Femto- to Microsecond Photodynamics of an Unusual Bacteriophytochrome
Femto- to Microsecond Photodynamics of an Unusual Bacteriophytochrome
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DOI：
10.1021/jz502408n
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发表时间：
2015-01-15
影响因子：
5.7
通讯作者：
Kennis, John T. M.
中科院分区：
文献类型：
--
作者：
Mathes, Tilo;Ravensbergen, Janneke;Kennis, John T. M.
橙黄柱头菌（Stigmatella aurantiaca）的细菌光敏色素是细菌光敏色素家族中一个不寻常的成员，其与胆绿素（BV）发色团的D环羰基没有氢键。BV在SaBphP 1野生型和单一突变体T289 H重新引入氢键环D的光动力学表明，这种特殊的弱相互作用的强度决定了激发态寿命，Lumi-R量子产率和光谱异质性。特别是，激发态衰减更快，在没有氢键的环D，与激发态半衰期为30和80 ps的野生型和T289 H突变体，分别。同时，与T289 H突变体相比，野生型中的Lumi-R量子产率高两倍。此外，野生型的光谱异质性显著高于T289 H突变体。通过将可观察到的时域扩展到25 μ s，我们观察到一个新的失活途径从Lumi-R中间体在100 ns的时域，对应于环D的后翻转到原来的Pr 15 Za异构态。
A bacteriophytochrome from Stigmatella aurantiaca is an unusual member of the bacteriophytochrome family that is devoid of hydrogen bonding to the carbonyl group of ring D of the biliverdin (BV) chromophore. The photodynamics of BV in SaBphP1 wild type and the single mutant T289H reintroducing hydrogen bonding to ring D show that the strength of this particular weak interaction determines excited-state lifetime, Lumi-R quantum yield, and spectral heterogeneity. In particular, excited-state decay is faster in the absence of hydrogen-bonding to ring D, with excited-state half-lives of 30 and 80 ps for wild type and the T289H mutant, respectively. Concomitantly, the Lumi-R quantum yield is two times higher in wild type as compared with the T289H mutant. Furthermore, the spectral heterogeneity in the wild type is significantly higher than that in the T289H mutant. By extending the observable time domain to 25 mu s, we observe a new deactivation pathway from the Lumi-R intermediate in the 100 ns time domain that corresponds to a backflip of ring D to the original Pr 15Za isomeric state.