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Biopharmaceuticals are proteins with a crucial role in the treatment of many diseases. However, these protein medicines are often thermally labile and therefore unsuitable for long-term application and storage, as they tend to lose their activity under ambient conditions. Desiccation is one approach to improving protein stability, but the drying process itself can cause irreversible damage. In the current study, insulin was chosen as an example of a thermally sensitive biopharmaceutical to investigate whether the disaccharide, trehalose, can prevent loss of structural integrity due to drying. The experiment was performed using replica exchange molecular simulation and Gromacs software with a Gromos96 (53a6) force field. The results indicate that trehalose preserves the bioactive structure of insulin during drying, consistent with the use of trehalose as a protectant for thermally sensitive biopharmaceuticals. For instance, at the water content of 1.77%, insulin without any protectants yields the highest RMSD value as 0.451 nm, then the RMSD of insulin in presence of trehalose only ca. 0.100 nm.

Heat sensitive protein medicines are increasingly exhibiting their critical importance on treatment of various diseases at present. But their popularization and application meet a great challenge because of their heat instability. In the present study, insulin was taken as a heat sensitive protein medicine and amino acid as bio-protective agent in order to investigate if these amino acids can protect the insulin from losing its bioactivity due to desiccation. The experiment was performed by using replica exchange molecular simulation (REMD) method and Gromacs software with Gromos96 (53a6) force field. The REMD results indicated that these amino acids could protect the bioactive structure of insulin during desiccation. The configurations of the protected insulin were preserved very well. Those results proved that amino acid is a kind of good bioactive protective agent for the heat sensitive protein medicines.

Nowadays various protein medicines are increasingly playing significant roles in the treatment of many diseases, but the bioactive structures of such kinds of protein medicines are unstable because they are heat sensitive. Therefore, it is very important to explore a protective method and to explain the protective mechanism of protein medicines. In the present research, insulin was chosen as a heat-sensitive protein medicine, and a Group 3 late embryogenesis abundant (LEA) protein was chosen as its bioactive protectant during desiccation. The results of replica exchange molecular dynamics simulation suggest that comparing with insulin without any protection, the bioactive 3D structure and secondary structure of the insulin protected by LEA protein were preserved very well. All analyzing results proved that the LEA protein was a good bioactive protectant for heat sensitive protein medicines.

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. [ABSTRACT FROM AUTHOR]

Nowadays various protein medicines are increasingly playing a key role on treatment of many diseases, while the bioactivity of such kinds of protein medicines is unstable because of their heat sensitivity. In order to explore a protective method and to explain the protective mechanism of protein medicines, the bioactive protection of the late embryogenesis abundant (LEA) protein to insulin was researched by molecular dynamics simulation. The results suggest that LEA proteins preserve the native structure of the insulin well. Compared with the desiccated insulin without any protection, the structure of insulin protected by LEA protein have smaller values, more centralised configurational space, lower free energies and structural cluster more closer to the native structure. All the above results prove that the LEA protein does protect the bioactivity of insulin during desiccation. The LEA protein is a perfect bioactive protectant for heat-sensitive protein medicines. Such LEA proteins can match the shape of insulin and form multisite binding interaction with insulin. [ABSTRACT FROM AUTHOR]

Abstract Ionic liquids (ILs) have been used as a kind of green solvents trying to preserve protein drugs for many years. However, the protective mechanism of ILs on protein drugs is still unclear, which limits their application. For this reason, a molecular dynamic simulation (MD) was used to investigate the structural stability of insulin in 17 ILs solvents, including 10 pure and 7 hydrated ILs systems. The results of molecular interaction between insulin and ILs indicate insulin is stable in pure ILs with lower hydrogen bond basicity and shorter alkyl chain. And while water content is less than 25.00%, the hydrated ILs also are favorable for protein conservation. Moreover, the micro-DSC experimental results prove that the thermal stability of insulin in hydrated [C 2 mim][OAC] also support the results of MD simulation. So it can be seen that the ILs with lower hydrogen bond basicity and shorter alkyl chain usually have a protective effect on protein, and the MD simulation provides a new and extraordinary method for screening the protective ILs. Highlights • The ILs which only have weak or no H-bond with protein are a protective solvent. • The protection of ILs on protein is derived from the electrostatic interaction. • MD simulation provides an extraordinary method for screening the protective ILs. [ABSTRACT FROM AUTHOR]