Powder diffraction studies on proteins: An overview of data collection approaches

Abstract

Abstract.Following the seminal work of Von Dreele, high quality powder X-ray diffraction studies on proteins are being established as a valuable complementary technique to singlecrystal measurements. Several studies using a variety of experiments approaches have been reported in the literature, including high-resolution studies employing parallel beam geometry and high intensity measurements using position sensitive detectors. The choice of the optimum instrumental configuration depends on a number of competing factors such as the amount of sample available, its radiation sensitivity, and the quality of the data required for data analysis, e.g. angular resolution, the extent of the data in d-spacing, or the number of patterns required to explore the protein's behaviour at different temperatures, or under different crystallisation conditions, etc. Here we discuss several advantages and disadvantages of different data collection methods followed for selected examples of small proteins.

Rapid screening of in cellulo grown protein crystals via a small-angle X-ray scattering/X-ray powder diffraction synergistic approach

“…During the past decade, XRPD has moved beyond fingerprinting of microcrystalline samples by extraction of accurate lattice parameters, elucidating new structural information from biological macromolecules at low and medium resolution (Von Dreele, 2019; Karavassilia & Margiolaki, 2016;Karavassili et al, 2017;Spiliopoulou et al, 2020;Margiolaki, 2019). Densely packed, randomly oriented crystals produce Debye-Scherrer rings on the detector that allow the evaluation of the diffraction capabilities of the sample (Von Dreele et al, 2000;Margiolaki et al, 2007). Even if a relatively small number (<50) of low-angle peaks is considered to be sufficient to precisely refine the unit-cell parameters (Von Dreele, 2019), the volume of the cellular soft matter that surrounds intracellular crystals significantly restricts the crystal density.…”

Preliminary insights into the non structural protein 3 macro domain of the Mayaro virus by powder diffraction

“…For the large unit cells typical of proteins, the choice of the instrumental configuration is a key issue [4]. High quality diffraction profiles, in terms of minimum peak widths to reduce peak overlap, and signal-to-noise ratio, are frequently obtained at the high resolution powder diffraction beam line ID31 at the ESRF [18].…”

“…Initial measurements were performed at ID31. Additional powder diffraction measurements on the remaining part of the material were performed on the ID11 beamline after the sample has been kept at 4 C for approximately 60 days.…”

“…Initially, microcrystals obtained in 40 drops made with 1 ml of protein and 0.5 ml of precipitation solution (imidazole malate) were gathered in a 1.0 ml tube for measurements at ID31 beamline. Additional powder diffraction measurements on the remaining part of the material were performed on ID11 beamline after the sample has been kept at 4 C for approximately 60 days. The measurements at ID31 and ID11 beamlines are presented in the next section.…”

“…It currently depends on the availability of good quality single crystals. Recent developments in X-ray powder diffraction (XPD) show that this might not always be the case [1][2][3][4][5][6], thus widening the range of proteins, which might be structurally characterized. Indeed, many macromolecules of interest do not readily form single crystals, but instead form microcrystalline powders adequate for XPD.…”