Zimbone Massimo, Baeri Pietro, Barcellona Maria Luisa, Li Volti Giovanni, Bonaventura Gabriele, Viscuso Orazio
Dipartimento di Fisica e Astronomia, Università di Catania. 6, Viale A. Doria, I-95125 Catania, Italy.
Int J Biol Macromol. 2009 Oct 1;45(3):242-7. doi: 10.1016/j.ijbiomac.2009.05.009. Epub 2009 May 29.
This work reports light scattering measurements on DNA in aqueous solutions (100mM NaCl, 1mM EDTA and 10mM Tris-HCl buffer, pH 7.8) over a wide range of molecular weights (10(2)-10(5) base pairs) and shows that, in the above standard solvent, shorter chains (<10(4) base pairs) behave as a "wormlike chain" and their diffusion coefficients as obtained by dynamic light scattering measurements, confirm the prediction of standard wormlike model, whilst longer chains (>10(4) base pairs) behave in a different manner. Dynamic and static light scattering and SEM analysis indicate that DNA molecules 10(5) base pairs long, condense into compact structures in our solvent conditions. Calculations done using a wormlike model are also presented and discussed in comparison both to our experimental data and to other data reported in the literature.
这项工作报道了在一系列广泛分子量（10² - 10⁵碱基对）的DNA水溶液（100mM NaCl、1mM EDTA和10mM Tris-HCl缓冲液，pH 7.8）中的光散射测量结果，表明在上述标准溶剂中，较短的链（<10⁴碱基对）表现为“蠕虫状链”，通过动态光散射测量获得的它们的扩散系数证实了标准蠕虫状模型的预测，而较长的链（>10⁴碱基对）表现方式不同。动态和静态光散射以及扫描电子显微镜分析表明，10⁵碱基对长的DNA分子在我们的溶剂条件下凝聚成紧密结构。还展示了使用蠕虫状模型进行的计算，并将其与我们的实验数据以及文献中报道的其他数据进行了比较和讨论。
