Mahnaz Shojapour; , Faezeh Fatemi; Reza Haji Hosseini; Marzieh Dehghan Shasaltaneh
Abstract
Abstract Acidithiobacillus ferrooxidans (Af) is an acidophilic bacterium involved in the bioleaching process. Cytochrome c552 (Cyc1) is a periplasmic protein that has a key role in the electron transportation in the respiratory chain. The presence of both heme A and B in the Cyc1 structure and its role ...
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Abstract Acidithiobacillus ferrooxidans (Af) is an acidophilic bacterium involved in the bioleaching process. Cytochrome c552 (Cyc1) is a periplasmic protein that has a key role in the electron transportation in the respiratory chain. The presence of both heme A and B in the Cyc1 structure and its role in taking electrons from the previous protein and electron transfer to the next protein is the main reason for choosing this protein. In this research, with purpose of improving the bioleaching process, glutamate 122 and histidine 54 Cyc1 were selected for point mutation in bioinformatics studies. Mutations were performed by PYMOL software and simulated molecular dynamics for wild proteins, and mutant E122D, H54I in Cyc1. The conformational changes of mutated protein were investigated by SASA, Rg, NH bond analysis. Our results confirmed that the mutated proteins retained its stability during the simulation. By converting glutamate to aspartate, an acid molecule changed into a more acidic molecule leading to the further decreased redox potential at the rusticyanin midpoint resulted into the improved electron transfer from the Rcy to Cyc1 . This will also cause the increased electron transfer rate to heme A. In the case of converting histidine 54 to isoleucine, an electrostatic imidazole loop changed into an amino acid with the root of R with lack of charge which leads to the formation of a stronger hydrogen bond between the two amino acids. Therefore, probably the electron transfers between Cyc1 and CcO is improved through a water molecule (W79) leading to increased bioleaching rate.
