Teutloff Christian, Pudollek Susanne, Kessen Sven, Broser Matthias, Zouni Athina, Bittl Robert
Fachbereich Physik, Freie Universität Berlin, Berlin, Germany.
Phys Chem Chem Phys. 2009 Aug 21;11(31):6715-26. doi: 10.1039/b908093g. Epub 2009 Jul 14.
Pulsed electron nuclear double resonance (ENDOR) spectroscopy at Q- and W-band frequencies was applied to single crystals of photosystem II from Th. elongatus. W-Band (1)H-ENDOR on the dark-stable radical state Y of the redox-active tyrosine residue Y(D) yields a complete mapping of the electronic structure of this amino acid radical in terms of an assignment of all hyperfine coupling tensors of the protons covalently bound to the side chain. This study can serve as a model case for the potential of high-field/high-frequency ENDOR on protein single crystals for obtaining highly resolved electronic structure information. Q-band (55)Mn-ENDOR was applied to the S(2) oxidation state of the water-splitting complex in photosystem II single crystals. Irrespective of the difficulties arising from the extremely broad electron paramagnetic resonance (EPR) spectroscopy ( approximately 200 mT) and ENDOR ( approximately 100 MHz) spectra a tentative assignment of the Mn ion in the formal oxidation state III to a Mn position in the structural model of PSII is possible on the basis of the ENDOR data.
将Q波段和W波段频率的脉冲电子核双共振（ENDOR）光谱应用于嗜热栖热菌光系统II的单晶。对氧化还原活性酪氨酸残基Y（D）的暗稳定自由基态Y进行W波段（1）H-ENDOR，通过对与侧链共价结合的质子的所有超精细偶合张量进行归属，得到了该氨基酸自由基电子结构的完整图谱。这项研究可作为一个模型案例，说明蛋白质单晶上的高场/高频ENDOR在获取高分辨率电子结构信息方面的潜力。将Q波段（55）Mn-ENDOR应用于光系统II单晶中析水复合物的S（2）氧化态。尽管由于极宽的电子顺磁共振（EPR）光谱（约200 mT）和ENDOR（约100 MHz）光谱带来了困难，但根据ENDOR数据，仍有可能将形式氧化态为III的锰离子初步归属到PSII结构模型中的一个锰位置。
