期刊
JOURNAL OF PHYSICAL CHEMISTRY B
卷 121, 期 1, 页码 47-57出版社
AMER CHEMICAL SOC
DOI: 10.1021/acs.jpcb.6b09600
关键词
-
资金
- Deutsche Forschungsgemeinschaft [SFB1078 A2, Hu702/8, Mr81/3-1]
Phytochromes are biological red/far-red light sensors found in many organisms. Photoisomerization of the linear methine-bridged tetrapyrrole triggers transient proton translocation events in the chromophore binding pocket (CBP) leading to major conformational changes of the protein matrix that are in turn associated with signaling. By combining pH-dependent resonance Raman and UV-visible absorption spectroscopy, we analyzed protonation-dependent equilibria in the CBP of Cphl involving the proposed Pr-I and Pr-II substates that prevail below and above pH 7.5, respectively. The protonation pattern and vibrational properties of these states were further characterized by means of hybrid quantummechanics/mole,cular mechanics calculations. From this combined experimental-theoretical study, we were able to identify His260 as the key residue controlling pH-dependent equilibria. This residue is not only responsible for the conformational heterogeneity of CBP in the Pr state of prokaryotic phytochromes, discussed extensively in the past, but it constitutes the sink and source of protons in the proton release/uptake mechanism involving the tetrapyrrole chromophore which finally leads to the formation of the Pfr state. Thus, this work provides valuable information that may guide further experiments toward the understanding of the specific role of protons in controlling structure and function of phytochromes in general.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据