In Silico Investigation of Potential Applications of Gamma Carbonic Anhydrases as Catalysts of CO Biomineralization Processes: A Visit to the Thermophilic Bacteria and .

Carbonic anhydrases (CAs) have been identified as ideal catalysts for CO sequestration. Here, we report the sequence and structural analyses as well as the molecular dynamics (MD) simulations of four γ-CAs from thermophilic bacteria. Three of these, , and originate from hydrothermal vents and one, HB8, from hot springs. Protein sequences were retrieved and aligned with previously characterized γ-CAs, revealing differences in the catalytic pocket residues. Further analysis of the structures following homology modeling revealed a hydrophobic patch in the catalytic pocket, presumed important for CO binding. Monitoring of proton shuttling residue His69 ( γ-CA numbering) during MD simulations of and 's γ-CAs (γ-PhCA and γ-PmCA) showed a different behavior to that observed in the γ-CA of which periodically coordinates Zn. This work also involved the search for hotspot residues that contribute to interface stability. Some of these residues were further identified as key in protein communication via metric of dynamic residue network analysis. γ-CA showed marginally lower thermostability compared to the other three γ-CA proteins with an increase in conformations visited at high temperatures being observed. Hydrogen bond analysis revealed important interactions, some unique and others common in all γ-CAs, which contribute to interface formation and thermostability. The seemingly thermostable γ-CA from strangely showed increased unsynchronized residue motions at 423 K. γ-PhCA and γ-PmCA were, however, preliminarily considered suitable as prospective thermostable CO sequestration agents.