Antibacterial peptide mostly active against Gram-positive bacteria (PubMed:20605792). 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). Expressed in hemocytes. After a bacterial challenge, the level of transcripts decreases dramatically in the circulating hemocytes. This decrease can be correlated with an increase of transcripts in the gill and the mantle tissue, suggesting a possible migration of the hemocytes expressing Cg-defh2 towards the tissues implicated in the first defense barrier of the oyster. Has the structural arrangement of an alpha-helix connected to a beta-sheet by disulfide bonds (CSalpha/beta). Belongs to the invertebrate defensin family.