Screening Mutational Sites That Enhance Protein Thermostability By High Temperature Molecular Dynamics Method

Protein is organism function performer and is also a important research object in life sciences. All life action cannot go without the participation of protein. Each kind of protein having a certain optimum temperature scope to display its function, and protein activity will be influenced if the temperature is higher than or lower than this temperature range, or even will be deactivated. But now, in food, chemical industry, molecular design, biomedicine and so on, proteins that can maintain its original structure and function under high temperature are needed; therefore, to enhance protein's thermostability and understand the mechanism that the protein displays its function, discover the key factors that influenced protein's thermostability was not only a scientific problem, but has played a more and more vital role in people's daily life, attracting more and more scientists to spend massive time and energy to the protein thermostability research.Residue mutation is an efficient method to enhance protein's thermostability. To predict the mutational sites, numerous successes have been achieved through protein engineering method, for instance the rational design, random mutagenesis and consensus method. But, how to choose mutational sites still haven't been completely solved at present. The efficiency and the screening validity also need to further enhance.For this purpose, we use the high temperature dynamics method, considering the interresidue energy, the protein structure as well as the structure along with temperature information, to screen mutational sites that can enhance protein's thermostability. We chose 4 proteins as our research material from the ProTherm database under certain conditions. The proteins are: 1csp ,1qqv, 1rop and 1pga. Take 1csp as the example, we did dynamics simulation at Tm, Tm+50k, Tm+100k, Tm+150k temperature, we carried out the statistical analysis to the analogue result, and selected a suitable temperature in which dynamics simulation was made. Then we made dynamics simulation under this temperature to the three other proteins. According to the influence factors as well as these factors'contribution to protein's thermostability, we did a preliminary screening to the protein residue first; for the suited residues, we further analyzed the distance between the residues change along with the time, then eliminated the conservative residues, the left are our final results.Our method needs fewer data, easy to realize, and the efficiency is high, and also has the very good application value. The findings of this article indicated that the electrostatic effect and the hydrophobic effect maybe the most important factors that affect protein's thermostability.