Investigation on bioactive protection of the amino acids derived from LEA protein on insulin by molecular simulation

Abstract

Nowadays heat-sensitive protein medicines are increasingly showing their importance in the treatment of various diseases. Their popularisation and application are meeting a great challenge because of their heat lability. In this study, human insulin as a heat-sensitive protein medicine and 66 amino acids derived from a Group 3 late embryogenesis abundant protein fragment as a complex bioactive protectant, were chosen to be investigated to determine whether these amino acids can be used to protect the insulin from denaturation due to drying. The experiments were carried out by using a replica exchange molecular dynamics (REMD) simulation and GROMACS software with Gromos96 (53a6) force field. The REMD results indicate that those amino acids can effectively prevent the reversal between hydrophilic and hydrophobic surface. Both the configurations and secondary structures of the protected insulin were preserved very well. The H-bonding and electrostatic interactions between the insulin and the protectant play key roles in the bioactive protection of insulin. These results agree well with the water replacement hypothesis. All the results prove that these amino acids are a perfect bioactive protectant for heat-sensitive protein medicines.

Keywords::

• amino acids derived from late embryogenesis abundant protein
• human insulin
• drying
• bioactive protection
• replica exchange molecular dynamics simulation

Acknowledgements

This project was supported by the National Natural Science Foundation of China (Grant No. 51076108), Key Disciplines Program of Shanghai, China (Grant Nos. T0503 and P0502), the Innovation Funds for International Cooperation of the Shanghai Committee of Science and Technology, China (Grant No. 12430702000) and the Natural Science Foundation of Shanghai, China (Grant No. 12ZR1420400) as well as Alliance Program in Shanghai, China. We are grateful to Prof. Alan Tunnacliffe at University of Cambridge and to Prof. Chen Chenglung at National Sun Yat-Sen University for their insights into the protection mechanisms of LEA protein on insulin.