Pollock R A, Hartl F U, Cheng M Y, Ostermann J, Horwich A, Neupert W
Department of Human Genetics, Yale University School of Medicine, New Haven, CT 06510.
EMBO J. 1988 Nov;7(11):3493-500. doi: 10.1002/j.1460-2075.1988.tb03225.x.
Two proteins co-operate in the proteolytic cleavage of mitochondrial precursor proteins: the mitochondrial processing peptidase (MPP) and the processing enhancing protein (PEP). In order to understand the structure and function of this novel peptidase, we have isolated mutants of Saccharomyces cerevisiae which were temperature sensitive in the processing of mitochondrial precursor proteins. Here we report on the mif2 mutation which is deficient in MPP. Mitochondria from the mif2 mutant were able to import precursor proteins, but not to cleave the presequences. The MPP gene was isolated. MPP is a hydrophilic protein consisting of 482 amino acids. Notably, MPP exhibits remarkable sequence similarity to PEP. We speculate that PEP and MPP have a common origin and have evolved into two components with different but mutually complementing functions in processing of precursor proteins.
线粒体加工肽酶（MPP）和加工增强蛋白（PEP）。为了了解这种新型肽酶的结构和功能，我们分离了酿酒酵母的突变体，这些突变体在线粒体前体蛋白的加工过程中对温度敏感。在此我们报告mif2突变，该突变体缺乏MPP。来自mif2突变体的线粒体能够导入前体蛋白，但不能切割前导序列。MPP基因被分离出来。MPP是一种由482个氨基酸组成的亲水性蛋白质。值得注意的是，MPP与PEP表现出显著的序列相似性。我们推测PEP和MPP有共同的起源，并在加工前体蛋白的过程中进化成了具有不同但相互补充功能的两个组分。
