Department of Marine Biology and Laboratory for Evolution and Development, Ocean University of China, Qingdao 266003, China.
Mol Biol Rep. 2011 Mar;38(3):1847-51. doi: 10.1007/s11033-010-0301-1. Epub 2010 Sep 17.
Apolipoprotein D (ApoD), a member of lipocalin, has been recently shown to be involved in regulating protection from oxidative stress. The absence of ApoD in mouse and Drosophila can reduce the resistance to oxidative stress and shorten lifespan. However, little information is available regarding the expression in vitro of ApoD and its biochemical properties. Amphioxus (Branchiostoma belcheri) ApoD, BbApoD, is an archetype of vertebrate ApoD proteins. In this study, the prokaryotic expression plasmid pET32a-BbApoD was constructed and recombinant BbApoD expressed in Escherichia coli BL21 and purified. Antioxidation assays showed that the recombinant BbApoD protein had the capacities to scavenge hydroxyl radicals (≥ 240 μg/ml) and to prevent nicking of the supercoiled DNA (≥ 100 μg/ml) in vitro, providing a biochemical evidence for antioxidant role of ApoD. This supports the notion that ApoD is part of the mechanisms regulating protection from oxidative stresses.
载脂蛋白 D（ApoD）是脂联素家族的一员，最近的研究表明其参与调节氧化应激的保护作用。在小鼠和果蝇中缺失 ApoD 会降低其对氧化应激的抵抗力并缩短寿命。然而，关于 ApoD 的体外表达及其生化特性的信息却很少。文昌鱼（Branchiostoma belcheri）ApoD，BbApoD，是脊椎动物 ApoD 蛋白的原型。本研究构建了原核表达质粒 pET32a-BbApoD，并在大肠杆菌 BL21 中表达和纯化了重组 BbApoD。抗氧化测定表明，重组 BbApoD 蛋白具有清除羟自由基（≥240μg/ml）和防止超螺旋 DNA 断裂（≥100μg/ml）的能力，为 ApoD 的抗氧化作用提供了生化证据。这支持了 ApoD 是调节氧化应激保护机制的一部分的观点。
