Importance of Multi-phosphate Lipid for Regulating the Initiator of Gene replication.

大多数生物脂是由一个亲水基团和双烷基链组成的。除了这些典型的脂质外，人们还可以发现一种具有双亲水性头的四链脂质，即心磷脂（CL）。CL中的双重结构对于物理化学稳定双层膜本身显然是多余的。然而，最近有报道称，这种双重结构可以作为大肠杆菌DNA复制的启动剂DnaA蛋白的遗传因子。对我们来说，在CL中通过一个甘油单元来桥接两个磷酸盐似乎是一个关键。通过系统合成各种双磷酸脂，我们发现两个具有疏水性的磷酸基团在膜上的协同作用对与dna蛋白的相互作用起着至关重要的作用。为了推广双磷酸形式在脂质中的作用，我们还发现双磷酸脂质不仅影响dna蛋白，而且影响Cyt.c的构象和活性。在蛋白质结合的情况下，桥接中的羟基是激活酶的关键基团，在本研究中，我们得出结论，甘油双头桥接对酶的激活非常重要。

Most of biolipids are comprised of a single hydrophilic group and double alkyl chains. Besides these typical lipids, one can find out a four-chained lipid with a double hydrophilic head, cardiolipin (CL). The double structure in CL is apparently redundant for physicochemically stabilizing bilayer membrane itself. However, it has been recently reported hat the double structure can be used as a genetic factor for DnaA protein, the initiator of DNA replication of Escherichia coli. It seems for us to be a key to bridge the two phosphates by a glycerol unit in CL.Through systematically synthesizing various double phosphate lipids, herein we show that cooperative action by the two phosphate groups possessing somewhat hydrophobic property on membrane would play a crucial role for interaction with DnaA protein. For generalizing the role of the double phosphate form in lipid, we also find that the double phosphate lipid has influence over the conformation and activity of Cyt.c, not only on the DnaA protein. In the case of the protein binding, the hydroxy group in the bridge is a key group for activating the enzymes, In this study, we conclude that the double head bridging a glycerol is quite instrumental for the enzyme activation.