Oligomer structure and functional regulation in cation pumps

阳离子泵中的低聚物结构和功能调节

• 批准号: 10044048
• 负责人: TANIGUCHI Kazuya
• 金额: $ 7.74万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A).
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10044048/
• 关键词: Na; K-ATPase; oligomer; P-Type ATPase; Post Albers Scheme; tetraprotomer; H; リン酸化; フォスファターゼ; 構造変化; Naポンプ; Hポンプ

Since the discovery of Na/K-ATPase, evidence has accumulated to suggest that 1 mol of ATP hydrolysis occurs via the Na^+-occluded ADP-sensitive phosphoenzyme, the K^+- sensitive phoshphoenzyme and the K^+-occluded enzyme accompanying active transport of 3Na^+ and 2K^+ according the Post-Albers sheme. However, some controversial issues have arisen concerning whether the functional unit of the enzyme is an αβ-protomer or a much higher oligomer, which would be related to the mechanism of transport, either sequential or simultaneous. Detailed studies of oligomer interaction and the reactivity of the enzyme and a comparison of the extent of phosphorylation with ligand-binding capacities in the presence or absence of ATP hydrolysis and others strongly suggest that the functional unit of the enzyme in the membrane is a tetraprotomer, (αβ)_4. They also suggest that each reaction intermediate of the Post-Albers scheme, respectively, reflects half of the site property of the intermediate and that another half binds ATP.These data may be useful not only to answer the long-standing question of whether the mechanism functions in the presence of both Na^+ and K^+ but also contribute to a better understanding of the mechanism of P-type pump ATPase in general.

自从发现Na/k-ATPase以来，有证据表明1摩尔的ATP水解是通过Na^+ - 封闭的ADP敏感磷酸酶，K^+ - 闭塞酶，经过3NA^+和2K^+的活性转运。然而，关于酶的功能单位是αβ-螺旋体还是更高的低聚物，这与某些有争议的问题有关，这与顺序还是简单的转运机理有关。在存在或不存在ATP水解的情况下，酶相互作用和磷酸化程度与配体结合能力的详细研究以及磷酸化程度与配体结合能力的比较，而其他磷酸化程度则强烈表明该酶的功能单位是膜中的功能单位是Tetraptrotomer，（αβ）_4。他们还表明，后albers方案的每个反应中间体都反映了中间体的位点特性的一半，另一半结合了ATP。这些数据不仅可以回答长期存在的问题，即该机制是否在Na^+和K^+的存在下起作用，而且还有助于更好地理解P型泵ATPase的机制。

项目成果

T.Imagawa: "Does Binding of Ouabain to Human α1 Subunit of Na,K-ATPase Affect the ATPase Activity of Adjacent Rat α1 Subunit?" Jpn.J.Pharmacal.vol.76. 415-423 (1998)

T.Imakawa：“哇巴因与人 Na,K-ATP 酶 α1 亚基的结合会影响相邻大鼠 α1 亚基的 ATP 酶活性吗？”Jpn.J.Pharmacal.vol.76 (1998)。

K.Taniguchi, et.al.: "New aspects of Na/K-ATPase : Acid labile ATP and/or ADP/Pi binding to the tetraprotomer, (αβ)_4"Control and Diseases of Sodium Dependent Transport Proteins and Ion Channels (Y.Suketa, E.Carafoli et. al. eds.). 15-18 (2000)

K.Taniguchi 等人：“Na/K-ATP 酶的新方面：酸不稳定 ATP 和/或 ADP/Pi 与四原体结合，(αβ)_4”钠依赖性转运蛋白和离子通道的控制和疾病（ Y.Suketa，E.Carafoli 等人。15-18 (2000)。

T.Yokoyama, et. al.: "ATP induced fluorescence changes of a bipm and an rh-421 probes in pig kidney Na/K-ATPase"The Na/K-ATPase and Related ATPases (K.Taniguchi and S.Kaya eds.). 237-240 (2000)

T.横山，等。

T.Yokoyama, et. al.: "Acid-Iabile ATP and/or ADP/Pi binding to the tetraprotomeric form of Na/K-ATPase accompanying catalytic phosphorylation-dephosphorylation cycle"J.Biol.Chem.. 274. 31792-31796 (1999)

T.横山，等。

T.Tsuda, et.al.: "ATP and Acetyl Phosphate Induces Molecular Events near the ATP Binding Site and the Membrane Domain of Na^+, K^+-ATPase."J.Biol.Chem.. 273. 24339-24345 (1998)

T.Tsuda 等人：“ATP 和乙酰磷酸在 ATP 结合位点和 Na+、K+-ATP 酶膜结构域附近诱导分子事件。”J.Biol.Chem.. 273. 24339-24345 (1998)