Effect of Valine 172 residue alteration using a site-directed mutagenesis on the structure and function of mnemiopsin2: a bioinformatics study

Calcium-regulated photoproteins have been used as appropriate tools for intracellular and extracellular studies due to their unique properties, such as high sensitivity, low-level background signal, etc. Mnemiopsin2 is a member of calcium-regulated photoproteins, which like other photoproteins, emits light in the presence of substrates such as coelenterazine, molecular oxygen, and calcium initiator ions. The residue of valine 172 is the second residue in the EF-hand IV loop of mnemiopsin2. Since the EF-hand IV loop is one of three active loops for calcium binding, valine 172 was replaced with alanine residue (as a neutral residue, in order to reduce the spatial interference of this position), isoleucine and leucine (as the residues similar to valine in terms of the side chain amino acid), and the effect of these changes was evaluated on mnemiopsin2 performance. For this, the mutation models were designed using the Modeller 9v19 software, and the best model was selected using ModEval, SAVES, SPdbViewer software and PIC Server. After that, the three-dimensional structure of the mutants was designed using Chimera software. The investigation of the interactions via the PIC server has been shown to increase only in the mutation of the V172A hydrophobic interactions. In all three mutations, the main chain reactions, ionic and aromatic decreased, as well as the main chain-side chain and cationic interactions in all three mutated increase. The results of the Instability Index index obtained from the Prot Param server indicate a decrease in the stability of the mutations, which seems to be due to the replacement of the side chain of the residues

کلیدواژه ها:

Mnemiopsin2 ، Site-directed mutagenesis ، Structural stability ، Valine 172