Interaction with the small subunit of geranyl diphosphate synthase modifies the chain length specificity of geranylgeranyl diphosphate synthase to produce geranyl diphosphate
Interaction with the small subunit of geranyl diphosphate synthase modifies the chain length specificity of geranylgeranyl diphosphate synthase to produce geranyl diphosphate
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DOI：
10.1074/jbc.m105900200
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发表时间：
2002-02-01
影响因子：
4.8
通讯作者：
Croteau, R
中科院分区：
文献类型：
--
作者：
Burke, C;Croteau, R
香叶基二磷酸合酶属于异戊烯基转移酶的亚组，包括法呢基二磷酸合酶和香叶基香叶基二磷酸合酶，其催化单萜、倍半萜和二萜的相应C-10、C-15和C-20前体从C-5单元的特异性形成。与同二聚体的法呢基二磷酸合酶和香叶基香叶基二磷酸合酶不同，来自薄荷的香叶基二磷酸合酶是异四聚体，其中大亚基与植物来源的香叶基香叶基二磷酸脱氢酶共享功能基序和高水平的氨基酸序列同一性（56-75%）。然而，小亚基与其他异戊二烯基二磷酸脱氢酶几乎没有序列同一性，但它绝对是香叶基二磷酸合酶催化所必需的。在大肠杆菌中的薄荷香叶基二磷酸合酶的小亚基与来自加拿大红豆杉和冷杉的遗传学上远的香叶基香叶基二磷酸脱氢酶的共表达产生了功能性杂合异源二聚体，其在每种情况下产生香叶基二磷酸作为产物。这些结果表明，香叶基二磷酸合酶小亚基能够改变香叶基香叶基二磷酸合酶的链长特异性（但显然法呢基二磷酸合酶不能）以有利于C-10链的产生。动力学行为的父母异戊烯基转移酶与杂交酶的比较表明，杂交具有香叶基香叶基二磷酸合酶和香叶基香叶基二磷酸合酶的特性。
Geranyl diphosphate synthase belongs to a subgroup of prenyltransferases, including farnesyl diphosphate synthase and geranylgeranyl diphosphate synthase, that catalyzes the specific formation, from C-5 units, of the respective C-10, C-15, and C-20 precursors of monoterpenes, sesquiterpenes, and diterpenes. Unlike farnesyl diphosphate synthase and geranylgeranyl diphosphate synthase, which are homodimers, geranyl diphosphate synthase from Mentha is a heterotetramer in which the large subunit shares functional motifs and a high level of amino acid sequence identity (56-75%) with geranylgeranyl diphosphate synthases of plant origin. The small subunit, however, shares little sequence identity with other isoprenyl diphosphate synthases; yet it is absolutely required for geranyl diphosphate synthase catalysis. Coexpression in Escherichia coli of the Mentha geranyl diphosphate synthase small subunit with the phylogenetically distant geranylgeranyl diphosphate synthases from Taxus canadensis and Abies grandis yielded a functional hybrid heterodimer that generated geranyl diphosphate as product in each case. These results indicate that the geranyl diphosphate synthase small subunit is capable of modifying the chain length specificity of geranylgeranyl diphosphate synthase (but not, apparently, farnesyl diphosphate synthase) to favor the production of C-10 chains. Comparison of the kinetic behavior of the parent prenyltransferases with that of the hybrid enzyme revealed that the hybrid possesses characteristics of both geranyl diphosphate synthase and geranylgeranyl diphosphate synthase.