Journal:JBSD:22

In order to investigate the thermal stability of <scene name='Journal:JBSD:22/Cv/9'>tteRBP</scene> (<span style="color:violet;background-color:black;font-weight:bold;">crystal structure ([[2ioy]]) is in violet</span>, <font color='magenta'><b>tteRBP under the room temperature (300 K) is in magenta</b></font>, <font color='darkmagenta'><b>tteRBP under the optimal activity temperature (375 K) is in darkmagenta</b></font>) and <scene name='Journal:JBSD:22/Cv/14'>ecRBP</scene> (<span style="color:yellow;background-color:black;font-weight:bold;">crystal structure ([[2dri]]) is in yellow</span>, <span style="color:orange;background-color:black;font-weight:bold;">ecRBP under the room temperature (300 K) is in orange</span>, <span style="color:chocolate;background-color:black;font-weight:bold;">ecRBP under the optimal activity temperature (329 K) is in chocolate</span>) molecular dynamics simulations were performed for investigating the dynamics changes of the two proteins. The results show that the overall structures of the ecRBP and tteRBP are well maintained at the two temperatures, respectively. The radius of gyration, solvent accessible surface area, salt bridges, side-chain interactions and hydrogen bonds of the two proteins are almost unchanged at the different temperatures, their conformations also have no obvious changes, moreover, the RMSIP reflect that the overall motion of tteRBP or ecRBP move along the same direction of the essential fluctuations at the different temperatures, respectively. The further analysis shows that the tteRBP and ecRBP both have strong side-chain interactions to maintain structural stability at the high temperatures, and they have different patterns of the intramolecular motion and flexibility at the two temperatures. At room temperature and the optimal activity temperature, the <scene name='Journal:JBSD:22/Cv/10'>tteRBP has higher flexibility</scene> and <scene name='Journal:JBSD:22/Cv/15'>more high flexible regions</scene> (<font color='darkmagenta'><b>tteRBP under the optimal activity temperature (375 K) is in darkmagenta</b></font> with <span style="color:green;background-color:black;font-weight:bold;">highly flexible regions colored in green</span> and <span style="color:chocolate;background-color:black;font-weight:bold;">ecRBP under the optimal activity temperature (329 K) is in chocolate</span> with <span style="color:lime;background-color:black;font-weight:bold;">highly flexible regions colored in lime</span>) than the ecRBP. These are the most differences between tteRBP and ecRBP. So the higher flexibility of tteRBP 375 K has more advantageous to maintain overall structure stability and adapt to high temperature by the fine-tune structure with higher flexibility. According to article of Matthew ''et al''., (2008)<ref name="Matthew">PMID:18373848</ref> we can conclude that the strong side-chain interactions and flexibility of backbone both are the key factors to maintain thermal stability of the two proteins.