Role of the ε subunit of thermophilic F1-ATPase as a sensor for ATP
Role of the ε subunit of thermophilic F1-ATPase as a sensor for ATP
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DOI：
10.1074/jbc.m707509200
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发表时间：
2007-12-28
影响因子：
4.8
通讯作者：
Kato-Yamada, Yasuyuki
中科院分区：
文献类型：
--
作者：
Kato, Shigeyuki;Yoshida, Masasuke;Kato-Yamada, Yasuyuki
来自嗜热芽孢杆菌PS 3（TF 1）的F-1-ATP酶的ATP亚基已被证明与ATP结合。ATP与β亚基结合的调节作用的确切性质仍有待确定。为了解决这个问题，制备了11个突变体的α亚基，其中一个碱性或酸性残基被丙氨酸取代。通过凝胶过滤色谱法测试ATP与这些突变体的结合。其中，选择了四个未显示ATP结合的突变体，并用TF 1的α（3）β（3）γ复合物重建。测量所得α（3）β（3）γ-ATP酶复合物的ATP酶活性，并比较每种情况下突变体ATP酶亚基的抑制程度。除了一个例外，较弱的ATP结合与ATP酶活性的更大抑制相关。这些结果清楚地表明，ATP结合到α亚基起着调节作用，ATP结合可以通过将α亚基固定到折叠构象中来稳定TF 1的ATP酶活性形式。
The epsilon subunit of F-1-ATPase from the thermophilic Bacillus PS3 (TF1) has been shown to bind ATP. The precise nature of the regulatory role of ATP binding to the epsilon subunit remains to be determined. To address this question, 11 mutants of the epsilon subunit were prepared, in which one of the basic or acidic residues was substituted with alanine. ATP binding to these mutants was tested by gel- filtration chromatography. Among them, four mutants that showed no ATP binding were selected and reconstituted with the alpha(3) beta(3) gamma complex of TF1. The ATPase activity of the resulting alpha(3)beta(3)gamma epsilon complexes was measured, and the extent of inhibition by the mutant epsilon subunits was compared in each case. With one exception, weaker binding of ATP correlated with greater inhibition of ATPase activity. These results clearly indicate that ATP binding to the epsilon subunit plays a regulatory role and that ATP binding may stabilize the ATPase- active form of TF1 by fixing the epsilon subunit into the folded conformation.