Antibacterial peptide mostly active against Gram-positive bacteria (M.lysodeikticus, S.aureus, and the marine bacteria, B.stationis, and M.maritypicum) (PubMed:16246846). It acts by selectively inhibiting peptidoglycan biosynthesis through complex formation with the cell wall precursor lipid II (1:1 molar ratio) thus inhibiting cell wall synthesis (PubMed:20605792). It does not disrupt cell membranes (PubMed:20605792). Is noticeably more potent than Cg-Defh1 (PubMed:20605792). It shows no or limited activities against Gram-negative bacteria and filamentous fungi (PubMed:16246846). Expressed in the mantle. Low or no expression in most of the organs analyzed, including hemocytes, heart, digestive gland, and gills. Constitutively expressed. Has the structural arrangement of an alpha-helix connected to a beta-sheet by disulfide bonds (CSalpha/beta). The Cys-26-Pro-27 bond is in cis conformation. Belongs to the invertebrate defensin family.