Beta-defensins are small cationic peptides that have triple-stranded beta-sheet structure [1]. They are characterized by the presence of multiple cysteine residues (forming three distinctive intramolecular disulfide bridges) and a highly similar tertiary structure known as the defensin motif [1]. All beta-defensin genes encode a precursor peptide that consists of a hydrophobic, leucine-rich signal sequence, a pro-sequence, and a mature six-cysteine defensin motif at the carboxy terminus [2]. They exhibit broad-spectrum antimicrobial properties and contribute to mucosal immune responses at epithelial sites [3]. Several beta-defensins family members have been shown to play essential roles in sperm maturation and fertility in rats, mice and humans [3]. In addition to the wide spectrum of antimicrobial activity, mammalian beta-defensins have been reported to have other roles in the immune system, such as the chemotactic ability for immature dendritic cells and memory T-cells via chemokine receptor-6 demonstrated by human beta-defensin-2 [4]. This entry contains beta-defensins such as DEFB136 Swiss:Q30KP8, the mouse homologue Defb42 Swiss:Q8BVB5 and Ostricacin-3 Swiss:P85115.

1: Identification of three novel ostricacins: an update on the phylogenetic perspective of beta-defensins. Sugiarto H, Yu PL; Int J Antimicrob Agents. 2006;27:229-235. PMID:16459058

2: Cross-species analysis of the mammalian beta-defensin gene family: presence of syntenic gene clusters and preferential expression in the male reproductive tract. Patil AA, Cai Y, Sang Y, Blecha F, Zhang G; Physiol Genomics. 2005;23:5-17. PMID:16033865

3: Androgenic regulation of beta-defensins in the mouse epididymis. Hu SG, Zou M, Yao GX, Ma WB, Zhu QL, Li XQ, Chen ZJ, Sun Y; Reprod Biol Endocrinol. 2014;12:76. PMID:25099571

4: The roles of antimicrobial peptides in innate host defense. Diamond G, Beckloff N, Weinberg A, Kisich KO; Curr Pharm Des. 2009;15:2377-2392. PMID:19601838