Defensins of all three subfamilies are expressed as preprodefensins containing an N-terminal signal peptide followed by the propeptide that contains the prosegment and the folded/oxidized mature peptide sequence [26] . The prosegment in aand hdefensin precursors is ,45 amino acids in length, but that of bdefensin precursors is typically very short. In a-defensins, studies suggest that the anionic prosegment interacts with residues present in the mature peptide to maintain it in an inactive state until it reaches the correct cellular location, possibly to protect cellular compartments from peptide-mediated cytotoxic effects [27, 28, 29] .