Zhang Yunzhi, Casabianca Leah B
Department of Chemistry , Clemson University , Clemson , South Carolina 29634 , United States.
J Phys Chem Lett. 2018 Dec 6;9(23):6921-6925. doi: 10.1021/acs.jpclett.8b02785. Epub 2018 Nov 28.
The interaction between individual amino acids and the surface of carboxylate-modified polystyrene nanoparticles in solution was studied using Saturation-Transfer Difference (STD)-Nuclear Magnetic Resonance (NMR). Individual amino acids were screened for nanoparticle binding using an STD-NMR experiment at a fixed saturation time, and STD buildup curves were measured for those amino acids that exhibited significant STD difference signals in the initial screening. The strongest STD effects were measured for protons of aromatic side chains, with relatively weaker effects observed for protons in long-chain aliphatic and positively charged side chains. This indicates that there are several modes of binding to these polystyrene nanoparticles: electrostatic attraction between the negatively charged surface of the carboxylate-modified polystyrene nanoparticle and positively charged amino acids, hydrophobic effects between long aliphatic side chains and the nanoparticle surface, and π-π interactions between aromatic amino acids and aromatic groups in styrene. This information can be used in future studies to predict and understand interactions between nanoparticle surfaces and specific amino acid residues in small peptides and proteins.
利用饱和转移差分（STD）-核磁共振（NMR）研究了溶液中单个氨基酸与羧酸盐修饰的聚苯乙烯纳米颗粒表面之间的相互作用。在固定的饱和时间下，使用STD-NMR实验筛选单个氨基酸与纳米颗粒的结合情况，并对那些在初始筛选中表现出显著STD差异信号的氨基酸测量STD积累曲线。对于芳香族侧链的质子，测量到的STD效应最强，而对于长链脂肪族和带正电荷侧链中的质子，观察到的效应相对较弱。这表明与这些聚苯乙烯纳米颗粒存在几种结合模式：羧酸盐修饰的聚苯乙烯纳米颗粒带负电荷的表面与带正电荷的氨基酸之间的静电吸引、长脂肪族侧链与纳米颗粒表面之间的疏水作用，以及芳香族氨基酸与苯乙烯中的芳香基团之间的π-π相互作用。这些信息可用于未来的研究，以预测和理解纳米颗粒表面与小肽和蛋白质中特定氨基酸残基之间的相互作用。
