Geometry of hydrogen bonds formed by lipid bilayer nitroxide probes: a high-frequency pulsed ENDOR/EPR study.
Geometry of hydrogen bonds formed by lipid bilayer nitroxide probes: a high-frequency pulsed ENDOR/EPR study.
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脂质双层硝基氧探针形成的氢键的几何形状：高频脉冲 ENDOR/EPR 研究。
DOI：
10.1021/ja068395v
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发表时间：
2007
影响因子：
15
通讯作者：
Poluektov,OlegG
中科院分区：
文献类型：
--
作者：
Smirnova,TatyanaI;Smirnov,AlexI;Paschenko,SergueiV;Poluektov,OlegG
溶剂对氮氧自旋标记物磁性参数的影响结合侧向自旋标记EPR方法为阐明脂质双层中的极性分布和映射复杂生物分子系统中的局部静电效应提供了非常有用的手段。这些溶剂效应的一个主要贡献者是氮氧部分与水和/或可用的羟基之间可能形成的氢键。在这里，形成之间的氢键的脂质双层自旋探针5-doxyl硬脂酸，5DSA和氢键供体已被研究使用高频（HF）脉冲ENDOR和EPR。一个氢键氘直接检测到在HF ENDOR（130 GHz）光谱5DSA溶解在几个氘代醇，而在非极性甲苯-d8的特征信号是不存在的。氢键的长度，1.74 ± 0.06 π，其几何形状被发现是基本上相同的所有四种醇的研究，表明几乎相同的氢键已经形成，而不管溶剂的介电常数。这加强了一个假设，即HF EPR光谱是专门敏感的氢键的形成，并可用于探测复杂的生物分子组装和脂质双层与定点自旋标记方法的氢键网络。
Solvent effects on magnetic parameters of nitroxide spin labels in combination with side-directed spin-labeling EPR methods provide very useful means for elucidating polarity profiles in lipid bilayers and mapping local electrostatic effects in complex biomolecular systems. One major contributor to these solvent effects is the hydrogen bonds that could be formed between the nitroxide moiety and water and/or the available hydroxyl groups. Here, formation of hydrogen bonds between a lipid bilayer spin probe5-doxyl stearic acid, 5DSAand hydrogen-bond donors has been studied using high-frequency (HF) pulsed ENDOR and EPR. A hydrogen-bonded deuteron was directly detected in HF ENDOR (130 GHz) spectra of 5DSA dissolved in several deuterated alcohols, while the characteristic signal was absent in nonpolar toluene-d8. The length of the hydrogen bond, 1.74 ± 0.06 Å, and its geometry were found to be essentially the same for all four alcohols studied, indicating that nearly identical hydrogen bonds have been formed regardless of the solvent dielectric constant. This strengthens a hypothesis that HF EPR spectra are exclusively sensitive to formation of hydrogen bonds and could be used for probing the hydrogen-bond network in complex biomolecular assemblies and lipid bilayers with site-directed spin-labeling methods.