Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
J Biol Chem. 2011 Jul 15;286(28):25284-90. doi: 10.1074/jbc.M111.244616. Epub 2011 May 23.
Proteins interacting with membranes via a single hydrophobic segment can be classified as either monotopic or bitopic. Here, we probe the topology of a membrane-attached enzyme, the ε isoform of human diacylglycerol kinase (DGKε), when inserted into rough microsomes and compare it with the monotopic membrane protein mouse caveolin-1. In contrast to previous findings, the N-terminal hydrophobic stretch in DGKε attains a bitopic rather than a monotopic topology in our experimental system. In addition, we find that charged flanking residues as well as proline residues embedded in the hydrophobic segment are important determinants of monotopic versus bitopic topology.
通过单一疏水区与膜相互作用的蛋白质可以分为单跨膜和双跨膜蛋白。在这里，我们研究了一种与膜结合的酶——人二酰基甘油激酶 ε 同工型（DGKε）插入粗糙微粒体时的拓扑结构，并将其与单跨膜蛋白小鼠窖蛋白-1进行了比较。与先前的发现相反，在我们的实验系统中，DGKε 的 N 端疏水区段呈现出双跨膜拓扑结构，而不是单跨膜拓扑结构。此外，我们还发现，带电荷的侧翼残基以及嵌入疏水区段的脯氨酸残基是决定单跨膜还是双跨膜拓扑结构的重要因素。
