Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
Nucleic Acids Res. 2011 Nov 1;39(20):8891-900. doi: 10.1093/nar/gkr568. Epub 2011 Jul 23.
The interaction between single-stranded RNAs and liposomes was studied using UV, Fourier Transform Infrared spectroscopy (FTIR) and Circular Dichroism spectroscopy (CD). The effect of the surface characteristics of liposomes, which were composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and modified with cholesterol (Ch) or 1,2-dioleoyl-3-trimethylammonium propane (DOTAP), on the liposome-RNA interaction was investigated. The fluorescence of 6-(p-toluidino)naphthalene-2-sulfonate (TNS) embedded in the liposome surface (ε = 30-40) was decreased in the presence of tRNA, suggesting that single-stranded tRNA could bind onto the liposome. The dehydration of -PO₂⁻-, guanine (G) and cytosine (C) of tRNA molecules in the presence of liposomes suggested both an electrostatic interaction (phosphate backbone of tRNA and trimethylammonium group of POPC, DOTAP) and a hydrophobic interaction (guanine or cytosine of tRNA and aliphatic tail of lipid). The tRNA conformation on the liposome was determined by CD spectroscopy. POPC/Ch (70/30) maintained tRNA conformation without any denaturation, while POPC/DOTAP(70/30) drastically denatured it. The mRNA translation was evaluated in an Escherichia coli cell-free translation system. POPC/Ch(70/30) enhanced expression of green fluorescent protein (GFP) (116%) while POPC/DOTAP(70/30) inhibited (37%), suggesting that the conformation of RNAs was closely related to the translation efficiency. Therefore, single-stranded RNAs could bind to liposomal membranes through electrostatic and hydrophobic attraction, after which conformational changes were induced depending on the liposome characteristics.
使用紫外光谱、傅里叶变换红外光谱（FTIR）和圆二色光谱（CD）研究了单链 RNA 与脂质体的相互作用。研究了由 1-棕榈酰基-2-油酰基-sn-甘油-3-磷酸胆碱（POPC）组成的脂质体的表面特性对脂质体-RNA 相互作用的影响，这些脂质体经过胆固醇（Ch）或 1,2-二油酰基-3-三甲铵丙烷（DOTAP）修饰。嵌入脂质体表面的 6-（对甲苯亚氨基）-2-萘磺酸盐（TNS）的荧光（ε = 30-40）在 tRNA 存在下降低，表明单链 tRNA 可以结合到脂质体上。在脂质体存在下 tRNA 分子的 -PO₂⁻、鸟嘌呤（G）和胞嘧啶（C）的去水作用表明存在静电相互作用（tRNA 的磷酸骨架和 POPC、DOTAP 的三甲铵基团）和疏水相互作用（tRNA 的鸟嘌呤或胞嘧啶和脂质的脂肪链）。CD 光谱法确定了 tRNA 在脂质体上的构象。POPC/Ch（70/30）保持 tRNA 构象而无任何变性，而 POPC/DOTAP（70/30）则使其严重变性。在大肠杆菌无细胞翻译系统中评估了 mRNA 翻译。POPC/Ch（70/30）增强了绿色荧光蛋白（GFP）的表达（116%），而 POPC/DOTAP（70/30）则抑制了表达（37%），表明 RNA 的构象与翻译效率密切相关。因此，单链 RNA 可以通过静电和疏水吸引结合到脂质体膜上，之后根据脂质体的特性诱导构象变化。
