Crystal structures of cyanobacterial light-dependent protochlorophyllide oxidoreductase
Crystal structures of cyanobacterial light-dependent protochlorophyllide oxidoreductase
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DOI：
10.1073/pnas.1920244117
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发表时间：
2020-04-14
影响因子：
11.1
通讯作者：
Liu, Lin
中科院分区：
文献类型：
--
作者：
Dong, Chen-Song;Zhang, Wei-Lun;Liu, Lin
原叶绿素(Pchlide)还原为Chlide(Chlide)是叶绿素生物合成的倒数第二步。在产氧的光合作用细菌、藻类和植物中，这一反应可以由光依赖的Pchlide氧化还原酶(LPOR)催化，LPOR是短链脱氢酶超家族的成员，在NAD(P)H结合和催化活性方面共享保守的Rossmann折叠。虽然已经使用建模和模拟的方法来研究这种光驱动反应的催化机理，但LPOR结构的关键细节仍不清楚。我们测定了两种蓝藻聚球藻LPOR的晶体结构。PCC6803和长链嗜热杆菌。结构分析定义了LPOR核心折叠，概述了LPOR-NADPH相互作用网络，确定了形成底物空腔和质子中继路径的残基，并揭示了LPOR特异性环的作用。这些发现为理解光驱动的Pchlide还原的结构-功能关系提供了基础。
The reduction of protochlorophyllide (Pchlide) to chlorophyllide (Chlide) is the penultimate step of chlorophyll biosynthesis. In oxygenic photosynthetic bacteria, algae, and plants, this reaction can be catalyzed by the light-dependent Pchlide oxidoreductase (LPOR), a member of the short-chain dehydrogenase superfamily sharing a conserved Rossmann fold for NAD(P)H binding and the catalytic activity. Whereas modeling and simulation approaches have been used to study the catalytic mechanism of this light-driven reaction, key details of the LPOR structure remain unclear. We determined the crystal structures of LPOR from two cyanobacteria, Synechocystis sp. PCC 6803 and Thermosynechococcus elongatus. Structural analysis defines the LPOR core fold, outlines the LPOR-NADPH interaction network, identifies the residues forming the substrate cavity and the proton-relay path, and reveals the role of the LPOR-specific loop. These findings provide a basis for understanding the structure-function relationships of the light-driven Pchlide reduction.