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Supramolecular Association Impacts Biomolecule Adsorption onto Goethite
Environmental Science & Technology ( IF 11.4 ) Pub Date : 2018-03-14 00:00:00 , DOI: 10.1021/acs.est.7b06173
Michael P. Schmidt 1 , Carmen Enid Martínez 1
Affiliation  

Formation of biomolecule-rich supramolecular complexes in dissolved organic matter (DOM) and subsequent adsorption onto minerals is important for the development of mineral-stabilized organic matter, yet the impact of supramolecular association on interfacial behavior is seldom studied. A series of supramolecular complexes of model biomolecules (deoxyribonucleic acid (DNA) and bovine serum albumin (BSA)) are synthesized, characterized, and adsorbed onto goethite. Complexes represent 0.1 mg/mL DNA mixed with BSA concentrations from 0.05 to 0.5 mg/mL in 5 mM KCl at pH = 5.0. Circular dichroism demonstrates strong binding between DNA and BSA, with DNA saturation when (BSA) ≈ 0.4 mg/mL. Dynamic light scattering and electrophoretic mobility measurements suggest DNA−BSA binding reduces DNA–DNA electrostatic repulsion. Spectroscopic studies of DNA/BSA complex adsorption show complexation hinders coordination of DNA phosphodiester groups with goethite. Increasing BSA (≤0.4 mg/mL) in DNA/BSA complexes enhances DNA adsorption, due to reduced repulsion between adsorbed DNA helices. When (BSA) > 0.4 mg/mL, however, DNA adsorption is decreased. We hypothesize this results from blocking of surface sites by fast adsorption of BSA loosely associated with DNA/BSA complexes. We posit an additional mechanism describing multilayered architecture formation of organo-mineral associations in soil, suggesting solution interactions may represent an overlooked factor when considering mineral retention of DOM.

中文翻译:

超分子缔合影响生物分子在针铁矿上的吸附

在溶解的有机物(DOM)中形成富含生物分子的超分子复合物并随后吸附到矿物上对于矿物稳定的有机物的发展很重要,但是很少研究超分子缔合对界面行为的影响。合成,表征并吸附在针铁矿上的一系列模型生物分子的超分子复合物(脱氧核糖核酸(DNA)和牛血清白蛋白(BSA))。复合物代表0.1 mg / mL DNA与5 mM KCl中pH = 5.0的BSA浓度从0.05到0.5 mg / mL混合。圆二色性表明DNA和BSA之间有很强的结合力,当(BSA)≈0.4 mg / mL时,DNA饱和。动态光散射和电泳迁移率测量表明,DNA-BSA的结合减少了DNA-DNA的静电排斥。DNA / BSA络合物吸附的光谱研究表明,络合物阻碍了DNA磷酸二酯基与针铁矿的配位。由于吸附的DNA螺旋之间的排斥力降低,DNA / BSA复合物中的BSA(≤0.4mg / mL)增加可增强DNA吸附。但是,当(BSA)> 0.4 mg / mL时,DNA吸附会降低。我们假设这是由于与DNA / BSA复合物松散结合的BSA的快速吸附而导致表面位点封闭的结果。我们提出了描述土壤中有机-矿物质缔合的多层结构形成的另一种机制,这表明当考虑DOM的矿物保留时,溶液相互作用可能是一个被忽略的因素。由于减少了吸附的DNA螺旋之间的排斥力。但是,当(BSA)> 0.4 mg / mL时,DNA吸附会降低。我们假设这是由于与DNA / BSA复合物松散结合的BSA的快速吸附而导致表面位点封闭的结果。我们提出了描述土壤中有机-矿物质缔合的多层结构形成的另一种机制,这表明当考虑DOM的矿物保留时,溶液相互作用可能是一个被忽略的因素。由于减少了吸附的DNA螺旋之间的排斥力。但是,当(BSA)> 0.4 mg / mL时,DNA吸附会降低。我们假设这是由于与DNA / BSA复合物松散结合的BSA的快速吸附而导致表面位点封闭的结果。我们提出了描述土壤中有机-矿物质缔合的多层结构形成的另一种机制,这表明当考虑DOM的矿物保留时,溶液相互作用可能是一个被忽略的因素。
更新日期:2018-03-14
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