Zhdanov R I, Strazhevskaya N B, Jdanov A R, Bischoff G
V. N. Orekhovich Institute of Biomedical Chemistry, Russian Academy of Medical Sciences, 10, Pogodinskaya St., 119992 Moscow, Russia.
J Biomol Struct Dyn. 2002 Oct;20(2):231-42. doi: 10.1080/07391102.2002.10506839.
The interaction of synthetic polynucleotide double strands with a natural lipid, oleic acid, was examined in diluted aqueous solutions by circular dichroism spectra, UV-absorption measurements, and surface plasmon resonance biosensor investigations. The investigations were performed with defined double and triple stranded oligo- and polydeoxyribonucleotides. Whereas duplexes are influenced by oleic acid ligandation, which could not be removed by ethanol dialysis procedure, no binding occurs to triple stranded DNA. The spectroscopic results indicate that oleic acid shows molecular recognition to AT b.p. motifs by groove binding. GC tracts - in particular alternating d[G-C] motifs - are strongly influenced by ligand interaction up to a ratio of one molecule per two base pairs. Likewise, the spectroscopic and morphologic changes in the supramolecular association of the complexes after treatment occur even after dialysis procedure. This was monitored with scanning force microscopy (SFM) as well. Additionally, monolayers of biotinylated DNA duplexes were immobilized on a streptavidin sensor-layer for surface plasmon resonance (SPR) observations. Small portions of the ligand were injected in continuous flow. Loosely bound molecules were removed by washing procedure. Injections of sodium hydroxide denature the DNA, releasing the tightly bound effectors. The amount of tightly bound oleic acid molecules was determined at one molecule per 2-3 base pairs. As consequence, a new mechanism of regulation of gene expression at nuclear membrane or by lipids inside DNA double helix has to be discussed.
通过圆二色光谱、紫外吸收测量和表面等离子体共振生物传感器研究，在稀释的水溶液中研究了合成多核苷酸双链与天然脂质油酸的相互作用。研究使用了确定的双链和三链寡脱氧核糖核苷酸及多脱氧核糖核苷酸。双链体受油酸配位影响，乙醇透析法无法去除这种影响，而三链DNA不发生结合。光谱结果表明，油酸通过沟槽结合对AT碱基对基序表现出分子识别。GC序列——特别是交替的d[G-C]基序——在每两个碱基对一个分子的比例之前，受配体相互作用的影响很大。同样，处理后复合物超分子缔合中的光谱和形态变化即使在透析后也会发生。这也通过扫描力显微镜（SFM）进行了监测。此外，将生物素化DNA双链体的单层固定在链霉亲和素传感器层上进行表面等离子体共振（SPR）观察。将少量配体以连续流动的方式注入。通过洗涤程序去除松散结合的分子。注入氢氧化钠使DNA变性，释放紧密结合的效应物。确定紧密结合的油酸分子数量为每2至3个碱基对一个分子。因此，必须讨论一种在核膜处或DNA双螺旋内部由脂质调控基因表达的新机制。
