Chlamydomonas reinhardtii mutants deficient for Old Yellow Enzyme 3 exhibit increased photooxidative stress.
Chlamydomonas reinhardtii mutants deficient for Old Yellow Enzyme 3 exhibit increased photooxidative stress.
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老黄酶（OYEs）是一种含黄素的烯还原酶，在可持续化学合成的生物技术潜力方面得到了广泛的研究。OYE编码基因在生命的各个领域都有发现，但它们的生理作用大多是未知的，其中一个原因是迄今为止研究的大多数烯还原酶的滥交。单细胞绿藻莱茵衣藻（Chlamydomonas reinhardtii）拥有4个编码OYEs的基因，其中3个我们之前已经进行过生化分析。烯还原酶CrOYE3表现出异常狭窄的底物范围，并以高速率转化N -甲基马来酰亚胺（NMI）。这在C. reinhardtii croye3突变体中得到了再现，与野生型相比，在外部添加NMI后几乎没有降解。我们发现CrOYE3介导的NMI转换依赖于光系统II （PSII）光合作用产生的电子，并且CrOYE3突变体在强光下表现出轻微的光化学猝灭。非光化学猝灭在该突变体中受到强烈损害，并表现出增强的氧化应激。该突变体的表型表明，C. reinhardtii CrOYE3参与了抗光氧化应激的保护，可能是通过转化来自脂质过氧化物或四吡啶降解的马来酰亚胺的活性羰基物质。
Old Yellow Enzymes (OYEs) are flavin‐containing ene‐reductases that have been intensely studied with regard to their biotechnological potential for sustainable chemical syntheses. OYE‐encoding genes are found throughout the domains of life, but their physiological role is mostly unknown, one reason for this being the promiscuity of most ene‐reductases studied to date. The unicellular green alga Chlamydomonas reinhardtii possesses four genes coding for OYEs, three of which we have analyzed biochemically before. Ene‐reductase CrOYE3 stood out in that it showed an unusually narrow substrate scope and converted N‐methylmaleimide (NMI) with high rates. This was recapitulated in a C. reinhardtii croye3 mutant that, in contrast to the wild type, hardly degraded externally added NMI. Here we show that CrOYE3‐mediated NMI conversion depends on electrons generated photosynthetically by photosystem II (PSII) and that the croye3 mutant exhibits slightly decreased photochemical quenching in high light. Non‐photochemical quenching is strongly impaired in this mutant, and it shows enhanced oxidative stress. The phenotypes of the mutant suggest that C. reinhardtii CrOYE3 is involved in the protection against photooxidative stress, possibly by converting reactive carbonyl species derived from lipid peroxides or maleimides from tetrapyrrole degradation.
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影响因子：
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作者：
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DOI：
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DOI：
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