Cold adaptation strategy of psychrophilic bacteria: an in-silico analysis of isocitrate dehydrogenase

Abstract

Non-specific electrostatics is crucial for structure and stability; recently, it has been argued that psychrophilic proteins may also utilize specific electrostatic interactions. Do psychrophilic proteins increase the number of salt bridges for cold adaptation? Are there any changes that occur in their sequence, which helps them to adapt in an extreme environment? Do intra-protein interactions affect their stability? Is there any special type of intra-protein interaction present in psychrophilic protein structure? This study will give all those answers. Sequences (n ~ 100) and structures of psychrophilic isocitrate dehydrogenase and mesophilic isocitrate dehydrogenase extracted from databases. Sequences had been analyzed in BLOCK and non-BLOCK format. The sequences of psychrophiles and mesophiles create two separate clades. The number of charged and uncharged polar residues is very much high in psychrophilic proteins. The formation of long network aromatic–aromatic interactions and network aromatic–sulfur interactions are very crucial for psychrophilic protein stability. Identification of these types of interactions is also a novelty of this study. Favorable mutation of charged residues with high-energy contributions affects the protein stability. This study will help in protein engineering.