Low-concentration photochemically induced dynamic nuclear polarization (LC-photo-CIDNP) has recently emerged as a powerful technology for the detection of aromatic amino acids and proteins in solution in the low-micromolar to nanomolar concentration range. LC-photo-CIDNP is typically carried out in the presence of high-power lasers, which are costly and maintenance-heavy. Here, we show that LC-photo-CIDNP can be performed with light-emitting diodes (LEDs), which are inexpensive and much less cumbersome than lasers, laser diodes, flash lamps, or other light sources. When nuclear magnetic resonance (NMR) sample concentration is within the low-micromolar to nanomolar range, as in LC-photo-CIDNP, replacement of lasers with LEDs leads to no losses in sensitivity. We also investigate the effect of optical-fiber thickness and compare excitation rate constants of an Ar ion laser (488 nm) and a 466 nm LED, taking LED emission bandwidths into account. In addition, importantly, we develop a novel pulse sequence (13C RASPRINT) to perform ultrarapid LC-photo-CIDNP data collection. Remarkably, 13C RASPRINT leads to 4-fold savings in data collection time. The latter advance relies on the fact that photo-CID nuclear hyperpolarization does not suffer from the longitudinal-relaxation recovery requirements of conventional NMR. Finally, we combine both the above improvements, resulting in facile and rapid (≈16 s–2.5 min) collection of 1 and 2D NMR data on aromatic amino acids and proteins in solution at nanomolar to low micromolar concentration.

1.
Y.
Okuno
,
M. F.
Mecha
,
H.
Yang
,
L.
Zhu
,
C. G.
Fry
, and
S.
Cavagnero
, “
Laser- and cryogenic-probe-assisted NMR enables hypersensitive analysis of biomolecules at sub-micromolar concentration
,”
Proc. Natl. Acad. Sci. U. S. A.
116
,
11602
(
2019
).
2.
H.
Yang
and
S.
Cavagnero
, “
Improved sensitivity of laser-enhanced 1Hα-13Cα-correlation via suppression of Cα-C′ scalar-coupling evolution
,”
J. Magn. Reson.
307
,
106572
(
2019
).
3.
J. H.
Lee
,
Y.
Okuno
, and
S.
Cavagnero
, “
Sensitivity enhancement in solution NMR: Emerging ideas and new frontiers
,”
J. Magn. Reson.
241
,
18
(
2014
).
4.
J. H.
Ardenkjaer-Larsen
 et al, “
Facing and overcoming sensitivity challenges in biomolecular NMR spectroscopy
,”
Angew. Chem., Int. Ed.
54
,
9162
(
2015
).
5.
R. A.
Green
,
R. W.
Adams
,
S. B.
Duckett
,
R. E.
Mewis
,
D. C.
Williamson
, and
G. G.
Green
, “
The theory and practice of hyperpolarization in magnetic resonance using parahydrogen
,”
Prog. Nucl. Magn. Reson. Spectrosc.
67
,
1
(
2012
).
6.
G.
Zhang
and
C.
Hilty
, “
Applications of dissolution dynamic nuclear polarization in chemistry and biochemistry
,”
Magn. Reson. Chem.
56
,
566
(
2018
).
7.
P. J.
Rayner
and
S. B.
Duckett
, “
Signal amplification by reversible exchange (SABRE): From discovery to diagnosis
,”
Angew. Chem., Int. Ed.
57
,
6742
(
2018
).
8.
P. J.
Hore
and
R. W.
Broadhurst
, “
Photo-CIDNP of biopolymers
,”
Prog. Nucl. Magn. Reson. Spectrosc.
25
,
345
(
1993
).
9.
J.
Bargon
,
H.
Fischer
, and
U.
Johnsen
, “
Nuclear magnetic resonance emission lines during fast radical reactions. I. Recording methods and examples
,”
Z. Naturforsch., A: Phys. Sci.
22
,
1551
(
1967
).
