Ganz T, Selsted M E, Lehrer R I
Will Rogers Pulmonary Research Laboratory, School of Medicine, University of California, Los Angeles 90024-1736.
Eur J Haematol. 1990 Jan;44(1):1-8. doi: 10.1111/j.1600-0609.1990.tb00339.x.
Defensins are a family of small, variably cationic proteins which are highly abundant in the granules of mammalian phagocytes. Three defensins, HNP-1, 2, and 3, comprise 30-50% of total protein in azurophil granules of human neutrophils. Some defensins are broadly antimicrobial, antiviral and cytotoxic, while others are chemotactic, opsonic, or may modulate hormonal responses. The defensin molecule typically consists of 29-34 amino acids with a conserved pattern of disulfide linkage among its 6 cysteines. The three-dimensional fold of defensins forms a highly amphiphilic molecule. Microbicidal and cytotoxic properties of defensins are most likely a consequence of their ability to insert into biological membranes and to generate pores. Defensins are synthesized by phagocytes or their precursors as a 94-95 amino acid charge-neutralized preprodefensin, an arrangement which may avoid cytotoxic injury to the phagocyte. Although defensins were recognized only recently, the existence of homologs in certain invertebrates suggests that they are ancestral components of the host defense system.
防御素是一类小的、带不同阳离子的蛋白质家族，在哺乳动物吞噬细胞的颗粒中高度丰富。三种防御素，即人中性粒细胞嗜天青颗粒中总蛋白的30 - 50%，分别是HNP - 1、2和3。一些防御素具有广泛的抗菌、抗病毒和细胞毒性作用，而其他防御素具有趋化、调理作用，或可能调节激素反应。防御素分子通常由29 - 34个氨基酸组成，其6个半胱氨酸之间具有保守的二硫键连接模式。防御素的三维折叠形成一个高度两亲性的分子。防御素的杀菌和细胞毒性特性很可能是它们插入生物膜并形成孔道能力的结果。防御素由吞噬细胞或其前体作为一种94 - 95个氨基酸的电荷中和前原防御素合成，这种排列方式可能避免对吞噬细胞的细胞毒性损伤。尽管防御素直到最近才被认识到，但某些无脊椎动物中同源物的存在表明它们是宿主防御系统的祖先成分。
