Clay-nucleic acid complexes: Characteristics and Implications for the preservation of genetic material in primeval habitats
Clay-nucleic acid complexes: Characteristics and Implications for the preservation of genetic material in primeval habitats
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DOI：
10.1023/a:1006557832574
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发表时间：
1999-05-01
影响因子：
2
通讯作者：
Gallori, E
中科院分区：
文献类型：
--
作者：
Franchi, M;Bramanti, E;Gallori, E
研究了三种核酸：染色体DNA、超螺旋质粒DNA和25S rRNA在粘土矿物蒙脱石(M)和高岭石(K)上的平衡吸附。接触时间 90 分钟后，核酸在粘土上的吸附迅速且最大。染色体 DNA 的吸附程度比质粒 DNA 和 RNA 更大，并且 M 上的吸附也比 K 上的吸附更大。吸附等温线为 L 型，除了 M 上吸附的染色体 DNA 外，所有复合物均达到平台。为了确定核酸吸附在粘土矿物上的位置以及相互作用的性质，通过 X 射线衍射 (X-RD)、电子显微镜和傅里叶变换红外对复合物进行了研究（FT-IR）光谱。 X-RD 显示核酸没有渗透粘土，表明吸附主要发生在粘土颗粒的外表面，电子显微镜观察也表明这一点。与粘土紧密结合的核酸复合物的 FT-IR 光谱显示出吸收带，表明核酸状态由于其吸附在粘土上而发生变化。获得的数据表明，粘土-核酸复合物的形成可能在原始栖息地遗传物质的保存中发挥重要作用。
The equilibrium adsorption of three nucleic acids: chromosomal DNA, supercoiled plasmid DNA, and 25S rRNA, on the clay minerals, montmorillonite (M) and kaolinite (K), were studied. Adsorption of the nucleic acid on the clays was rapid and maximal after 90 min of contact time. Chromosomal DNA was adsorbed to a greater extent than plasmid DNA and RNA, and the adsorption was also greater on M than on K. Adsorption isotherms were of the L type, and a plateau was reached with all the complexes, with the exception of chromosomal DNA adsorbed on M. To determine where nucleic acids are adsorbed on clay minerals and the nature of the interaction, complexes were studied by X-ray diffraction (X-RD), electron microscopy, and Fourier transform infrared (FT-IR) spectroscopy. X-RD showed that nucleic acids did not penetrate the clay, indicating that the adsorption occurred primarily on the external surfaces of clay particles, as also suggested by electron microscopy observations. FT-IR spectra of clay-tightly bound nucleic acid complexes showed absorption bands that indicate a variation of the nucleic acids status as a consequence of their adsorption on clay. Data obtained suggested that the formation of clay-nucleic acid complex could have an important role in the preservation of genetic material in primeval habitats.