10.
H. R.
Ward
and
R. G.
Lawler
, “
Nuclear magnetic resonance emission and enhanced absorption in rapid organometallic reactions
,”
J. Am. Chem. Soc.
89
,
5518
(
1967
).
11.
Y.
Okuno
and
S.
Cavagnero
, “
Fluorescein: A photo-CIDNP sensitizer enabling hypersensitive NMR data collection in liquids at low micromolar concentration
,”
J. Phys. Chem. B
120
,
715
(
2016
).
12.
J. H.
Lee
,
A.
Sekhar
, and
S.
Cavagnero
, “
1H-detected 13C photo-CIDNP as a sensitivity enhancement tool in solution NMR
,”
J. Am. Chem. Soc.
133
,
8062
(
2011
).
13.
L.
Emsley
and
G.
Bodenhausen
, “
Optimization of shaped selective pulses for NMR using a quaternion description of their overall propagators
,”
J. Magn. Reson.
97
,
135
(
1992
).
14.
J. H.
Lee
and
S.
Cavagnero
, “
A novel tri-enzyme system in combination with laser-driven NMR enables efficient nuclear polarization of biomolecules in solution
,”
J. Phys. Chem. B
117
,
6069
(
2013
).
15.
P.
Nitschke
,
N.
Lokesh
, and
R. M.
Gschwind
, “
Combination of illumination and high resolution NMR spectroscopy: Key features and practical aspects, photochemical applications, and new concepts
,”
Prog. Nucl. Magn. Reson. Spectrosc.
114-115
,
86
(
2019
).
16.
J.
Matysik
,
Alia
,
J. G.
Hollander
,
T.
Egorova-Zachernyuk
,
P.
Gast
, and
H. J. M.
de Groot
, “
A set-up to study photochemically induced dynamic nuclear polarization in photosynthetic reaction centres by solid-state NMR
,”
Indian J. Biochem. Biophys.
37
,
418
(
2000
).
17.
P.
Bielytskyi
,
D.
Gräsing
,
S.
Zahn
,
A.
Alia
, and
J.
Matysik
, “
15N–1H transfer of light-induced nuclear hyperpolarization in frozen photosynthetic reaction centers
,”
Appl. Magn. Reson.
50
,
695
(
2019
).
18.
M.
Mompean
,
R. M.
Sanchez-Donoso
,
A.
de la Hoz
,
V.
Saggiomo
,
A. H.
Velders
, and
M. V.
Gomez
, “
Pushing nuclear magnetic resonance sensitivity limits with microfluidics and photo-chemically induced dynamic nuclear polarization
,”
Nat. Commun.
9
,
108
(
2018
).
19.
C.
Feldmeier
,
H.
Bartling
,
E.
Riedle
, and
R. M.
Gschwind
, “
LED based NMR illumination device for mechanistic studies on photochemical reactions—Versatile and simple, yet surprisingly powerful
,”
J. Magn. Reson.
232
,
39
(
2013
).
20.
C.
Feldmeier
,
H.
Bartling
,
K.
Magerl
, and
R. M.
Gschwind
, “
LED-illuminated NMR studies of Flavin-catalyzed photooxidations reveal solvent control of the electron-transfer mechanism
,”
Angew. Chem., Int. Ed.
54
,
1347
(
2015
).
21.
E.
Daviso
,
A.
Diller
,
A.
Alia
,
J.
Matysik
, and
G.
Jeschke
, “
Photo-CIDNP MAS NMR beyond the T1 limit by fast cycles of polarization extinction and polarization generation
,”
J. Magn. Reson.
190
,
43
(
2008
).
22.
J. H.
Lee
,
D.
Zhang
,
C.
Hughes
,
Y.
Okuno
,
A.
Sekhar
, and
S.
Cavagnero
, “
Heterogeneous binding of the SH3 client protein to the DnaK molecular chaperone
,”
Proc. Natl. Acad. Sci. U. S. A.
