Specificity of lipoprotein-associated phospholipase A(2) toward oxidized phosphatidylserines: liquid chromatography-electrospray ionization mass spectrometry characterization of products and computer modeling of interactions.
Specificity of lipoprotein-associated phospholipase A(2) toward oxidized phosphatidylserines: liquid chromatography-electrospray ionization mass spectrometry characterization of products and computer modeling of interactions.
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DOI：
10.1021/bi301024e
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发表时间：
2012-12-04
期刊：
影响因子：
2.9
通讯作者：
Kagan VE
中科院分区：
文献类型：
--
作者：
Tyurin VA;Yanamala N;Tyurina YY;Klein-Seetharaman J;Macphee CH;Kagan VE
Ca2+ 独立脂蛋白相关磷脂酶 A2 (Lp-PLA2) 是磷脂酶 A2 超家族的一员，其显着特征是对磷脂中氧化修饰的 sn-2 脂肪酸残基具有高度特异性，尤其是对磷脂酰胆碱 (PC) 的过氧化物质进行了很好的表征。 Lp-PLA2 水解磷脂酰丝氨酸 (PS) 的过氧化物质（作为专业吞噬细胞清除凋亡细胞的识别信号）的能力以及反应产物尚未得到研究。我们对 PS 的氧化/水解分子种类进行了基于 LC-MS-ESI 的结构表征 - 在 sn-2 位 (C18:0/C18:2) 或在 sn-1 和 sn-2 位 (C18:2/C18:2) 均含有亚油酸 - 在细胞色素 c/ H2O2 驱动的酶氧化反应中形成。细胞色素 c 已被选为过氧化反应的催化剂，因为它可能参与凋亡细胞中的 PS 氧化。我们发现 Lp-PLA2 催化氧化 PS 物种的非截短和截短（氧化断裂）物种的水解，尽管效率不同，并对主要反应产物（亚油酸的氧化衍生物以及溶血 PS 的非氧化和氧化物种）进行了详细表征。在亚油酸产品中，C9 位氧化的衍生物最丰富，其中包括 9-羟基十八碳二烯酸 (9-HODE)（G 蛋白偶联受体 G2A 的有效配体）。 Lp-PLA2 与不同 PS 氧化物质相互作用的计算机模型表明，它们能够与催化三联体的 Ser273 和 His351 接近（<5Å）结合。对于氧化 PS 的 9-羟基-和 9-氢过氧-衍生物，sn-2 酯键与 Ser273 残基（直接攻击 sn-2 键的亲核试剂）非常接近（<3Å），从而有利于水解反应。我们认为，Lp-PLA2 产生的氧化修饰游离脂肪酸和溶血 PS 物质可能代表促进和调节控制炎症所必需的细胞凋亡和吞噬程序执行的重要信号。
Ca2+ independent lipoprotein associated phospholipase A2 (Lp-PLA2) is a member of the phospholipase A2 superfamily with a distinguishing characteristic of high specificity for oxidatively modified sn-2 fatty acid residues in phospholipids which has been especially well characterized for peroxidized species of phosphatidylcholines (PC). The ability of Lp-PLA2 to hydrolyze peroxidized species of phosphatidylserine (PS) – acting as a recognition signal for clearance of apoptotic cells by professional phagocytes - as well as the products of the reaction have not been investigated. We performed LC-MS-ESI-based structural characterization of oxygenated/hydrolyzed molecular species of PS - containing linoleic acid in either sn-2 position (C18:0/C18:2) or in both sn-1 and sn-2 positions (C18:2/C18:2) - formed in cytochrome c/ H2O2 driven enzymatic oxidation reaction. Cytochrome c has been chosen as a catalyst of peroxidation reactions due to its likely involvement in PS oxidation in apoptotic cells. We found that Lp-PLA2 catalyzed the hydrolysis of both non-truncated and truncated (oxidatively fragmented) species of oxidized PS species albeit with different efficiencies and performed detailed characterization of the major reaction products – oxygenated derivatives of linoleic acid as well as non-oxygenated and oxygenated species of lyso-PS. Among linoleic acid products, derivatives oxygenated at the C9 position, including 9-hydroxyoctadecadienoic acid (9-HODE) – a potent ligand of G protein-coupled receptor G2A - were the most abundant. Computer modeling of interactions of Lp-PLA2 with different PS oxidized species indicated that they are able to bind in proximity (<5Å) to Ser273 and His351 of the catalytic triad. For 9-hydroxy- and 9-hydroperoxy- derivatives of oxidized PS, the sn-2 ester bond was positioned within the very close proximity (<3Å) from the Ser273 residue - a nucleophile directly attacking the sn-2 bond – thus favoring the hydrolysis reaction. We suggest that oxidatively modified free fatty acids and lyso-PS species generated by Lp-PLA2 may represent important signals facilitating and regulating execution of apoptotic and phagocytosis programs essential for control of inflammation.
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影响因子：
13.6
作者：
Frasch SC;Bratton DL
通讯作者：
Bratton DL
影响因子：
5.8
作者：
Chauffe, Ryan J.;Wilensky, Robert L.;Mohler, Emile R., III
通讯作者：
Mohler, Emile R., III
影响因子：
4.8
作者：
Hosono, H;Aoki, J;Inoue, K
通讯作者：
Inoue, K
影响因子：
8.7
作者：
Freeman GJ;Casasnovas JM;Umetsu DT;DeKruyff RH
通讯作者：
DeKruyff RH
DOI：
10.1097/mco.0b013e32802b7030
发表时间：
2007-03-01
影响因子：
3.1
作者：
Bazan, Nicolas G.
通讯作者：
Bazan, Nicolas G.