The invention provides a
melittin polymer, which is formed by at least connecting disulfide bonds between two
melittin variant molecules after a
melittin variant is formed by mutating
alanine at the fourth site of an
amino acid sequence of a melittin
monomer into
cysteine and mutating
isoleucine at the twentieth site into
cysteine in the
amino acid sequence of the melittin
monomer. The preparation method of the melittin
polymer comprises the following steps: obtaining a melittin variant through
escherichia coli
recombinant expression, and purifying and oxidizing the obtained melittin variant through a
nickel column to obtain the melittin
polymer, and carrying out gel
filtration chromatography on the obtained melittin polymer to obtain the purified melittin polymer. The invention also provides an application of the melittin polymer, and the melittin polymer is used for preparing antibacterial drugs or antibacterial feed additives. The prepared melittin polymer can effectively reduce the
toxicity to red blood cells, has relatively strong environmental responsiveness and stability, and can effectively prolong the antibacterial aging.