Conformational heterogeneity of the Pfr chromophore in plant and cyanobacterial phytochromes.
Conformational heterogeneity of the Pfr chromophore in plant and cyanobacterial phytochromes.
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DOI：
10.3389/fmolb.2015.00037
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发表时间：
2015
影响因子：
5
通讯作者：
Hildebrandt P
中科院分区：
文献类型：
--
作者：
Velazquez Escobar F;von Stetten D;Günther-Lütkens M;Keidel A;Michael N;Lamparter T;Essen LO;Hughes J;Gärtner W;Yang Y;Heyne K;Mroginski MA;Hildebrandt P
光敏色素是生物光感受器，其可以在暗态和光活化态之间可逆地光转换。四吡咯辅因子在植物和蓝藻中分别是光敏色素移动素（PΦB）和藻蓝胆素（PCB），其光异构化引发了潜在的反应序列。两种状态之间的转换表示输出模块的接通/断开开关激活或去激活下游生理过程。此外，光活化状态，即，典型光敏色素中的Pfr可以热还原到暗态（Pr）。本研究旨在通过振动光谱技术分析辅因子结构，提高我们对各种PΦB-和PCB-结合光敏色素在Pfr态的特异性反应性的理解。共振拉曼（RR）光谱显示两个Pfr构象（Pfr-I和Pfr-II）形成的温度依赖性的构象平衡。这两个子状态-发现在所有的光敏色素研究，虽然有不同的相对贡献-不同的C-D和A-B次甲基桥的结构细节。在Pfr-I子状态下，环C和D之间的扭转大约。与Pfr-II相比为10°。这种结构差异可能与不同的氢键相互作用的环D所揭示的时间分辨红外光谱研究的蓝藻光敏色素Cph 1。两个子状态之间的转换显然太快（即，纳秒时间尺度），以通过NMR光谱法分辨，其不能检测Pfr中发色团的结构异质性。本研究结果的PFR状态的黑暗逆转的影响进行了讨论。
Phytochromes are biological photoreceptors that can be reversibly photoconverted between a dark and photoactivated state. The underlying reaction sequences are initiated by the photoisomerization of the tetrapyrrole cofactor, which in plant and cyanobacterial phytochromes are a phytochromobilin (PΦB) and a phycocyanobilin (PCB), respectively. The transition between the two states represents an on/off-switch of the output module activating or deactivating downstream physiological processes. In addition, the photoactivated state, i.e., Pfr in canonical phytochromes, can be thermally reverted to the dark state (Pr). The present study aimed to improve our understanding of the specific reactivity of various PΦB- and PCB-binding phytochromes in the Pfr state by analysing the cofactor structure by vibrational spectroscopic techniques. Resonance Raman (RR) spectroscopy revealed two Pfr conformers (Pfr-I and Pfr-II) forming a temperature-dependent conformational equilibrium. The two sub-states—found in all phytochromes studied, albeit with different relative contributions—differ in structural details of the C-D and A-B methine bridges. In the Pfr-I sub-state the torsion between the rings C and D is larger by ca. 10° compared to Pfr-II. This structural difference is presumably related to different hydrogen bonding interactions of ring D as revealed by time-resolved IR spectroscopic studies of the cyanobacterial phytochrome Cph1. The transitions between the two sub-states are evidently too fast (i.e., nanosecond time scale) to be resolved by NMR spectroscopy which could not detect a structural heterogeneity of the chromophore in Pfr. The implications of the present findings for the dark reversion of the Pfr state are discussed.
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影响因子：
21.8
作者：
Escobar, Francisco Velazquez;Piwowarski, Patrick;Hildebrandt, Peter
通讯作者：
Hildebrandt, Peter
DOI：
10.1107/s0907444912020537
发表时间：
2012-08-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY
影响因子：
--
作者：
Bellini, Dom;Papiz, Miroslav Z.
通讯作者：
Papiz, Miroslav Z.
影响因子：
3.8
作者：
Mroginski, M. A.;von Stetten, D.;Hildebrandt, P.
通讯作者：
Hildebrandt, P.
影响因子：
2.9
作者：
MATYSIK, J;HILDEBRANDT, P;SCHAFFNER, K
通讯作者：
SCHAFFNER, K
影响因子：
2.9
作者：
Borucki, B;Otto, H;Lamparter, T
通讯作者：
Lamparter, T