Department of Chemistry, University of Birjand, Birjand, Iran.
Sci Rep. 2022 Jul 1;12(1):11156. doi: 10.1038/s41598-022-13738-5.
Free amino acids represent a category of different biomolecules in the blood plasma, which bond together to make up larger organic molecules such as peptides and proteins. Their interactions with biocompatible nanoparticles are especially important for plasma-related biomedical applications. Among the various nanomaterials, the applications of carbon and boron nitride-based nanotubes/nanosheets have shown a huge increase in recent years. The effect of molecular polarity on the interaction between a boron nitride nanosheet (BNNS) and amino acids is investigated with quantum mechanical calculations by density functional theory (DFT), classical MD simulations, and well-tempered metadynamics simulations. Four representative amino acids, namely, alanine (Ala), a nonpolar amino acid, and aspartic acid (Asp), lysine (Lys) and serine (Ser), three polar amino acids are considered for their interactions with BNNS. In DFT calculations, the values of the adsorption energies for Lys-BNNS and Ser-BNNS complexes are - 48.32 and - 32.89 kJ/mol, respectively, which are more stable than the other cases. Besides, the adsorption energy calculated confirms the exergonic reactions for all investigated systems; it implied that the interaction is favorable electronically. The MD results show that the LYS molecules have a higher attraction toward BNNS because of its alkane tail in its side chain, and the ASP revealed the repulsion force originating from its COO- group. All the results are confirmed by free energy analyzes in which the LYS showed the highest adsorption free energy at a relatively farther distance than other complexes. In fact, our results revealed the contribution of functional groups and backbone of the amino acids in the adsorption or repulsion features of the studied systems.
游离氨基酸是血浆中不同生物分子的一类，它们结合在一起形成较大的有机分子，如肽和蛋白质。它们与生物相容的纳米粒子的相互作用对于与血浆相关的生物医学应用尤为重要。在各种纳米材料中，碳和氮化硼基纳米管/纳米片的应用近年来有了巨大的增长。本研究通过密度泛函理论（DFT）、经典分子动力学（MD）模拟和调谐经验动力学（metadynamics）模拟的量子力学计算，研究了分子极性对氮化硼纳米片（BNNS）与氨基酸之间相互作用的影响。考虑了四种代表性的氨基酸，即丙氨酸（Ala）、非极性氨基酸和天冬氨酸（Asp）、赖氨酸（Lys）和丝氨酸（Ser），它们与 BNNS 相互作用。在 DFT 计算中，Lys-BNNS 和 Ser-BNNS 复合物的吸附能分别为-48.32 和-32.89 kJ/mol，这比其他情况更稳定。此外，计算出的吸附能证实了所有被研究系统都是放热反应；这意味着相互作用在电子上是有利的。MD 结果表明，由于其侧链中的烷烃尾巴，LYS 分子对 BNNS 具有更高的吸引力，而 ASP 则显示出源于其 COO-基团的排斥力。所有结果都通过自由能分析得到证实，其中 LYS 显示出比其他复合物更高的吸附自由能，在相对较远的距离。事实上，我们的结果揭示了氨基酸的官能团和骨架在研究系统的吸附或排斥特征中的贡献。
