Pinto Maria F V, Morán M Carmen, Miguel M Graça, Lindman Björn, Jurado Amália S, Pais Alberto A C C
Chemistry Department, Coimbra University, Rua Larga, Coimbra, Portugal.
Biomacromolecules. 2009 Jun 8;10(6):1319-23. doi: 10.1021/bm900211j.
This work addresses the influence of solution inhomogeneity on conformation, aggregation, and coil/globule and bundle/single chain coexistence of T4 DNA molecules. The inhomogeneity is induced by mixing two solutions containing, respectively, protamine and DNA, with different relative concentrations, but aiming at producing the same final concentrations. The study was conducted by means of fluorescence microscopy (FM), complemented with scanning electron microscopy (SEM). It is shown that the degree of precipitation, the structures formed, and the relative population of compacted and unfolded structures are highly dependent on the method of preparation of the mixtures that contain the DNA/protamine complexes. Most of the structures reported in the literature, that is, overcharged/undercharged globules, toroids, chains internally segregated, and bundles composed of several chains were observed in our different mixtures of fixed final concentration.
这项工作研究了溶液不均匀性对T4 DNA分子的构象、聚集以及线圈/球状体和束/单链共存的影响。这种不均匀性是通过混合两种分别含有鱼精蛋白和DNA的溶液诱导产生的，两种溶液的相对浓度不同，但最终目标是产生相同的最终浓度。该研究通过荧光显微镜（FM）进行，并辅以扫描电子显微镜（SEM）。结果表明，沉淀程度、形成的结构以及紧密结构和未折叠结构的相对比例高度依赖于含有DNA/鱼精蛋白复合物的混合物的制备方法。在我们固定最终浓度的不同混合物中观察到了文献中报道的大多数结构，即过电荷/欠电荷球状体、环面、内部隔离的链以及由几条链组成的束。
