De Silvestris M, D'Arrigo A, Borgese N
C.N.R. Center for Cytopharmacology, Milano, Italy.
FEBS Lett. 1995 Aug 14;370(1-2):69-74. doi: 10.1016/0014-5793(95)00797-d.
Two isoforms of mammalian cytochrome b5, which have homologous cytosolic amino-terminal catalytic domains, are located one on endoplasmic reticulum (ER b5) the other on mitochondrial outer membranes (OM b5). A cDNA coding for the previously unknown carboxyl-terminal domain of OM b5 was cloned and a chimera between the catalytic domain of ER b5 and the carboxyl-terminal region of OM b5 was expressed in cultured mammalian cells. The chimera localized to mitochondria, indicating that the carboxyl-terminal 43 amino acids of OM b5 contain sufficient information to target the catalytic domain of ER b5 to the mitochondrial outer membrane.
哺乳动物细胞色素b5有两种同工型，它们具有同源的胞质氨基末端催化结构域，一种位于内质网（内质网b5），另一种位于线粒体外膜（线粒体外膜b5）。克隆了编码此前未知的线粒体外膜b5羧基末端结构域的cDNA，并在培养的哺乳动物细胞中表达了内质网b5催化结构域与线粒体外膜b5羧基末端区域之间的嵌合体。该嵌合体定位于线粒体，这表明线粒体外膜b5的羧基末端43个氨基酸包含将内质网b5催化结构域靶向线粒体外膜的足够信息。
