# High Field DNP and EPR in Biological Systems

> **NIH NIH R01** · MASSACHUSETTS INSTITUTE OF TECHNOLOGY · 2022 · $501,715

## Abstract

Project Summary -- EB002026
 This proposal is focused on the development of high frequency dynamic nuclear polarization (DNP)
nuclear magnetic resonance (NMR) to enhance sensitivity in NMR based structural biology experiments.
1 CW DNP at 527 GHz/800 MHz: We plan to complete development of a 527 GHz/800 MHz DNP
spectrometer. It will involve (1) completion of low temperature (LT), 3 channel MAS probes, (2) the
cryogenics for MAS at 80 K, (3) corrugated waveguide, and (4) interfacing these components with a 527
GHz tunable gyrotron. This will be the sole 527 GHz/800 MHz DNP instrument available in North America.
2. Applications to Peptides and Proteins: We plan to continue application of DNP to studies of
proteins The specific aim is to optimize the polarizing agents and NMR methodology for 2H,13C,15N labeled
amyloids, in particular tau, and to determine the structure of tau fibrils and PET imaging binding sites. We
will also determine the structure of H217O \ in fibrils with 17O DNP experiments on TTR and GNNQQNY
2 High B0 Cross Effect (CE) Polarizing Agents: We plan to develop new polarizing agents for CE
DNP at 600-800 MHz. They will use larger e--e- dipole couplings, trityl-TEMPO biradicals, and narrow line
radicals with different isotropic g-values that satisfy the cross effect matching condition.
3 Overhauser Effect (OE) DNP in Solids: We plan to develop narrow line trityl radicals with large 1H
hyperfine couplings that mediate OE DNP. The temperature, ω1S and ω0S dependence of these radicals will
be studied. In addition we will study specifically 2H labeled BDPA to determine the mechanism of the OE.
4 Pulsed DNP Experiments: The specific aim is to move pulsed DNP to 250 GHz using an EPR
spectrometer that is centered around a fast AWG, a 600-1000 watt 250 GHz gyroamplifier and a MAS probe
with a TE011 resonator and 1.3 mm rotor. We will investigate NOVEL, off resonance NOVEL, the frequency
sweep integrated solid effect (FS-ISE), and time optimized DNP (TOP DNP) as approaches for time domain
polarization transfer. We plan to develop adiabatic versions of the latter.
6 1H Detected DNP: We propose to develop methods for 1H detected DNP of 13C, 15N and 17O
resonances using a helium recirculation system that will permit ωr/2π>100 kHz at 90 K. The system will
initially use 1.3 and 0.7 rotors from ZrO2 and we will develop laser machined diamond rotors that will spin at
>100 kHz. The recirculation system will also be useful for spinning at ambient temperatures at >200 kHz.

## Key facts

- **NIH application ID:** 10413139
- **Project number:** 5R01GM132997-34
- **Recipient organization:** MASSACHUSETTS INSTITUTE OF TECHNOLOGY
- **Principal Investigator:** ROBERT Guy GRIFFIN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $501,715
- **Award type:** 5
- **Project period:** 1987-04-01 → 2023-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10413139

## Citation

> US National Institutes of Health, RePORTER application 10413139, High Field DNP and EPR in Biological Systems (5R01GM132997-34). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10413139. Licensed CC0.

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