of Medicine, Chief researcher, 薬理部, 主任研究員 (70128643)
NAGADOME Shigemi Fukuoka University.Depart.of Chemistry, Research assistant, 理学部, 助手 (60180501)
SUGIHARA Gohsuke Fukuoka University, Depart.of Chemistry, Professor, 理学部, 教授 (50090915)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1994: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1993: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Molecular biology / Ion Channel / Membrane Protein / Peptide synthesis / Potassium Channel / Isk protein / Lipid-protein interaction / 立体構造解析 / 生物物理学 / 生体膜 / ペプチド / 蛋白質-脂質相互作用 / 生体膜貫通構造 |
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| Research Abstract |
A membrane protein, Isk, consisting of 130 amino acid residues with only a single transmembrane domain can form a voltage-gated potassium channel which can be opened or closed rapidly by changes in membrane potential in kidney, womb and heart of mammals. The single transmembrane domain is considered to form an alpha-helix by interacting with biomembrane and play a role as a constituent of the pore formed in the assembly of Isk protein monomers within membranes, resulting in the formation of a conducting pore. It is a matter of great interest to make clear the mechanism of the potassium ion selective channel formation by assembling of Isk proteins which have only one transmembrane domain consisting of hydrophobic amino acid residues. Thus, an investigation on the conformation of this portion and behavior of the assembly in membranes will lead to fundamental understanding of the nature of this protein. Therefore we synthesized a peptide of 40 residues containing the transmembrane domain corresponding to residues 38-77 (Isk-O) and its analog which is substituted Ala in Isk-0 for three Gly (Isk-A).
In the present study, Isk-0 took beta-structure in neutral and acidic liposomes and showed no channel formation. On the other hand, Isk-A resulted in a gradual increase in conductance followed by a constant conductance but did not exhibit channel-like opening and closing spikes.. Recent publications on the channel forming peptides and proteins have shown that beta-strands seem to be a part of the membrane spanning domain. The membrane spanning Isk domain hypothesized as an alpha-helical structure may adopt beta-structure or a mixture of alpha-helical and beta-structures in biological membranes.
Isk-0
H-Arg-Asp-Asp-Ser-Lys-Leu-Glu-Ala-Leu-Tyr-Ile-Leu-Met-Val-Leu-Gly-Phe-Phe-Gly-Phe-Phe-Thr-Leu-Gly-Ile-Met-Leu-Ser-Tyr-Ile-Arg-Ser-Lys-Lys-Leu-Glu-His-Ser-His-Asp-0H
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