人体汗液具有杀菌功效早就为人所知，但其杀菌原理却长期未知。对此，德国研究人员给出了答案。相关论文发表在3月9日的美国《生物化学期刊》（JBC）上。
德国蒂宾根大学教授比吉特·席特克和卡尔斯鲁厄理工大学阿纳·乌尔里希领导的研究小组发现，人体皮肤不仅是阻挡异物的天然屏障，还拥有一套抵抗细菌、病毒和真菌的化学防御系统。在这套系统中，人体汗腺可生产一种DCD多肽，这种通过汗液分布在皮肤表面的多肽不仅可维持皮肤上正常菌群的稳定，还可在致病细菌的细胞膜上形成离子通道，破坏其膜电位，像抗生素一样防止皮肤感染。
一般来讲，汗腺会“固定”生产这种杀菌多肽，以满足皮肤保护基本需求，但当皮肤受到细菌感染时，DCD的产量会随之增加。（生物谷Bioon.com）
doi:10.1074/jbc.M111.332270
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Structure-Activity Analysis of the Dermcidin-derived Peptide DCD-1L, an Anionic Antimicrobial Peptide Present in Human Sweat
Maren Paulmann, Thomas Arnold, Dirk Linke, Suat zdirekcan, Annika Kopp, Thomas Gutsmann, Hubert Kalbacher, Ines Wanke, Verena J. Schuenemann, Michael Habeck, Jochen Bürck, Anne S. Ulrich and Birgit Schittek
Dermcidin encodes the anionic amphiphilic peptide DCD-1L, which displays a broad spectrum of antimicrobial activity under conditions resembling those in human sweat. Here, we have investigated its mode of antimicrobial activity. We found that DCD-1L interacts preferentially with negatively charged bacterial phospholipids with a helix axis that is aligned flat on a lipid bilayer surface. Upon interaction with lipid bilayers DCD-1L forms oligomeric complexes that are stabilized by Zn2+. DCD-1L is able to form ion channels in the bacterial membrane, and we propose that Zn2+-induced self-assembly of DCD-1L upon interaction with bacterial lipid bilayers is a prerequisite for ion channel formation. These data allow us for the first time to propose a molecular model for the antimicrobial mechanism of a naturally processed human anionic peptide that is active under the harsh conditions present in human sweat.
