[Comparative studies of structural properties of melittin in water and trifluroethanol/water mixture by the molecular dynamics method].

The structural properties and dynamic behavior of the antimicrobial peptide melittin in hydrophobic and polar environments have been investigated. The main characteristics of the secondary structure of melittin in different media have been analyzed, and compared with the data on the ideal alpha-helix. It has been shown that melittin is an alpha-helix bent in the region of residue Pro14; in this case, the N-terminus of the peptide tends to unfold, while the C-terminal segment (residues 14-23) retains the helical structure for 20 ns of the simulation. 2,2,2-Trifluoroethanol molecules stabilize the helical structure of the peptide through lowering the dielectric constant of the environment and preferential accumulation nearby particular segments of the polypeptide chain.