Evaluation of point mutation on the stability of Cyc1 in A. ferrooxidans by MD simulation

Mahnaz Shojapour¹ Faezeh Fatemi² Somayeh Farahmand³

1) Department of Science, Payame Noor University, Tehran shargh, Tehran, Iran Email:
2) Materials and Nuclear Fuel Research School, Nuclear Science and Technology Research Institute, Tehran, IranEmail:
3) Department of Science, Payame Noor University, Tehran shargh, Tehran, Iran

Publication : 2nd. International Congress on science & Engineering - paris(parisconf.com)
Abstract :
Cyc1 is a periplasmic protein in the respiratory chain of the Acidithiobacillus ferrooxidans (Af) bacterium that has a key role in the electron transportation. These bacteria obtain its own energy from the oxidation of Fe2+ to Fe+3. The electrons are directed through Cyc2, RCY (rusticyanin), Cyc1 and Cox aa3 proteins to O2. The presence of both heme A and B in the Cyc1 structure and its role in taking electrons from the previous protein (RCY) is the main reason for choosing this protein. We selected Glu121 of Cyc1 as the point mutation in bioinformatics studies because of electron receiving from His 143 of Rcy. Molecular dynamics simulations were performed for wild and mutant types of Cyc1 protein. The conformational changes of mutated protein were investigated by SASA, Rg, NH bond, and DSSP analysis. Our results confirmed that the mutant protein retained its stability during the simulation. With converting glutamate 121 into aspartate, an acidic residue (Glu121) becomes a more acidic residue (Asp121), and His143 more deprotonated inducing a reduction of the redox potential at the rusticyanin midpoint improving the electron transfer to Cyc1 protein.
Keywords : Acidithiobacillus ferrooxidans; Cyc1; Electron transportation chain; Molecular dynamics simulation; Point Mutation.