A comprehensive analysis of the geranylgeranylglyceryl phosphate synthase enzyme family identifies novel members and reveals mechanisms of substrate specificity and quaternary structure organization
A comprehensive analysis of the geranylgeranylglyceryl phosphate synthase enzyme family identifies novel members and reveals mechanisms of substrate specificity and quaternary structure organization
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DOI：
10.1111/mmi.12596
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发表时间：
2014-05-01
影响因子：
3.6
通讯作者：
Babinger, Patrick
中科院分区：
文献类型：
--
作者：
Peterhoff, David;Beer, Barbara;Babinger, Patrick
香叶基香叶基甘油磷酸合酶（GGGPS）家族酶催化甘油-1-磷酸和聚异戊二烯二磷酸之间醚键的形成。它们对于古细菌膜脂的生物合成是必不可少的，但也存在于细菌物种中，尽管具有未知的生理功能。目前已知GGGPS家族酶存在两个系统发生群（I和II），但缺乏全面的研究。因此，我们通过应用序列相似性网络可视化了家族内的变异性，并对17种代表性GGGPS家族酶的催化活性和底物特异性进行了生物化学表征。此外，我们提出了第二组古细菌和细菌酶的第一个晶体结构。我们的分析表明，以前未表征的细菌酶组II具有GGGPS活性一样的古细菌酶，并不同于细菌组I的酶，是heptaprenylglyceryl磷酸脱氢酶。在II组GGGPS酶中，类异戊二烯底物的长度由与I组酶中不同的限制性残基决定，如定点诱变所示。大多数II组酶形成六聚体。我们可以通过突变作为芳香锚的单个氨基酸来将这些六聚体破坏为稳定且具有催化活性的二聚体。
Geranylgeranylglyceryl phosphate synthase (GGGPS) family enzymes catalyse the formation of an ether bond between glycerol-1-phosphate and polyprenyl diphosphates. They are essential for the biosynthesis of archaeal membrane lipids, but also occur in bacterial species, albeit with unknown physiological function. It has been known that there exist two phylogenetic groups (I and II) of GGGPS family enzymes, but a comprehensive study has been missing. We therefore visualized the variability within the family by applying a sequence similarity network, and biochemically characterized 17 representative GGGPS family enzymes regarding their catalytic activities and substrate specificities. Moreover, we present the first crystal structures of group II archaeal and bacterial enzymes. Our analysis revealed that the previously uncharacterized bacterial enzymes from group II have GGGPS activity like the archaeal enzymes and differ from the bacterial group I enzymes that are heptaprenylglyceryl phosphate synthases. The length of the isoprenoid substrate is determined in group II GGGPS enzymes by limiter residues' that are different from those in group I enzymes, as shown by site-directed mutagenesis. Most of the group II enzymes form hexamers. We could disrupt these hexamers to stable and catalytically active dimers by mutating a single amino acid that acts as an aromatic anchor'.