Novotná Pavlína, Králík František, Urbanová Marie
Department of Analytical Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic.
Department of Physics and Measurements, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic.
Biophys Chem. 2015 Oct;205:41-50. doi: 10.1016/j.bpc.2015.06.001. Epub 2015 Jun 4.
The structural formula of biologically important chiral pigments bilirubin and biliverdin differs only by one double bond. We showed that this results in dissimilar interactions with two models of membranes: cationic liposomes composed of 3β-[N-(N',N'-dimethylaminoethane)-carbamoyl]cholesterol and zwitterionic micelles from 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS). While the liposomes recognized the P-form of bilirubin, the micelles recognized its M-form. Both recognized the P-form of biliverdin. Our study also comprised ternary systems consisting of the pigments, model membranes and serum albumin (human and bovine). Bilirubin preferentially interacted with the albumins even in the presence of the liposomes. On the other hand, biliverdin preferred the liposomes. Remarkably, the presence of CHAPS completely changed the biliverdin binding to the protein. Because our study was oriented on different chiral interactions, a chiroptical method of electronic circular dichroism was chosen as the principal method to study our systems. As complementary methods, UV-vis absorption and fluorescence emission were used.
具有生物学重要性的手性色素胆红素和胆绿素的结构式仅相差一个双键。我们发现，这导致它们与两种膜模型的相互作用不同：由3β-[N-(N',N'-二甲基氨基乙烷)-氨基甲酰基]胆固醇组成的阳离子脂质体和由3-[(3-胆酰胺基丙基)二甲基铵]-1-丙烷磺酸盐（CHAPS）形成的两性离子胶束。脂质体识别胆红素的P型，而胶束识别其M型。两者都识别胆绿素的P型。我们的研究还包括由色素、模型膜和血清白蛋白（人源和牛源）组成的三元体系。即使存在脂质体，胆红素也优先与白蛋白相互作用。另一方面，胆绿素更倾向于脂质体。值得注意的是，CHAPS的存在完全改变了胆绿素与蛋白质的结合。由于我们的研究侧重于不同的手性相互作用，因此选择电子圆二色性的手性光学方法作为研究我们体系的主要方法。作为补充方法，使用了紫外-可见吸收和荧光发射。
