Enterobactin biosynthesis in Escherichia coli: Isochorismate lyase (EntB) is a bifunctional enzyme that is phosphopantetheinylated by EntD and then acylated by EntE using ATP and 2,3-dihydroxybenzoate
Enterobactin biosynthesis in Escherichia coli: Isochorismate lyase (EntB) is a bifunctional enzyme that is phosphopantetheinylated by EntD and then acylated by EntE using ATP and 2,3-dihydroxybenzoate
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DOI：
10.1021/bi970453p
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发表时间：
1997-07-15
期刊：
影响因子：
2.9
通讯作者：
Walsh, CT
中科院分区：
文献类型：
--
作者：
Gehring, AM;Bradley, KA;Walsh, CT
在蚯蚓大肠杆菌中，铁载体分子肠杆菌素是通过在2，3-二羟基苯甲酸酯（2，3-DHB）和L-丝氨酸之间形成酰胺键以及在三个这样的N-酰化丝氨酸残基之间形成酯键来响应铁剥夺而合成的。我们表明，EntB，以前被描述为生产2，3-DHB所需的异分支酸裂解酶，是一种双功能蛋白质，也用作在肠杆菌素装配中起作用的芳基载体蛋白（ArCP），EntB在EntD催化的反应中在C末端附近被磷酸泛酰巯基乙胺化，k（cat）为5 min（-1），apo-EntB的K-m为6.5 μ M。然后在由EntE催化的反应中用2，3-DHB酰化该全-EntB，先前描述为2，3-DHB-AMP连接酶，其中k（cat）为100 min（-1），k（m）为100 min（-1）。
In Escherichin coli, the siderophore molecule enterobactin is synthesized in response to iron deprivation by formation of an amide bond between 2,3-dihydroxybenzoate (2,3-DHB) and L-serine and formation of eater linkages between three such N-acylated serine residues, We show that EntB, previously described as the isochorismate lyase required for production of 2,3-DHB, is a bifunctional protein that also serves as an aryl carrier protein (ArCP) with a role in enterobactin assembly, EntB is phosphopantetheinylated near the C terminus in a reaction catalyzed by EntD with a k(cat) of 5 min(-1) and a K-m for apo-EntB of 6.5 mu M. This holo-EntB is then acylated with 2,3-DHB in a reaction catalyzed by EntE, previously described as the 2,3-DHB-AMP ligase, with a k(cat) of 100 min(-1) and a k(m) of