Sodium hexadecyl sulfate as an interfacial substance adjusting the adsorption of a protein on carbon nanotubes.
Carbon nanotubes (CNTs) were functionalized with sodium hexadecyl sulfate (SHS). The lysozyme adsorbed on the SHS-CNTs exhibited a higher activity than that immobilized on the nonfunctionalized CNTs. To explain the experimental results and explore the mechanism of lysozyme adsorption, large-scale molecular dynamics simulations have been performed for a four-component system, including lysozyme, SHS, CNTs in explicit water. It has been found that the assembled SHS molecules form a soft layer on the surface of CNTs. The interactions between lysozyme and SHS induce the rearrangement of SHS molecules, forming a saddle-like structure on the CNT surface. The saddle-like structure fits the shape of the lysozyme, and the active-site cleft of the lysozyme is exposed to the water phase. Whereas, for the lysozyme adsorbed on the nonfunctionalized CNT, due to the hydrophobic interactions, the active-site cleft of the enzyme tends to face the wall of the CNT. The results of this work demonstrate that the SHS molecules as the interfacial substance have a function of adjusting the lysozyme with an appropriate orientation, which is favorable for the lysozyme having a higher activity.
['Sun|Jian|J|', 'Du|Kun|K|', 'Fu|Li|L|', 'Gao|Jiang|J|', 'Zhang|Haiyang|H|', 'Feng|Wei|W|', 'Ji|Peijun|P|']
D000327:Adsorption D003198:Computer Simulation D019277:Entropy D009113:Muramidase D037742:Nanotubes, Carbon D013431:Sulfates D013501:Surface-Active Agents D014867:Water
sodium hexadecyl sulfate carbon nanotubes lysozyme molecular dynamics simulation