Thome B M, Müller M
Institute of Biochemistry, University of Freiburg, Germany.
Mol Microbiol. 1991 Nov;5(11):2815-21. doi: 10.1111/j.1365-2958.1991.tb01990.x.
Skp of Escherichia coli (OmpH of Salmonella typhimurium) is a protein whose precise function has been obscured by its ubiquity in a wide range of subcellular fractions such as those containing DNA, ribosomes, and outer membranes. Combining in vitro and in vivo techniques we show that Skp is synthesized as a larger precursor that is processed upon translocation across the plasma membrane. Translocation is dependent on the H(+)-gradient, ATP, SecA, and SecY. Upon cellular subfractionation (avoiding non-specific electrostatic interactions) Skp partitions with beta-lactamase into the fraction of soluble, periplasmic proteins. In the context of the export factor properties of Skp previously demonstrated in vitro it is conceivable that this protein is involved in the later steps of protein translocation across the plasma membrane and/or sorting to the outer membrane.
大肠杆菌的Skp（鼠伤寒沙门氏菌的OmpH）是一种蛋白质，其确切功能因在广泛的亚细胞组分（如含有DNA、核糖体和外膜的组分）中普遍存在而变得模糊不清。结合体外和体内技术，我们发现Skp是以更大的前体形式合成的，该前体在跨质膜转运时会被加工。转运依赖于H(+)梯度、ATP、SecA和SecY。在细胞分级分离（避免非特异性静电相互作用）时，Skp与β-内酰胺酶一起分配到可溶性周质蛋白组分中。鉴于之前在体外证明的Skp的输出因子特性，可以设想这种蛋白质参与了蛋白质跨质膜转运和/或分选到外膜的后期步骤。
