PROBLEM TO BE SOLVED: To provide an antimicrobial peptide which can impart an antimicrobial activity to a fusion protein, and to provide the fusion protein which imparts or can impart an antimicrobial activity derived from an antimicrobial peptide to any protein (e.g. silk) in addition to a function of the protein, and to provide a method for producing silk to which functionality is imparted.SOLUTION: The invention provides a novel peptide (a peptide with a repetition structure of a modified peptide derived from beetle defensin which has an antibacterial property) which can impart an antimicrobial activity to fusion proteins. The invention also provides the fusion protein which has an antimicrobial activity with the repetition peptide. The invention also provides a silk to which functionality is imparted.