112
,
E4206
(
2015
).
23.
F.
Delaglio
,
S.
Grzesiek
,
G. W.
Vuister
,
G.
Zhu
,
J.
Pfeifer
, and
A.
Bax
, “
NMRPipe: A multidimensional spectral processing system based on UNIX pipes
,”
J. Biomol. NMR
6
,
277
(
1995
).
24.
M.
Tollinger
,
N. R.
Skrynnikov
,
F. A.
Mulder
,
J. D.
Forman-Kay
, and
L. E.
Kay
, “
Slow dynamics in folded and unfolded states of an SH3 domain
,”
J. Am. Chem. Soc.
123
,
11341
(
2001
).
25.
J.
Bernarding
,
F.
Euchner
,
C.
Bruns
,
R.
Ringleb
,
D.
Muller
,
T.
Trantzschel
,
J.
Bargon
,
U.
Bommerich
, and
M.
Plaumann
, “
Low-cost LED-based photo-CIDNP enables biocompatible hyperpolarization of 19F for NMR and MRI at 7 T and 4.7 T
,”
ChemPhysChem
19
,
2453
(
2018
).
26.
I.
Kuprov
and
P. J.
Hore
, “
Chemically amplified 19F-1H nuclear Overhauser effects
,”
J. Magn. Reson.
168
,
1
(
2004
).
27.
G.
Olsen
,
E.
Markhasin
,
O.
Szekely
,
C.
Bretschneider
, and
L.
Frydman
, “
Optimizing water hyperpolarization and dissolution for sensitivity-enhanced 2D biomolecular NMR
,”
J. Magn. Reson.
264
,
49
(
2016
).
28.
A. J.
Shaka
,
P. B.
Barker
, and
R.
Freeman
, “
Computer-optimized decoupling scheme for wideband applications and low-level operation
,”
J. Magn. Reson.
64
,
547
(
1985
).
29.
E.
Gaggelli
,
G.
Valensin
,
T.
Kushnir
, and
G.
Navon
, “
Determination of absolute values of dipolar cross-relaxation rates for ligands bound to macromolecules using double-selective T1
,”
Magn. Reson. Chem.
30
,
461
(
1992
).
30.
G. W.
Vuister
and
A.
Bax
, “
Resolution enhancement and spectral editing of uniformly 13C-enriched proteins by homonuclear broadband 13C decoupling
,”
J. Magn. Reson.
98
,
428
(
1992
).
31.
P.
Schanda
and
B.
Brutscher
, “
Very fast two-dimensional NMR spectroscopy for real-time investigation of dynamic events in proteins on the time scale of seconds
,”
J. Am. Chem. Soc.
127
,
8014
(
2005
).
32.
S.
Spera
and
A.
Bax
, “
Empirical correlation between protein backbone conformation and C.alpha. and C.beta. 13C nuclear magnetic resonance chemical shifts
,”
J. Am. Chem. Soc.
113
,
5490
(
1991
).
33.
J.
Kim
,
R.
Mandal
, and
C.
Hilty
, “
Observation of fast two-dimensional NMR spectra during protein folding using polarization transfer from hyperpolarized water
,”
J. Phys. Chem. Lett.
10
,
5463
(
2019
).
34.
A.
Sadet
,
C.
Stavarache
,
M.
Bacalum
,
M.
Radu
,
G.
Bodenhausen
,
D.
Kurzbach
, and
P. R.
Vasos
, “
Hyperpolarized water enhances two-dimensional proton NMR correlations: A new approach for molecular interactions
,”
J. Am. Chem. Soc.
141
,
12448
(
2019
).
35.
O.
Szekely
,
G. L.
Olsen
,
I. C.
Felli
, and
L.
Frydman
, “
High-resolution 2D NMR of disordered proteins enhanced by hyperpolarized water
,”
Anal. Chem.
90
,
6169
(
2018
).

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