TY - JOUR T1 - Measuring and modeling diffuse scattering in protein X-ray crystallography JF - bioRxiv DO - 10.1101/033746 SP - 033746 AU - Andrew H. Van Benschoten AU - Ana Gonzalez AU - Aaron S. Brewster AU - Nicholas K. Sauter AU - James S. Fraser AU - Michael E. Wall Y1 - 2015/01/01 UR - http://biorxiv.org/content/early/2015/12/07/033746.abstract N2 - X-ray diffraction has the potential to provide rich information about the structural dynamics of macromolecules. To realize this potential fully, it will be necessary to measure and model both Bragg scattering, which is currently used to derive macromolecular structures, and diffuse scattering, which reports on correlations in charge density variations. However, due to the extra effort of collecting diffuse data, experimental measurement of diffuse scattering from protein crystals has been limited to a small number of systems. Here, we present three-dimensional measurements of diffuse intensity collected from crystals of the model enzymes cyclophilin A and trypsin. The measurements were obtained from the same X-ray diffraction images as the Bragg data, using best practices for data collection in protein crystallography. To model the underlying dynamics in a practical way that can be used during structure refinement, we tested both Translation-Libration-Screw (TLS) and Liquid-Like Motions (LLM) models of protein motions. Whereas different TLS groupings yielded similar Bragg intensities, the diffuse intensities were clearly different. The agreement of the LLM models with the diffuse data was much stronger than for TLS. These results demonstrate a path to substantially increase the number of diffuse datasets available to the wider biosciences community. These and future datasets will be useful to benchmark computational tools for modeling correlated motions in macromolecules and to improve refinement of dynamics-inspired structural models emerging in X-ray crystallography.Significance The structural details of protein motions are critical to many biological processes, but they are hidden to conventional biophysical techniques. Diffuse X-ray scattering can reveal these details by measuring the correlated movements between atoms. However, diffuse scattering data collection historically has required extra effort and dedicated experimental protocols. We have measured three-dimensional diffuse intensities in X-ray diffraction from CypA and trypsin crystals using standard crystallographic data collection techniques. Analysis of the resulting data is consistent with the presence of liquid-like motions (LLM) in both crystals. Our results show that using diffuse scattering to model protein motions can become a component of routine crystallographic analysis through the extension of commonplace methods. ER -