Design of carbonic anhydrase with improved thermostability for CO2 capture via molecular simulations

Chemical absorption of CO2 is the most widely used method to capture CO2. However, high cost and slow CO2 absorption rate severely hinder its commercial utilization. Human carbonic anhydrase II (hCA II) having rapid hydratase reaction rate can potentially overcome these obstacles but being highly unstable against harsh process conditions. To enhance thermostability, a novel CA was developed based on molecular simulations. Substituting residue Leu204 with Lys has a comparable hydratase activity as the wild type (WT) hCA II, 1.98 x 10(6) s(-1) for k(cat) and 2.36 x 10(8) M( -1)s(-1) for k(cat) /K-m. Importantly, the replacement of L204 K results in higher temperature resistance with 100 % retention at 45 degrees C and around 50 % at 55 degrees C while WT totally inactivates at 45 degrees C. Furthermore, L204 K is able to maintain its activity in the presence of anions and EDTA. The robustness and efficiency of this novel CA make it a competitive candidate for CO2 capture.