title: Probing immobilization mechanism of alpha-chymotrypsin onto carbon nanotube in organic media by molecular dynamics simulation.
abstract: The enzyme immobilization has been adopted to enhance the activity and stability of enzymes in non-aqueous enzymatic catalysis. However, the activation and stabilization mechanism has been poorly understood on experiments. Thus, we used molecular dynamics simulation to study the adsorption of α-chymotrypsin (α-ChT) on carbon nanotube (CNT) in aqueous solution and heptane media. The results indicate that α-ChT has stronger affinity with CNT in aqueous solution than in heptane media, as confirmed by more adsorption atoms, larger contact area and higher binding free energies. Although the immobilization causes significant structure deviations from the crystal one, no significant changes in secondary structure of the enzyme upon adsorption are observed in the two media. Different from aqueous solution, the stabilization effects on some local regions far from the surface of CNT were observed in heptane media, in particular for S1 pocket, which should contribute to the preservation of specificity reported by experiments. Also, CNT displays to some extent stabilization role in retaining the catalytic H-bond network of the active site in heptane media, which should be associated with the enhanced activity of enzymes. The observations from the work can provide valuable information for improving the catalytic properties of enzymes in non-aqueous media.
authors: Faculty of Chemistry, Sichuan University, Chengdu 610064, People's Republic of China.
authors: Liyun
authors: L
authors: Zhang
authors: Faculty of Chemistry, Sichuan University, Chengdu 610064, People's Republic of China.
authors: Xiuchan
authors: X
authors: Xiao
authors: College of Management, Southwest University for Nationalities, Chengdu 610041, People's Republic of China.
authors: Yuan
authors: Y
authors: Yuan
authors: Faculty of Chemistry, Sichuan University, Chengdu 610064, People's Republic of China.
authors: Yanzhi
authors: Y
authors: Guo
authors: Faculty of Chemistry, Sichuan University, Chengdu 610064, People's Republic of China.
authors: Menglong
authors: M
authors: Li
authors: Faculty of Chemistry, Sichuan University, Chengdu 610064, People's Republic of China.
authors: Xuemei
authors: X
authors: Pu
mesh_terms: D000327:Adsorption; D002384:Catalysis; D020134:Catalytic Domain; D002918:Chymotrypsin / Q000737:chemistry*; D004800:Enzymes, Immobilized; D006860:Hydrogen Bonding; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary
chemical_list: D004800:Enzymes, Immobilized; D037742:Nanotubes, Carbon; D002918:Chymotrypsin; C117608:alpha-chymotrypsin