Expression of an antimicrobial peptide identified in the male reproductive system of rats.

Bin1b is a beta-defensins-like molecule originally isolated from the rat epididymis. Owing to its bactericidal activity, Bin1b may have therapeutic properties suitable for the treatment of sexually transmitted diseases. The amino terminus of the mature Bin1b peptide contains a conserved myristoylated Gly residue. We studied the requirement of the terminal myristoylated Gly residue in the bactericidal activity of Bin1b and found that the terminal myristoylated Gly residue is not essential for the bactericidal activity. In addition, we expressed the tandem repeats of Bin1b in Escherichia coli and found that two tandem repeats of Bin1b protein were successfully expressed. The bacterially expressed tandem Bin1b repeats may be used in a diverse array of biochemical and cell biological studies.