Study of arachidonoyl specificity in two enzymes of the PI cycle.
Study of arachidonoyl specificity in two enzymes of the PI cycle.
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DOI：
10.1016/j.jmb.2011.03.071
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发表时间：
2011-06-03
影响因子：
5.6
通讯作者：
Epand RM
中科院分区：
文献类型：
--
作者：
Shulga YV;Topham MK;Epand RM
我们在两种作用于多不饱和脂肪酸的酶中发现了L-X(3-4)- r - x (2)-L-X(4)- g残基的保守模式，其中- x (n)-代表任意氨基酸的n个残基，即二酰基甘油激酶epsilon （DGKε）和磷脂酰肌醇-4-磷酸-5激酶Iα (PIP5K Iα)。DGKε是DGK的10种哺乳动物亚型中唯一具有花生四烯醇基特异性的亚型，也是唯一具有上述基元的亚型。该基序中必需残基的突变导致花生四烯酰基特异性的丧失。此外，DGKα仅通过替换一个残基就可以转化为具有该基序的酶。当DGKα突变使其获得基序时，该酶也对含有花生四烯酰基的二酰基甘油具有一定的特异性。该基元也存在于磷脂酰肌醇-4-磷酸-5-激酶的异构体中，我们证明其底物具有花生四烯酰基特异性。在该同工异构体的识别基序内的单个残基突变导致对花生四烯酰基底物的活性丧失。酰基链特异性对磷脂酰肌醇-4-磷酸-5激酶的磷脂酸活化的重要性也得到了证明。我们还证明了磷脂酸活化的酰基链依赖依赖于底物。这是第一次在DGKε和PIP5K Iα两种酶中发现一个基序赋予酰基链特异性。
We identified a conserved pattern of residues L-X(3–4)-R-X(2)-L-X(4)-G, in which -X(n)- represents n residues of any amino acids, in two enzymes acting on polyunsaturated fatty acids, diacylglycerol kinase epsilon (DGKε) and phosphatidylinositol-4-phosphate-5-kinase Iα (PIP5K Iα). DGKε is the only one of the 10 mammalian isoforms of DGK that exhibits arachidonoyl specificity and is the only isoform with the aforementioned motif. Mutations of the essential residues in this motif result in loss of arachidonoyl specificity. Furthermore, DGKα can be converted to an enzyme having this motif by substituting only one residue. When DGKα was mutated so that it gained the motif, the enzyme also gained some specificity for arachidonoyl-containing diacylglycerol. This motif is also present in an isoform of phosphatidylinositol-4-phosphate-5-kinase that we demonstrated had arachidonoyl-specificity for its substrate. Single residue mutations within the identified motif of this isoform result in loss of activity against an arachidonoyl substrate. The importance of acyl chain specificity for the phosphatidic acid activation of phosphatidylinositol-4-phosphate-5-kinase is also shown. We also demonstrate that the acyl chain dependence of this phosphatidic acid activation is dependent on the substrate. This is the first demonstration of a motif that endows specificity for an acyl chain in two studied enzymes, DGKε and PIP5K Iα.
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影响因子：
2.9
作者：
Milne, Stephen B.;Ivanova, Pavlina T.;Armstrong, Michelle D.;Myers, David S.;Lubarda, Jovana;Shulga, Yulia V.;Topham, Matthew K.;Brown, H. Alex;Epand, Richard M.
通讯作者：
Epand, Richard M.
影响因子：
6.5
作者：
Radmark, Olof;Samuelsson, Bengt
通讯作者：
Samuelsson, Bengt
影响因子：
4.8
作者：
Kohama, T;Olivera, A;Spiegel, S
通讯作者：
Spiegel, S
影响因子：
4.8
作者：
Li, H;Papadopoulos, V
通讯作者：
Papadopoulos, V
影响因子：
4.4
作者：
PAPPU, AS;HAUSER, G
通讯作者：
HAUSER, G