Omega-3 fatty acids are oxygenated at the n-7 carbon by the lipoxygenase domain of a fusion protein in the cyanobacterium Acaryochloris marina.
Omega-3 fatty acids are oxygenated at the n-7 carbon by the lipoxygenase domain of a fusion protein in the cyanobacterium Acaryochloris marina.
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DOI：
10.1016/j.bbalip.2009.09.004
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发表时间：
2010-01
期刊：
影响因子：
--
通讯作者：
Brash AR
中科院分区：
文献类型：
--
作者：
Gao B;Boeglin WE;Brash AR
脂氧合酶（LOX）存在于大多数含有多不饱和脂肪酸的生物体中，通常作为单个基因存在，尽管偶尔编码为与过氧化氢酶相关血红素蛋白的融合蛋白。这样的融合蛋白发生在蓝藻Acaryochloris marina，在这里，我们报告了新的催化活性的LOX结构域。在大肠杆菌中表达了全长蛋白和C端LOX结构域，并通过UV、HPLC、GC-MS、CD等方法对表达产物进行了表征。所有ω-3多不饱和脂肪酸都被n-7位的LOX结构域氧化，并具有R立体特异性：α-亚麻酸和A中最丰富的脂肪酸。marina，十八碳四烯酸（C18.4ω3）转化为相应的12 R-氢过氧化物，二十碳五烯酸转化为14 R-氢过氧化物，二十二碳六烯酸转化为16 R-氢过氧化物。ω-6多不饱和化合物在n-10位被氧化，从亚油酸形成9 R-氢过氧-十八碳二烯酸，从花生四烯酸形成11 R-氢过氧-二十碳四烯酸。十八碳四烯酸通过全长融合蛋白的代谢转化需要其12 R氧化，随后通过过氧化氢酶相关结构域转化为新的丙二烯环氧化物，其可能是环戊烯酮脂肪酸或其他信号分子的前体（Gao等人，J.Biol.Chem.284：22087-98，2009）。尽管ω-3脂肪酸和脂氧合酶广泛存在，但这似乎是第一次描述专门利用ω-3脂肪酸的末端戊二烯的LOX催化氧化。
Lipoxygenases (LOX) are found in most organisms that contain polyunsaturated fatty acids, usually existing as individual genes although occasionally encoded as a fusion protein with a catalase-related hemoprotein. Such a fusion protein occurs in the cyanobacterium Acaryochloris marina and herein we report the novel catalytic activity of its LOX domain. The full-length protein and the C-terminal LOX domain were expressed in Escherichia coli, and the catalytic activities characterized by UV, HPLC, GC-MS, and CD. All omega-3 polyunsaturates were oxygenated by the LOX domain at the n-7 position and with R stereospecificity: α-linolenic and the most abundant fatty acid in A. marina, stearidonic acid (C18.4ω3), are converted to the corresponding 12R-hydroperoxides, eicosapentaenoic acid to its 14R-hydroperoxide, and docosahexaenoic acid to its 16R-hydroperoxide. Omega-6 polyunsaturates were oxygenated at the n-10 position, forming 9R-hydroperoxy-octadecadienoic acid from linoleic acid and 11R-hydroperoxy-eicosatetraenoic acid from arachidonic acid. The metabolic transformation of stearidonic acid by the full-length fusion protein entails its 12R oxygenation with subsequent conversion by the catalase-related domain to a novel allene epoxide, a likely precursor of cyclopentenone fatty acids or other signaling molecules (Gao et al, J. Biol. Chem. 284:22087-98, 2009). Although omega-3 fatty acids and lipoxygenases are of widespread occurrence, this appears to be the first description of a LOX-catalyzed oxygenation that specifically utilizes the terminal pentadiene of omega-3 fatty acids.
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影响因子：
4.8
作者：
Schneider, C;Tallman, KA;Brash, AR
通讯作者：
Brash, AR
DOI：
10.1016/j.bbagen.2007.10.010
发表时间：
2008-02-01
影响因子：
3
作者：
Lohelaid, Helike;Jarving, Reet;Samel, Nigulas
通讯作者：
Samel, Nigulas
影响因子：
3.7
作者：
Mimuro, Mamoru;Tomo, Tatsuya;Tsuchiya, Tohru
通讯作者：
Tsuchiya, Tohru
影响因子：
3.9
作者：
Mortimer, M;Järving, R;Järving, I
通讯作者：
Järving, I
影响因子：
4.1
作者：
PEERS, KE;COXON, DT;CHAN, HWS
通讯作者：
CHAN, HWS