Meyer Etienne H, Heazlewood Joshua L, Millar A Harvey
ARC Center of Excellence in Plant Energy Biology, University of Western Australia, 4th Floor MCS Building M316, 35 Stirling Highway, 6009, Crawley, WA, Australia.
Plant Mol Biol. 2007 Jun;64(3):319-27. doi: 10.1007/s11103-007-9156-9. Epub 2007 Apr 4.
Arabidopsis mitochondria are predicted to contain three acyl carrier proteins (ACPs). These small proteins are involved in fatty acid and lipoic acid synthesis in other organisms and have been previously reported to be subunits of respiratory Complex I in mitochondria in mammals, fungi and plants. Recently, the mammalian mitochondrial ACP (mtACP) has been shown to be largely a soluble matrix protein but also to be minimally associated with Complex I (Cronan et al. 2005), consistent with its involvement in synthesis of lipoic acid for TCA cycle decarboxylating dehydrogenases in the matrix but contrary to earlier claims it was primarily a Complex I subunit. We have investigated the localization of the ACPs in Arabidopsis mitochondria. Evidence is presented that mtACP1 and mtACP2 dominate the ACP composition in Arabidopsis mitochondria, and both are present in the mitochondrial matrix rather than in the membrane. No significant amounts of mtACPs were detected in Complex I isolated by blue native gel electrophoresis, rather mtACPs were detected at low molecular mass in the soluble fraction, showing that in A. thaliana mtACPs are predominately free soluble matrix proteins.
拟南芥线粒体预计含有三种酰基载体蛋白（ACP）。这些小蛋白在其他生物体中参与脂肪酸和硫辛酸的合成，并且先前已有报道称它们是哺乳动物、真菌和植物线粒体中呼吸复合体I的亚基。最近，已表明哺乳动物线粒体ACP（mtACP）在很大程度上是一种可溶性基质蛋白，但与复合体I的关联程度极低（Cronan等人，2005年），这与其参与基质中三羧酸循环脱羧脱氢酶的硫辛酸合成相符，但与早期认为它主要是复合体I亚基的说法相反。我们研究了拟南芥线粒体中ACP的定位。有证据表明，mtACP1和mtACP2在拟南芥线粒体的ACP组成中占主导地位，且二者均存在于线粒体基质而非膜中。通过蓝色非变性凝胶电泳分离的复合体I中未检测到大量的mtACP，而是在可溶性部分中检测到低分子量的mtACP，这表明在拟南芥中，mtACP主要是游离的可溶性基质蛋白。
