IDENTIFICATION OF THE REGION THAT PLAYS AN IMPORTANT ROLE IN DETERMINING ANTIBACTERIAL ACTIVITY OF BOVINE SEMINALPLASMIN

Seminalplasmin (SPLN) is a 47-residue protein isolated from bovine sem inal plasma having potent antimicrobial activity against a broad spect rum of microorganisms. SPLN, also known as caltrin, acts as a calcium transport regulator in bovine sperms. Analysis of the sequence of SPLN reveals a 27-residue stretch with the sequence SLSRYAKLANRLANPKL-LETF LSKWIG more hydrophobic than the rest of the protein. It is demonstrat ed that a synthetic peptide corresponding to this 27-residue segment h as antimicrobial activity comparable to that of SPLN. It does not exhi bit hemolytic activity at concentrations where antibacterial activity is observed. Since P27 can be conveniently obtained in large amounts b y chemical synthesis, it could serve not only as a starting compound t o obtain peptides with improved antibacterial activity but also to und erstand the role of SPLN in reproductive physiology.