Structural and Mechanistic Studies on γ-Butyrobetaine Hydroxylase
Structural and Mechanistic Studies on γ-Butyrobetaine Hydroxylase
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DOI：
10.1016/j.chembiol.2010.09.016
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发表时间：
2010-12-22
影响因子：
--
通讯作者：
Schofield, Christopher J.
中科院分区：
文献类型：
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作者：
Leung, Ivanhoe K. H.;Krojer, Tobias J.;Schofield, Christopher J.
肉毒碱生物合成的最后一步是由γ-丁酰甜菜碱（γ BB）羟化酶（BBOX）催化的，BBOX是一种铁/2-酮戊二酸（2 OG）依赖性加氧酶。BBOX被三甲基肼-丙酸酯（THP）（一种临床使用的化合物）抑制。我们报告了BBOX及其与THP反应的结构和机理研究。晶体学和序列分析表明，BBOX和三甲基赖氨酸羟化酶形成一个亚家族的2 OG加氧酶，二聚使用的N-末端结构域。晶体结构揭示了活性位点是封闭的，以及THP如何与γ BB竞争。THP是一种底物，产生甲醛（支持与组蛋白脱甲基酶的结构连接）、二甲胺、丙二酸半醛和一种意想不到的产物，该产物具有N-脱甲基与氧化重排偶联产生的额外碳-碳键，可能通过不寻常的自由基机制。这些结果为开发改进的BBOX抑制剂提供了基础，并可能启发发现其他重排反应。
The final step in carnitine biosynthesis is catalyzed by gamma-butyrobetaine (gamma BB) hydroxylase (BBOX), an iron/2-oxoglutarate (2OG) dependent oxygenase. BBOX is inhibited by trimethylhydrazine-propionate (THP), a clinically used compound. We report structural and mechanistic studies on BBOX and its reaction with THP. Crystallographic and sequence analyses reveal that BBOX and trimethyllysine hydroxylase form a subfamily of 2OG oxygenases that dimerize using an N-terminal domain. The crystal structure reveals the active site is enclosed and how THP competes with gamma BB. THP is a substrate giving formaldehyde (supporting structural links with histone demethylases), dimethylamine, malonic acid semi-aldehyde, and an unexpected product with an additional carbon-carbon bond resulting from N-demethylation coupled to oxidative rearrangement, likely via an unusual radical mechanism. The results provide a basis for development of improved BBOX inhibitors and may inspire the discovery of additional rearrangement reactions.