Predicting X-ray diffuse scattering from translation–libration–screw structural ensembles

Abstract

A method of simulating X-ray diffuse scattering from multi-model PDB files is presented. Despite similar agreement with Bragg data, different translation–libration–screw refinement strategies produce unique diffuse intensity patterns.

Three-dimensional crystal structure of novel aluminophosphate PST-5 solved using a powder charge flipping method

“…26 During the nal Rietveld renement, each DEA was initially considered to be rigid, and subsequently the corresponding thermal motion was described using the TLS (translation-libration-screw) method with distance restraints. 27 Thereby, the current Rietveld renement provided an R p of 8.55% and an R wp of 11.63%, with a reasonable average T-O bond distance of 1.67Å, and an average O-T-O angle of 110 . In addition, the C-N and C-C bond distances were consistent with single C-C and C-N bonds.…”

X-ray Scattering Studies of Protein Structural Dynamics

“…Nonetheless, diffuse scattering can be observed from cryo-cooled crystals. 66,74 However, significant effects of cryo-cooling on conformational equilibria have been observed. 75,76 In addition, differential contraction during cooling places strain on the crystal lattice, and can increase the apparent mosaicity of the crystal.…”

“…This approach is suitable for models based on first-principles, such as molecular dynamics simulation, or models which are fully-constrained by the Bragg data, such as uncorrelated rigid-body motions from TLS refinement. Given a structural ensemble represented by a set of Protein Data Bank (PDB) atomic coordinate files, the program phenix.diffuse 74 can be used to calculate 3D diffuse scattering maps using Guinier’s equation (Equation 96). …”

“…280 This ensemble can then be used to predict the diffuse scattering with Guinier’s formula (Equation 96). 74 …”

“…74 (A) A still diffraction image from GpdQ shows significant diffuse scattering. (B) Mode-filtered GpdQ diffraction image.…”