Rhodobacter sphaeroides CryB is a bacterial cryptochrome with (6–4) photolyase activity
Rhodobacter sphaeroides CryB is a bacterial cryptochrome with (6–4) photolyase activity
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球形红细菌 CryB 是一种具有 (6â4) 光裂合酶活性的细菌隐花色素
DOI：
10.1111/febs.13924
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Klug G.
中科院分区：
文献类型：
--
作者：
von Zadow;Ignatz;Pokorny;Klug G.
光解酶是一种高效的DNA修复酶，在依赖于光的裂解反应中特异性地修复环丁烷嘧啶二聚体或（6-4）光产物。密切相关的经典隐色素蓝光光感受器不能修复DNA损伤；相反，他们参与了监管程序。CryB ofRhodobacter sphaeroideswas直到现在称为隐花色素影响光的依赖和单线态氧的相关基因表达和不同寻常的代数余子式构图。在这里，我们提出了CryB对（6-4）光产物的修复活性的证据，并提出了隐色素和光分解酶功能的双重特征。我们研究了参与辅助因子或DNA损伤结合的关键氨基酸对紫外线照射后细胞光依赖性恢复的影响（体内光再激活）。值得注意的是，两种光吸收辅助因子之一FAD或6,7‐二甲基‐8‐ribityllumazine的损伤仅轻微影响最终存活率，但强烈地减慢了光再活化动力学。通过诱变使CryB依赖性光活化降低到∆CryB敲除菌株的水平。第三个辅助因子，一个[4Fe4S]铁硫簇，对于蛋白质的结构完整性是必不可少的。通过保守的色氨酸W338来减少FAD，这对于体外还原和DNA修复是至关重要的，但对于体内光活化是不需要的，这表明这种减少FAD的途径在细胞环境中是不可缺少的。这表明体外实验只能提供有限的关于体内溶酶活性的信息。
Photolyases are efficient DNA repair enzymes that specifically repair either cyclobutane pyrimidine dimers or (6–4) photoproducts in a light‐dependent cleavage reaction. The closely related classical cryptochrome blue light photoreceptors do not repair DNA lesions; instead they are involved in regulatory processes. CryB ofRhodobacter sphaeroideswas until now described as a cryptochrome that affects light‐dependent and singlet oxygen‐dependent gene expression and is unusual in terms of its cofactor composition. Here we present evidence for a repair activity of (6–4) photoproducts by CryB and suggest a dual character combining the functions of cryptochromes and photolyases. We investigated the effects of crucial amino acids involved in cofactor or DNA lesion binding on the light‐dependent recovery of cells after UV light exposure (in vivophotoreactivation). Remarkably, impairment of one of the two light absorbing cofactors, FAD or 6,7‐dimethyl‐8‐ribityllumazine, only marginally affected the final survival rate but strongly decelerated photoreactivation kinetics. The impairment of both of them together through mutagenesis decreased CryB‐dependent photoreactivation to the level of the ∆cryBknockout strain. The third cofactor, a [4Fe4S] iron–sulfur cluster, is indispensable for the structural integrity of the protein. The reduction of FAD via the conserved tryptophan W338, which is crucial forin vitroreduction and consequently DNA repair, is not required forin vivophotoreactivation, suggesting that this reduction pathway to FAD is dispensable in the cellular environment. This demonstrates thatin vitroexperiments give only limited information onin vivophotolyase activity.
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DOI：
10.1039/c4cp05286b
发表时间：
2015-05-14
期刊：
Physical chemistry chemical physics : PCCP
影响因子：
--
作者：
Liu Z;Wang L;Zhong D
通讯作者：
Zhong D
影响因子：
2.9
作者：
LI, YF;HEELIS, PF;SANCAR, A
通讯作者：
SANCAR, A
果蝇隐花色素的光信号传导机制
影响因子：
4.8
作者：
Nuri Ozturk;C. Selby;D. Zhong;A. Sancar
通讯作者：
A. Sancar
FAD 和 8-羟基-5-脱氮黄素发色团在 Anacystis nidulans DNA 光裂合酶光活化中的作用。
DOI：
--
发表时间：
1992
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Malhotra,K;Kim,ST;Walsh,C;Sancar,A
通讯作者：
Sancar,A
影响因子：
3.7
作者：
Frühwirth S;Teich K;Klug G
通讯作者：
Klug G