Molecular simulations of myoglobin adsorbed on rutile (1 1 0) and (0 0 1) surfaces

The adsorption of myoglobin (Mb) on the surface of titanium dioxide is very important for the preparation of biosensors. Adsorption orientation and conformation of Mb on rutile (1 1 0) and (0 0 1) surfaces were investigated by combining Monte Carlo and molecular dynamics methods. The orientation, DSSP, superimposed structure, root-mean-square deviation and gyration radius of Mb were analyzed. Furthermore, the distribution of water molecules on rutile (1 1 0) and (0 0 1) surfaces and representative snapshots of water molecules at different rutile interfaces were also discussed in detail. Simulation results show that adsorbed Mb conformations are not influenced by surfaces obviously because of the strong hydrophilicity of both surfaces. Two layers of water molecules form on both rutile (1 1 0) and (0 0 1) surfaces. After 80 ns molecular dynamics simulation, the heme of Mb is close to the rutile (0 0 1) surface and far away from the rutile (1 1 0) surface; this infers that electron transfer pathway of Mb is closer to the rutile (0 0 1) surface, which is favorable for faster electron transfer.