At present antimicrobial peptides are a competitive alternative to classic antibiotics. Their wide use is limited to a number of problems associated with the generation of toxic peptides in E. coli cells and their delivery to the target site in the organism. We have verified the idea that could help solving this problem. We proposed that green fluorescent protein can be used as a container for “storage” of an antibacterial peptide. An alpha-helix on which a chromophore is formed is initially “hidden” inside the barrel of green fluorescent protein. The alpha-helix itself contains hydrophobic amino acids, and nearby in the center of the barrel there are many bound water molecules. Therefore we suggested that the central alpha-helix of green fluorescent protein can be substituted for an antibacterial peptide. It is rather difficult to realize this idea, and at the first stage there appear several issues without solving which it is impossible to continue the studies as required. Will green fluorescent protein with the substituted alpha-helix fold? Can the chromophore be formed in this case? Is this construction toxic to the cell? We modified green fluorescent protein. The central alpha-helix was substituted by the sequence of antimicrobial peptide bactenecin. The results of our experiments show that such a chimera (mutant) protein is compact, soluble, nontoxic to the cell. However it is strongly destabilized, which may be a reason why the chromophore is not formed. Our results demonstrate that the idea to use green fluorescent protein as a “container” for small peptides is quite realizable.
green fluorescent protein, antibacterial peptides, bactenecin, molecular dynamics
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