Room-temperature ultrahigh-resolution time-of-flight neutron and X-ray diffraction studies of H/D-exchanged crambin

Abstract

The room-temperature (RT) X-ray structure of H/D-exchanged crambin is reported at 0.85 Å resolution. As one of the very few proteins refined with anisotropic atomic displacement parameters at two temperatures, the dynamics of atoms in the RT and 100 K structures are compared. Neutron diffraction data from an H/D-exchanged crambin crystal collected at the Protein Crystallography Station (PCS) showed diffraction beyond 1.1 Å resolution. This is the highest resolution neutron diffraction reported to date for a protein crystal and will reveal important details of the anisotropic motions of H and D atoms in protein structures.

Direct observation of hydrogen atom dynamics and interactions by ultrahigh resolution neutron protein crystallography

“…From our maps truncating the data, it appears that a resolution of 2.0 Å or better is necessary to unambiguously orient waters, and that 1.5 Å resolution or better can clearly resolve individual H atoms. In contrast, with the 0.85 Å RT X-ray data, less than 50% of H atoms in the protein, and none in the ordered solvent, were visible in F o -F c difference maps (24). Perdeuteration, when practical, increases the visibility of D atom positions at lower resolutions (35)(36)(37)).…”

“…A neutron diffraction dataset of high completeness and ultrahigh resolution (1.1 Å) was collected on a single, 4 mm 3 crystal of H/D exchanged crambin at the Protein Crystallography Station (PCS) at the Los Alamos Neutron Science Center (LANSCE). Phases from our previously reported 0.85 Å room temperature (RT) X-ray structure of H/D exchanged crambin were used as a starting model for the refinement (23,24). After initial joint X-ray/ neutron refinement in nCNS at 1.5 Å, the model was then refined in SHELX-97 against the full 1.1 Å neutron dataset alone, to a final R free ∕R1 of 0.254∕0.211 for all data (0.217∕0.170 for F o > 4σ) ( Table S1).…”

“…Data were collected at the PCS at the spallation neutron source at LANSCE. Data collection statistics were reported previously and are summarized in Table S1 (24). Forty-four settings were used to collect neutron diffraction data from a single crystal of crambin (4 mm 3 ) that were exchanged against perdeuterated synthetic mother liquor.…”

Tungsten Nitride for Capacitive Energy Storage

“…It can be seen clearly in Figure 6b that both the energy densities and power densities of the Fe(NO 3 ) 3 //Fe(NO 3 ) 3 , [41] the Ag-Mn 3 O 4 /AC//Ag-Mn 3 O 4 /AC, [42] the Fe 3 O 4 -graphene//Fe 3 O 4 -graphene, [43] the MoWN//MoWN, [44] the VN//NiO [45] and the symmetric AC//AC are inferior to the W 2 N//W 2 N, which exhibits an underlying application value of the W 2 N powder. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57…”

Application of profile fitting method to neutron time-of-flight protein single crystal diffraction data collected at the iBIX

“…STARGazer12, d*TREK modified for wavelength-resolved Laue neutron crystallography13, and Mantid14 are used at iBIX, PCS, and MaNDi, respectively. Overall, the data quality indices R merge and R pim 15 of TOF NPC diffraction data are higher than monochromatic synchrotron X-ray and nuclear reactor neutron diffraction data161718192021222324. In comparison to monochromatic synchrotron X-ray and nuclear reactor neutron diffraction data, the data processing TOF NPC diffraction data can be improved, and the lowering of R merge and R pim is a common problem in all neutron TOF single-crystal diffractometers.…”