School of Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, Scotland, UK.
Dev Comp Immunol. 2011 Feb;35(2):155-63. doi: 10.1016/j.dci.2010.08.015. Epub 2010 Sep 24.
Phenoloxidase enzymes and the associated pro-phenoloxidase activation cascade play an essential role in the immune response of arthropods. Phenoloxidase activity can be elicited in the oxygen carrier, hemocyanin, by the addition of the artificial inducer, SDS. There is some evidence to support hemocyanin acting as a phenoloxidase in vivo; however, the identity of natural activators remains unclear. This study explores the role of the phospholipid, phosphatidylserine, as a possible natural activator of hemocyanin-derived phenoloxidase activity. Characterisation of the structural changes associated with activation of hemocyanin-derived phenoloxidase suggests that phosphatidylserine induces similar conformational changes to those caused by the artificial inducer, SDS. We propose that anionic phospholipids, in particular phosphatidylserine, may act as natural activators of hemocyanin-derived phenoloxidase.
酚氧化酶酶及其相关的原酚氧化酶激活级联在节肢动物的免疫反应中起着至关重要的作用。酚氧化酶活性可以通过添加人工诱导剂 SDS 来诱导氧载体血蓝蛋白。有一些证据支持血蓝蛋白在体内作为酚氧化酶发挥作用；然而，天然激活剂的身份仍不清楚。本研究探讨了磷脂酰丝氨酸作为血蓝蛋白衍生的酚氧化酶活性的可能天然激活剂的作用。对与血蓝蛋白衍生的酚氧化酶激活相关的结构变化的特征描述表明，磷脂酰丝氨酸诱导与人工诱导剂 SDS 引起的相似的构象变化。我们提出阴离子磷脂，特别是磷脂酰丝氨酸，可能作为血蓝蛋白衍生的酚氧化酶的天然激活剂。
