Stereoselective C3-substituent modification and substrate channeling by oxidoreductase BchC in bacteriochlorophyll a biosynthesis
Stereoselective C3-substituent modification and substrate channeling by oxidoreductase BchC in bacteriochlorophyll a biosynthesis
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细菌叶绿素 a 生物合成中氧化还原酶 BchC 的立体选择性 C3 取代基修饰和底物通道
DOI：
10.1002/1873-3468.13372
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发表时间：
2019
期刊：
影响因子：
3.5
通讯作者：
Hitoshi Tamiaki
中科院分区：
文献类型：
--
作者：
Misato Teramura;Yusuke Tsukatani;Jiro Harada;Mitsuaki Hirose;Hitoshi Tamiaki
我们报道了参与细菌-叶绿素合成的重组BchC氧化还原酶的体外活性。胶囊红杆菌的BchC优先将31R-3-(1-羟乙基)-叶绿素和31R‐3‐(1‐hydroxyethyl)‐bacteriochlorophyllideain+分别氧化为3-乙酰基叶绿素和细菌叶绿素，留下未反应的31S-异构体。在反向反应中，BchC和NADH主要从3-乙酰基(细菌)氯生成31R-表观异构醇。被盖绿杆菌的BchC表现出相同的31R-选择性，这表明在BchC催化的还原中，31R-同分异构体的利用在不同的光合细菌门之间可能是保守的。此外，在3-(1-羟乙基)-叶绿素转化为3-乙酰基叶绿素的过程中，BchC的存在加速了青绿杆菌BchF水合酶对3-乙烯基水合反应的促进，表明这些酶协同作用促进细菌-叶绿素的高效合成。
We report thein vitroactivity of recombinant BchC oxidoreductase involved in bacteriochlorophyllabiosynthesis. BchC ofRhodobacter capsulatuspreferentially oxidizes 31R‐3‐(1‐hydroxyethyl)‐chlorophyllideaand 31R‐3‐(1‐hydroxyethyl)‐bacteriochlorophyllideain the presence of NAD+to 3‐acetyl‐chlorophyllideaand bacteriochlorophyllidea, respectively, leaving the unreacted 31S‐epimers. In the reverse reaction, BchC with NADH predominately produces 31R‐epimeric alcohols from the 3‐acetyl‐(bacterio)chlorins. BchC ofChlorobaculum tepidumdemonstrates the same 31R‐selectivity, suggesting that utilization of 31R‐epimers in BchC‐catalyzed reductions may be conserved across different phyla of photosynthetic bacteria. Additionally, the presence of BchC accelerates the 3‐vinyl hydration by BchF hydratase ofChlorobaculum tepidumduring conversion of chlorophyllideato 3‐acetyl‐chlorophyllideathrough 3‐(1‐hydroxyethyl)‐chlorophyllidea, indicating that these enzymes work cooperatively to promote efficient bacteriochlorophyllabiosynthesis.