Molecular property and functional control of chaperone-like polymer

蛋白质聚集引起的不可逆变性是蛋白质结构研究中的一个重要问题。分子伴侣是热休克蛋白的成员，通过弱蛋白整合阻止蛋白在体内聚集。磷脂聚合物（MPC聚合物）也有弱相互作用的蛋白质，我们使用这些聚合物作为人工分子伴侣。我们设计了几种MPC共聚物，并对它们的类伴侣活性进行了筛选。研究了β-半乳糖苷酶、苹果酸脱氢酶、MHCⅱ类酶、荧光素酶（GFP）和罗丹斯酶（rhodanese）的再折叠活性。与甲基丙烯酸丁酯共聚物（PMB聚合物）的共聚物对这些蛋白质的再折叠表现出良好的性能。体外蛋白质合成是实现这一目标的有效方法之一，但该方法存在产率低的缺点。为了构建高效的体外蛋白质合成体系，研究了PMB聚合物的合成效果。虽然PMB聚合物具有类似伴侣的活性，但该聚合物并没有提高罗丹斯在体外蛋白质合成中的产率。另一种新的MPC聚合物的设计对于高效的体外蛋白质合成系统是必要的。此外，我们研究了MPC共聚物对胰岛素淀粉样纤维形成的影响。我们发现亲水共聚物加速了淀粉样蛋白的形成速度，而疏水共聚物则减少了淀粉样蛋白纤维的总量。但到目前为止，MPC共聚物还没有足够的能力来控制淀粉样蛋白纤维的结构。我们将通过共聚比和分子量的排列来提高MPC共聚物的功能性能。

The irreversible protein denaturation due to the aggregation is serious problem in the research of protein structure. Molecular chaperones, member of heat shock protein, prevent the protein aggregate in vivo through the weak protein integration. It has been shown that phospholipid polymers (MPC polymer) also weakly interact proteins, and we used these polymers as the artificial molecular chaperone. We have design several MPC copolymers, and screened by there chaperone-like activity. The activity for the refolding of β-galactosidase, malate dehydrogenase, MHC Class II, luciferase GFP and rhodanese have been examined. The copolymer with butylmethacrylate (PMB polymer) showed high performance for the refolding of these proteins.The in vitro protein synthesis is one of the effective methods for this purpose, but this method has weak point of the low yield. To construct a highly efficient in vitro protein synthesis system, the effects PMB polymer were examined. Although PMB polymer showed chaperone-like activity, the yield of rhodanese in the in vitro protein synthesis was not enhanced by this polymers. Another new design of the MPC polymer is necessary for the efficient in vitro protein synthesis system. Furthermore, we examined the effect of MPC copolymers on the amyloid fibril formation of insulin. We found that hydrophilic copolymers accelerated the amyloid formation rate, and the hydrophobic copolymers reduced the total amount of amyloid fibril. But so far, MPC copolymers don't have sufficient ability to control amyloid fibril structure. We will improve the functional capability of MPC copolymer by the arrangement of copolymerization ratio and molecular weight.