Measurements of 13C Multiple-Quantum Coherences in Amyloid Fibrils under Magic-Angle Spinning

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• 作者：Fang-Chieh Chou ; Tim W. T. Tsai ; Hsin-Mei Cheng ; Jerry C. C. Chan
• 刊名：The Journal of Physical Chemistry B
• 出版年：2012
• 出版时间：June 21, 2012
• 年：2012
• 卷：116
• 期：24
• 页码：7162-7167
• 全文大小：286K
• 年卷期：v.116,no.24(June 21, 2012)
• ISSN：1520-5207

文摘

The excitation and detection of high-order multiple quantum coherences among ¹³C nuclear spins are demonstrated in the samples of [1-¹³C]-class="smallcaps">l-alanine and ¹³C labeled amyloid fibrils at a spinning frequency of 20 kHz. The technique is based on the double-quantum average Hamiltonian prepared by the DRAMA-XY4 pulse sequence. Empirically, we find that multiple supercycles are required to suppress the higher-order effects for real applications. Measurements for the fibril samples formed by the polypeptides of PrP(113鈥?27) provide the first solid-state NMR evidence for the stacking of multiple 尾-sheet layers at the structural core of amyloid fibrils