Study on the Discrimination of Thermophilic and Mesophilic Proteins Based on Dipeptide Composition

In this study, the dipeptide composition of 3 216 thermophilic and 4 007 mesophilic protein sequences was systematically analyzed. It was found that the thermophilic proteins contained larger number of dipeptides such as EE, EK, KE, VE, EI, KI, EV, KK, VK and IE, and smaller number of dipeptides such as AA, LL, LA, AL, QA, QL, AQ, LT, TL and EQ. Hence, a statistical method was developed for the discrimination of thermophilic and mesophilic proteins. The method that was developed picked up the thermophilic proteins with an accuracy of 94.0 % and 89 %, respectively, for the testing sets of 382 and 73 thermophilic proteins. The accuracy for mesophilic proteins was 85.2 % and 89 %, respectively, for the testing sets of 325 and 73 mesophilic proteins. The influence of specific dipeptides on discrimination was also discussed.