Boosting the signal of nuclear magnetic resonance spectroscopy by orders of magnitude using dissolution-DNP: biological applications, some intriguing observations, future prospects
Dynamic nuclear polarization (DNP) has been known for several decades as a particularly powerful and versatile way to enhance nuclear spin polarization, therefore sensitivity. Thus, at low temperatures, the microwave irradiation of the electron spin transition of paramagnetic impurities present in a sample of nuclear spins allows one to transfer the extremely high electron spin polarization to the nuclear spins to which they are coupled (see [1,2] for early reviews). DNP has regained interest in the early 2000’s with the invention of the coupling of DNP to the dissolution of the polarized substrate into a solution at room temperature, thereby allowing fantastic sensitivity enhancements of several orders of magnitude (~104) [3] and paving the way to a wide range of applications.
In this presentation, I will discuss selective illustrations of the applications and problems encountered
in our lab in the past few years.
DDNP has opened new avenues for the study of fast kinetic processes by NMR, and has made possible the study of fast reaction on short time scales, with a time resolution lower than the second. We have been using DDNP for the study of enzyme kinetics in solution to study reactions that take place on such time scales, which are particularly relevant for reactions in the cell. Such studies are typically beyond reach of conventional NMR techniques. Illustrations of the potential of DDNP from the study of the pentose phosphate pathway (PPP), one of the critical metabolic pathways in the cell, will be shown. The interesting case of the spontaneous rearrangement and hydrolysis of 6-phosphogluconolactone, "side-reactions" occurring in the PPP, will be discussed.[4]
On the other end of the D-DNP process, I will present observations of characteristic MASER oscillations from a sample of (frozen) water. In addition, the NMR signal was persistent for tens of seconds, when one typically expects FIDs shorter than 1 ms in these solid samples. The interpretation of these experiments in terms of the Bloch-Maxwell-Provotorov equations, [5,6] though qualitative, nevertheless provides physical insight into our observations.
References
[1] A. Abragam, M. Goldman, Rep. Prog. Phys., 41, 395, 1978
[2] V. A. Atsarkin, M. I. Rodak, Usp. Fiz. Nauk 107, 3-27, 1972
[3] J.H. Ardenkjær-Larsen, B. Fridlund, A. Gram, G. Hansson, L. Hansson, M.H. Lerche, R. Servin, M. Thaning, K. Golman, 100, 10158-10163, 2003
[4] A. Sadet, E. M.M. Weber, A. Jhajharia, D. Kurzbach, G. Bodenhausen, E. Miclet, D. Abergel, Chem. Eur.J. 24, 5456-5461, 2018
[5] P. Bösiger, E. Brun, D. Meier, Phys. Rev. A, 18, 671-684, 1978
[6] E. Weber et al., in preparation
Prof. Daniel Abergel is affiliated with the Laboratoire des biomolécules, LBM, Département de chimie, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France - Mail: daniel.abergel@ens.fr
Programm: https://chemie.univie.ac.at/en/news-events/talks-events/faculty-colloquium-series/
Fakultätskolloquium SoSe 2019 (PDF)
Bei einem nachgewiesenen Besuch von mindestens drei der vier Vorträge erhalten Studierende 0,5 ECTS für diese Lehrveranstaltung (LV 270178 SE Fakultätskolloquium).
