Ultrafast dynamics of flavins in five redox states.
Ultrafast dynamics of flavins in five redox states.
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DOI：
10.1021/ja8045469
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发表时间：
2008-10-01
影响因子：
15
通讯作者：
Zhong, Dongping
中科院分区：
文献类型：
--
作者：
Kao, Ya-Ting;Saxena, Chaitanya;He, Ting-Fang;Guo, Lijun;Wang, Lijuan;Sancar, Aziz;Zhong, Dongping
我们在这里报告我们的系统研究的激发态动力学的两个常见的黄素分子，FMN和FAD，在五个氧化还原状态的氧化形式，中性和阴离子半醌，中性和阴离子完全还原的氢醌在溶液中，并在惰性蛋白质的环境与飞秒分辨率。使用蛋白质环境，我们能够稳定两个半醌自由基，从而观察到他们的弱发射光谱。值得注意的是，我们观察到它们的激发态动力学和平面性的黄素isoalloxazine环之间的强相关性。对于一个弯曲的环结构，我们都观察到从几个到几百皮秒的超快动力学和强烈的激发波长依赖性的发射光谱，表明在弛豫过程中失活。调用蝶形弯曲运动以接近锥形交叉点以促进去激活。这些状态包括溶液中的阴离子半醌自由基和完全还原的中性和阴离子氢醌。在平面构型中，除了FAD的堆叠构象外，黄素具有纳秒级的长寿命，其中观察到5-9 ps的环和腺嘌呤部分之间的分子内电子转移以及30-40 ps的随后的电荷重组。这些观察到的不同的动力学，控制的黄素环的灵活性，是根本的flavoenzyme的功能，如观察到的光解酶与平面结构，以延长寿命，以最大限度地提高DNA修复效率，并在昆虫1型隐花色素与灵活的结构，以改变激发态失活，以调节功能通道。
We report here our systematic studies of excited-state dynamics of two common flavin molecules, FMN and FAD, in five redox states of oxidized form, neutral and anionic semiquinones, and neutral and anionic fully-reduced hydroquinones in solution and in inert protein environments with femtosecond resolution. Using protein environments, we are able to stabilize two semiquinone radicals and thus observed their weak emission spectra. Significantly, we observed a strong correlation between their excited-state dynamics and the planarity of their flavin isoalloxazine ring. For a bent ring structure, we all observed ultrafast dynamics from a few to hundreds of picoseconds and strong excitation-wavelength dependence of emission spectra, indicating deactivation during relaxation. A butterfly bending motion is invoked to get access to conical intersection(s) to facilitate deactivation. These states include the anionic semiquinone radical and fully-reduced neutral and anionic hydroquinones in solution. In a planar configuration, flavins have a long lifetime in nanoseconds except for the stacked conformation of FAD, where the intramolecular electron transfer between the ring and the adenine moiety in 5-9 ps as well as the subsequent charge recombination in 30-40 ps were observed. These observed distinct dynamics, controlled by the flavin ring flexibility, are fundamental to flavoenzyme’s functions as observed in photolyase with a planar structure to lengthen the lifetime to maximize DNA repair efficiency and in insect Type 1 cryptochrome with a flexible structure to vary the excited-state deactivation to modulate the functional channel.
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影响因子：
3.6
作者：
Hasford, JJ;Kemnitzer, W;Rizzo, CJ
通讯作者：
Rizzo, CJ
影响因子：
--
作者：
COPELAND, RA;SPIRO, TG
通讯作者：
SPIRO, TG
影响因子：
2.2
作者：
Hahn, J;Michel-Beyerle, ME;Rosch, N
通讯作者：
Rosch, N
色氨酸7-卤代酶（PRNA）结构提出了一种区域选择性氯化的机制。
DOI：
10.1126/science.1116510
发表时间：
2005-09-30
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Dong C;Flecks S;Unversucht S;Haupt C;van Pée KH;Naismith JH
通讯作者：
Naismith JH
影响因子：
2.9
作者：
GHISLA, S;MASSEY, V;MAYHEW, SG
通讯作者：
MAYHEW, SG