Nanometric distance measurements between Mn(ii)DOTA centers.
Nanometric distance measurements between Mn(ii)DOTA centers.
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DOI：
10.1039/c5cp03487f
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发表时间：
2015-09
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通讯作者：
H. Y. V. Ching;P. Demay-Drouhard;P. Demay-Drouhard;P. Demay-Drouhard;Hélène C. Bertrand;Hélène C. Bertrand;Hélène C. Bertrand;Clotilde Policar;Clotilde Policar;Clotilde Policar;L. C. Tabares;S. Un
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文献类型：
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作者：
H. Y. V. Ching;P. Demay-Drouhard;P. Demay-Drouhard;P. Demay-Drouhard;Hélène C. Bertrand;Hélène C. Bertrand;Hélène C. Bertrand;Clotilde Policar;Clotilde Policar;Clotilde Policar;L. C. Tabares;S. Un
脉冲电子-电子双共振（PELDOR）是一种用于探测复杂生物系统结构和功能的多功能技术。尽管最近的兴趣在高自旋金属离子的高场/频率的应用，PELDOR测量Mn（ii）仍然相对不足。在这里，我们提出了Mn（二）-Mn（二）PELDOR距离测量在94 GHz的聚脯氨酸II（PPII）螺旋双自旋标记与Mn（二）DOTA，这是区别于他们的小零场相互作用。测得的Mn-Mn距离和分布曲线与分子模型的预期值吻合良好。频域频谱中的附加特征在检测频率和泵浦频率的某些组合下变得明显。自旋哈密顿计算表明，它们可能产生的贡献，从伪长期的分量的偶极相互作用，被认为是不可忽略的Mn（ii）DOTA。然而，伪长期分量对距离分布轮廓的影响显然是有限的。结果表明，潜在的Mn（ii）DOTA自旋标记高场PELDOR距离测量蛋白质和其他生物系统。
Pulse electron-electron double resonance (PELDOR) is a versatile technique for probing the structures and functions of complex biological systems. Despite the recent interest in high-spin metal-ions for high field/frequency applications, PELDOR measurements of Mn(ii) remain relatively underexplored. Here we present Mn(ii)-Mn(ii) PELDOR distance measurements at 94 GHz on polyproline II (PPII) helices doubly spin-labeled with Mn(ii)DOTA, which are distinguished by their small zero-field interaction. The measured Mn-Mn distances and distribution profiles were in good agreement with the expected values from molecular models. Additional features in the frequency-domain spectra became apparent at certain combinations of detect and pump frequencies. Spin-Hamiltonian calculations showed that they likely arose from contributions from the pseudo-secular component of the dipolar interaction that were found to be non-negligible for Mn(ii)DOTA. However, the influence of the pseudo-secular component on the distance distribution profiles apparently was limited. The results show the potential of Mn(ii)DOTA spin labels for high-field PELDOR distance measurements in proteins and other biological systems.