Schleyer M, Neupert W
Cell. 1985 Nov;43(1):339-50. doi: 10.1016/0092-8674(85)90039-x.
Translocational intermediates of precursor proteins of ATPase F1 beta subunit and cytochrome c1 across mitochondrial membranes were analyzed using two different approaches, transport at low temperature and transport after binding of precursor proteins to antibodies. Under both conditions precursors were partially transported into mitochondria in an energy-dependent manner. They were processed by the metalloprotease in the matrix but a major proportion of the polypeptide chains was still present at the outer face of the outer mitochondrial membrane. We conclude that transfer of precursors into the inner membrane or matrix space occurs through "translocation contact sites"; precursor polypeptides to F1 beta and cytochrome c1 enter the matrix space with the amino terminus first; and a membrane potential is required for the transmembrane movement on an amino-terminal "domain-like" structure but not for completing translocation of the major part of the polypeptides.
采用两种不同方法分析了ATP酶F1β亚基和细胞色素c1前体蛋白跨线粒体膜的转运中间体，即低温转运和前体蛋白与抗体结合后的转运。在这两种条件下，前体蛋白均以能量依赖的方式部分转运至线粒体中。它们在基质中被金属蛋白酶加工处理，但大部分多肽链仍存在于线粒体外膜的外表面。我们得出结论：前体蛋白向内膜或基质空间的转移通过“转运接触位点”发生；F1β和细胞色素c1的前体多肽首先以氨基末端进入基质空间；跨膜运动在氨基末端“结构域样”结构上需要膜电位，但完成大部分多肽的转运则不需要。
