Wilkens Stephan, Borchardt Dan, Weber Joachim, Senior Alan E
Departments of Biochemistry, University of California at Riverside, Riverside, California 92521, USA.
Biochemistry. 2005 Sep 6;44(35):11786-94. doi: 10.1021/bi0510678.
A critical point of interaction between F(1) and F(0) in the bacterial F(1)F(0)-ATP synthase is formed by the alpha and delta subunits. Previous work has shown that the N-terminal domain (residues 3-105) of the delta subunit forms a 6 alpha-helix bundle [Wilkens, S., Dunn, S. D., Chandler, J., Dahlquist, F. W., and Capaldi, R. A. (1997) Nat. Struct. Biol. 4, 198-201] and that the majority of the binding energy between delta and F(1) is provided by the interaction between the N-terminal 22 residues of the alpha- and N-terminal domain of the delta subunit [Weber, J., Muharemagic, A., Wilke-Mounts, S., and Senior, A. E. (2003) J. Biol. Chem. 278, 13623-13626]. We have now analyzed a 1:1 complex of the delta-subunit N-terminal domain and a peptide comprising the N-terminal 22 residues of the alpha subunit by heteronuclear protein NMR spectroscopy. A comparison of the chemical-shift values of delta-subunit residues with and without alpha N-terminal peptide bound indicates that the binding interface on the N-terminal domain of the delta subunit is formed by alpha helices I and V. NOE cross-peak patterns in 2D (12)C/(12)C-filtered NOESY spectra of the (13)C-labeled delta-subunit N-terminal domain in complex with unlabeled peptide verify that residues 8-18 in the alpha-subunit N-terminal peptide are folded as an alpha helix when bound to delta N-terminal domain. On the basis of intermolecular contacts observed in (12)C/(13)C-filtered NOESY experiments, we describe structural details of the interaction of the delta-subunit N-terminal domain with the alpha-subunit N-terminal alpha helix.
细菌F(1)F(0)-ATP合酶中F(1)和F(0)之间相互作用的一个关键点由α和δ亚基形成。先前的研究表明，δ亚基的N端结构域（第3至105位氨基酸残基）形成一个6α-螺旋束[威尔肯斯，S.，邓恩，S. D.，钱德勒，J.，达尔奎斯特，F. W.，和卡帕尔迪，R. A.（1997年）《自然结构生物学》4，198 - 201]，并且δ与F(1)之间的大部分结合能由α亚基N端的22个氨基酸残基与δ亚基N端结构域之间的相互作用提供[韦伯，J.，穆哈雷马吉克，A.，威尔克 - 芒茨，S.，和西尼尔，A. E.（2003年）《生物化学杂志》278，13623 - 13626]。我们现在通过异核蛋白质核磁共振光谱分析了δ亚基N端结构域与包含α亚基N端22个氨基酸残基的肽段形成的1:1复合物。比较结合和未结合α亚基N端肽段时δ亚基氨基酸残基的化学位移值表明，δ亚基N端结构域上的结合界面由α螺旋I和V形成。在与未标记肽段形成复合物的(13)C标记的δ亚基N端结构域的二维(12)C/(12)C滤波NOESY光谱中的NOE交叉峰模式证实，α亚基N端肽段中的第8至18位氨基酸残基在与δ亚基N端结构域结合时折叠成α螺旋。基于在(12)C/(13)C滤波NOESY实验中观察到的分子间相互作用，我们描述了δ亚基N端结构域与α亚基N端α螺旋相互作用的结构细节。
