The modification of the conserved GXXXG motif of the membrane-spanning segment of subunit g destabilizes the supramolecular species of yeast ATP synthase
The modification of the conserved GXXXG motif of the membrane-spanning segment of subunit g destabilizes the supramolecular species of yeast ATP synthase
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DOI：
10.1074/jbc.m502140200
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发表时间：
2005-08-12
影响因子：
4.8
通讯作者：
Velours, J
中科院分区：
文献类型：
--
作者：
Bustos, DM;Velours, J
在所有线粒体三磷酸腺苷合成酶中都发现了额外的亚基g。大多数保守的氨基酸残基存在于含有二聚化基序GXXXG的蛋白质的膜C末端部分。在酵母中，这个基序的改变导致ATP合成酶g亚基和超分子结构的丢失，并伴随着异常线粒体形态的出现。G亚基109位的工程半胱氨酸与e亚基的内源性半胱氨酸28形成二硫键，促进g+g、e+g和e+e加合物，从而揭示了线粒体膜上几个亚基e和g的接近。线粒体中两个亚基g之间的二硫键形成增加了洋地黄素提取物中ATP合成酶低聚结构的稳定性。这些数据表明，g亚基的二聚化基序参与了超分子结构的形成，并有利于线粒体内膜上存在质量高于ATP合成酶二聚体的ATP合成酶缔合。
The supernumerary subunit g is found in all mitochondrial ATP synthases. Most of the conserved amino acid residues are present in the membrane C-terminal part of the protein that contains a dimerization motif GXXXG. In yeast, alteration of this motif leads to the loss of subunit g and of supramolecular structures of the ATP synthase with concomitant appearance of anomalous mitochondrial morphologies. Disulfide bond formation involving an engineered cysteine in position 109 of subunit g and the endogenous cysteine 28 of subunit e promoted g + g, e + g, and e + e adducts, thus revealing the proximity in the mitochondrial membrane of several subunits e and g. Disulfide bond formation between two subunits g in mitochondria increased the stability of an oligomeric structure of the ATP synthase in digitonin extracts. These data suggest the participation of the dimerization motif of subunit g in the formation of supramolecular structures and is in favor of the existence of ATP synthase associations, in the inner mitochondrial membrane, whose masses are higher than those of ATP synthase dimers.