The amino-terminal conserved domain of 4-hydroxy-3-methylbut-2-enyl diphosphate reductase is critical for its function in oxygen-evolving photosynthetic organisms
The amino-terminal conserved domain of 4-hydroxy-3-methylbut-2-enyl diphosphate reductase is critical for its function in oxygen-evolving photosynthetic organisms
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DOI：
10.4161/15592324.2014.988072
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发表时间：
2015-01-01
影响因子：
2.9
通讯作者：
Hsieh, Ming-Hsiun
中科院分区：
文献类型：
--
作者：
Hsieh, Wei-Yu;Hsieh, Ming-Hsiun
4-羟基-3-甲基丁-2-烯基二磷酸还原酶（HDR），又称类异戊二烯合成酶H （IspH）或耐裂解酶B (LytB)，催化甲基赤藓糖醇磷酸途径的最后一步合成二磷酸异戊烯基和二磷酸二甲基烯基。IspH的结构和反应机理在大肠杆菌中研究较多，但在植物中尚不清楚。与细菌的IspH相比，蓝藻和植物的hdr都含有一个额外的n端保守结构域（NCD），这对它们的功能至关重要。NCD中的Tyr72和中心活性位点周围的几个植物特异性残基对拟南芥HDR功能至关重要。这些结果表明，植物和细菌之间HDR/IspH的结构和反应机制可能不同。大肠杆菌IspH是一种对氧敏感的铁硫蛋白。蓝藻的HDR可能是从原核生物的共同祖先独立进化而来的，从而获得NCD，这可能保护酶在光合作用过程中不受高浓度氧的影响。
4-hydroxy-3-methylbut-2-enyl diphosphate reductase (HDR), also known as isoprenoid synthesis H (IspH) or lysis-tolerant B (LytB), catalyzes the last step of the methylerythritol phosphate pathway to synthesize isopentenyl diphosphate and dimethylallyl diphosphate. The structure and reaction mechanism of IspH have been actively investigated in Escherichia coli but little is known in plants. Compared with the bacterial IspH, cyanobacterial and plant HDRs all contain an extra N-terminal conserved domain (NCD) that is essential for their function. Tyr72 in the NCD and several plant-specific residues around the central active site are critical for Arabidopsis HDR function. These results suggest that the structure and reaction mechanism of HDR/IspH may be different between plants and bacteria. The E. coli IspH is an iron-sulfur protein that is sensitive to oxygen. It is possible that the cyanobacterial HDR may independently evolve from the common ancestor of prokaryotes to obtain the NCD, which may protect the enzyme from high concentration of oxygen during photosynthesis.