含硫氨基酸与本征及缺陷石墨烯表面的相互作用

半胱氨酸及蛋氨酸是人体的两种含硫氨基酸,在生物活性中发挥着巨大的作用.本研究采用密度泛函理论方法对以上两种氨基酸在本征及缺陷石墨烯表面的吸附机理进行了详细研究.主要考虑了两种吸附体系:半胱氨酸及蛋氨酸平躺在两种石墨烯表面;两种氨基酸垂直地放置于两种石墨烯表面,且含硫的基团靠近表面.研究结果表明,半胱氨酸及蛋氨酸初始构型对它们之间的相互作用有一定的影响.两种氨基酸平躺时有较大的吸附能.此外,吸附能的结果显示两种氨基酸可以更好的与缺陷石墨烯表面紧密结合.同时,蛋氨酸与本征及缺陷石墨烯相互作用均大于半胱氨酸与本征及缺陷石墨烯相互作用.模拟结果有望为含硫氨基酸的石墨烯传感器提供有用的指导.

Study on the Interactions of Sulfur-Containing Amino Acids with the Pristine and Defective Graphene Surfaces

The cysteine and methionine are two kinds of sulfur-containing amino acids in human body, which play an important role in biological activities. The adsorption mechanism of two amino acids on the pristine and defective graphene surfaces was studied in detail using density functional theory (DFT) method. Two adsorption systems are mainly considered: two amino acids lie flat on the pristine and defective graphene surfaces; two amino acids are vertically placed on the pristine and defective graphene surfaces, and the sulfur-containing group is close to the surface. The results showed that the initial configurations of cysteine and methionine have some influence on their interactions. There are high adsorption energies when two amino acids lie flat on pristine and defective graphene surfaces. In addition, the adsorption energy showed that two types of amino acids can better bind to the defective graphene surfaces. At the same time, the results indicated that interactions of methionine with the pristine and defective graphenes are greater than those of cysteine with the pristine and defective graphenes. The simulation results are expected to provide useful guidance for the graphene-based sensor on the sulfur-containing amino acids.