Location of Subunit d in the Peripheral Stalk of the ATP Synthase from Saccharomyces cerevisiae

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• 作者：Stephanie A. Bueler ; John L. Rubinstein
• 刊名：Biochemistry
• 出版年：2008
• 出版时间：November 11, 2008
• 年：2008
• 卷：47
• 期：45
• 页码：11804-11810
• 全文大小：382K
• 年卷期：v.47,no.45(November 11, 2008)
• ISSN：1520-4995

文摘

ATP synthase from Saccharomyces cerevisiae is an ∼600 kDa membrane protein complex. The enzyme couples the proton motive force across the mitochondrial inner membrane to the synthesis of ATP from ADP and inorganic phosphate. The peripheral stalk subcomplex acts as a stator, preventing the rotation of the soluble F₁ region relative to the membrane-bound F_O region during ATP synthesis. Component subunits of the peripheral stalk are Atp5p (OSCP), Atp4p (subunit b), Atp7p (subunit d), and Atp14p (subunit h). X-ray crystallography has defined the structure of a large fragment of the bovine peripheral stalk, including 75% of subunit d (residues 3−123). Docking the peripheral stalk structure into a cryo-EM map of intact yeast ATP synthase showed that residue 123 of subunit d lies close to the bottom edge of F₁. The 37 missing C-terminal residues are predicted to either fold back toward the apex of F₁ or extend toward the membrane. To locate the C terminus of subunit d within the peripheral stalk of ATP synthase from S. cerevisiae, a biotinylation signal was fused to the protein. The biotin acceptor domain became biotinylated in vivo and was subsequently labeled with avidin in vitro. Electron microscopy of the avidin-labeled complex showed the label tethered close to the membrane surface. We propose that the C-terminal region of subunit d spans the gap from F₁ to F_O, reinforcing this section of the peripheral stalk.