A prototype system for dynamically polarized neutron protein crystallography

Development of spin-contrast-variation neutron powder diffractometry for extracting the structure factor of hydrogen atoms

“…Measuring at higher proton polarization would give greater differences in peak intensities between different spin configurations, and improved neutron count rates would provide statistical significance in the analysis to determine jF H ðQÞj 2 and Re½F H ðQÞF others ðQÞ Ã . Although the opening angle of the neutron windows of approximately 120 of the new DNP apparatus is smaller than that used in previous studies [210 (Piegsa et al, 2013) and 360 (Pierce, 2017;Pierce et al, 2019)], the pulsed neutron measurements with the new DNP apparatus in J-PARC MLF seamlessly cover the Q range up to approximately 10 Å À1 . In addition, a 3 He neutron spin filter that polarizes neutrons with less than 1.0 Å was recently developed and installed in a crystal diffractometer whose resolving power is higher than that of TAIKAN (Okudaira et al, 2020).…”

Status and Outlook for the Dynamic Nuclear Polarization Program at ORNL

“…These results were consistent across all of the samples, and are also consistent with the assumed 50% initial polarization. A more thorough discussion of the results of these tests (including diffraction plots) can be found in references [4] and [10]…”

“…A prototype system for the purpose of polarizing protein crystals has been constructed and commissioned at ORNL. A full description of the device can be found in Reference [4]. A brief summary is included here.…”

“…containing 100 mM of hydroxy-TEMPO, with a goal of reaching a final concentration in the crystal similar to the TEMPO concentration used in butanol targets polarized at 5 T for nuclear physics experiments [9]. A description of the sample loading scheme can be found in Reference [4]. Figure 2: A diagram of the system in data taking mode, showing the magnet lowered to allow the neutron beam to pass over it.…”

“…DNP has been utilized in Small Angle Neuron Scattering (SANS) experiments [1] [2], and even some tests of inorganic crystals [3], but protein crystallography has not been attempted. A proof of concept system has been developed [4], and data has been taken on IMAGINE [5], a cold neutron beamline at the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) in 2017.…”