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This workshop presentation discusses the use of high-resolution indirect detection techniques on water resonance, such as CEST, FLEX, and HetFLEX, with applications in NMR spectroscopy. The presentation also covers methods for denoising, random quadrature detection, and reference deconvolution.
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High Resolution Indirect Detection of NMR Spectra on a Water Resonance Mihajlo Novakovic Frydman Group – Weizmann Institute NMRbox Workshop Weizmann Institute of Science November 29, 2017
CEST – Chemical Exchange Saturation Transfer Van Zijl, P. C. M.; Yadav, N. N. Magn. Reson. Med.2011, 65, 927.
FLEX –A Fourier-based alternative to CEST Garcia, S.; Chavez, L.; Lowery, T. J.; Han, S. I.; Wemmer, D. E.; Pines, A. J. Magn. Reson. 2007, 184 (1), 72. Yadav, N. N. Magn. Reson. Med.2012, 68, 1048.
FLEX – The shift of a labile proton modulating the amplitude of the water resonance
FLEX’s superior resolution over CEST • Obtained with the same digital resolution • CEST: 1H-1H coupling
These principles can be extended to detect magnified signals from heteronuclei bound to the labile hydrogens: HetFLEX HetFLEX HMQC Read pulse on the water
Even further away from the labile protons (1): Relayed HomoFLEX The general scheme M. Novakovic, R. P. Martinho, G. L. Olsen, M. S. Lustig and L. Frydman, Phys. Chem. Chem. Phys., 2017, 24–26.
Even further away from the labile protons (2): Relayed HeteroFLEX The general scheme M. Novakovic, R. P. Martinho, G. L. Olsen, M. S. Lustig and L. Frydman, Phys. Chem. Chem. Phys., 2017, 24–26.
Water-detected 13C NMR spectroscopy After subtracting water Water resonance in DMSO 6 D-Glucose 25% uniformly labeled 20% H2O, 80% DMSO 5 4 3 2 1
NUS – solution for a slow t1 nature • Cadzow algorithm • Exponentially biased sampling • Random Quadrature Detection (RQD): goodbye to States-TPPI • At the same time provides denoising J. Gillard, Stat. Interface, 2010, 3, 335–343. P. J. Shin, P. E. Z. Larson, M. A. Ohliger, M. Elad, J. M. Pauly, D. B. Vigneronand M. Lustig, Magn. Reson. Med., 2014, 72, 959–970. M. J. Bostock, D. J. Holland and D. Nietlispach, J. Biomol. NMR, 2017, 68, 67–77. M. W. Maciejewski, M. Fenwick, A. D. Schuyler, A. S. Stern, V. Gorbatyuk and J. C. Hoch, Proc. Natl. Acad. Sci., 2011, 108, 16640–16644. M. Mobli and J. C. Hoch, Prog. Nucl. Magn. Reson. Spectrosc., 2014, 83, 21–41.
Setting up a schedule Points to acquire Real quadrature point 8.9 % subset Imaginary quadrature point 1 0. 9 0. 8 0. 7 0. 6 0. 5 0. 4 * 0. 3 * 0. 2 * 0. 1 * * * * 0 240 0 200 40 80 120 160 t increment 1
Diagram of iterative reconstruction rank-deficient
NUS performance on simulated spectra with added t1 noise Fully sampled - 256 complex points using STATES procedure NUS sampled – real and/or imaginary points extracted without quadrature 3.3 % subset 1.5 % subset 5.5 % subset 8.4 % subset 9.9 % subset 19.5 % subset
NUS REFLEX in experiments 13C natural abundance sucrose 25% 13C uniformly labeled Glucose
Benefits of random quadrature detection (RQD) 1 13C labeled Glucose 14 complex points acquired 20 RQ points acquired
Reference deconvolution - solution for a strong correlated t1 noise Standard reference signal ZF Raw FID LB, BC, F T , PH + Hilbert Processed signal FID x Mirrored FID iFT(Re) transform Hilbert Mirrored reference FID Reference FID transform iFT(Re) / Modelled reference FID Modelled reference spectrum iF T Complex ratio Processed signal FID Corrected spectrum F T x
Deconvolution of unwanted signal First t1 increment in HMQC of natural abundance menthol Reference Reference
Removing t1 noise – Reference deconvolution on nat. ab. HMQC Natural abundance Menthol
Removing t1 noise – Reference deconvolution on nat. ab. HMQC-TOCSY Natural abundance Menthol
Removing t1 noise – Reference deconvolution in FLEX Amine 1Hs of Alanine detected in water
Removing t1 noise – Reference deconvolution in HetFLEX Amine 15N of Alanine detected in water
Acknowledgements Prof. Lucio Frydman Mike Jaroszewicz Ricardo P. Martinho Dr. Gregory L. Olsen KobyZibzener