Identifying, studying and making good use of macromolecular crystals

Abstract

Structural biology has contributed tremendous knowledge to the understanding of life on the molecular scale. The Protein Data Bank, a depository of this structural knowledge, currently contains over 100 000 protein structures, with the majority stemming from X-ray crystallography. As the name might suggest, crystallography requires crystals. As detectors become more sensitive and X-ray sources more intense, the notion of a crystal is gradually changing from one large enough to embellish expensive jewellery to objects that have external dimensions of the order of the wavelength of visible light. Identifying these crystals is a prerequisite to their study. This paper discusses developments in identifying these crystals during crystallization screening and distinguishing them from other potential outcomes. The practical aspects of ensuring that once a crystal is identified it can then be positioned in the X-ray beam for data collection are also addressed.

The detection and subsequent volume optimization of biological nanocrystals

“…We have not studied nanocrystals as they grow; details of the various techniques to follow this are presented elsewhere 5 . However, we have determined how often they occur compared to microcrystals.…”

“…Visual microscopy can be used to identify crystals, but has a size limit of a few microns, which limits addressing these questions. Other techniques including light-scattering and electron microscopy are available and are discussed in detail elsewhere 5 . The technical questions we have posed are general; for specific samples they can be answered in detail, but for a generally applicable answer a large number of different macromolecular samples need to be studied.…”

Time-Dependent Multi-Light-Source Image Classification Combined With Automated Multidimensional Protein Phase Diagram Construction for Protein Phase Behavior Analysis

“…Protein phase behavior plays an important role in various sectors of the biopharmaceutical field. Knowledge on protein phase behavior indirectly aids in unraveling protein's 3-dimensional structure which requires a crystalline phase, 1,2 but is also essential for downstream processing 3 and formulation development. 4,5 Protein phase behavior is often characterized with protein phase diagrams, which are used as a source of information on protein solubility, 6 insoluble aggregate morphology, [7][8][9] and aggregation kinetics.…”

Crystal Growth of High-Quality Protein Crystals under the Presence of an Alternant Electric Field in Pulse-Wave Mode, and a Strong Magnetic Field with Radio Frequency Pulses Characterized by X-ray Diffraction

“…That is why just a few 3D structures using neutron diffraction have been deposited in the Protein Data Bank (PDB). Despite these apparent disadvantages, there have been recent significant advances, not only in the beam lines and the detectors technology, but also in the sample preparation (perdeuteration), though the second via to obtain the 3D structure from nanocrystals is the free-electron lasers to perform X-ray crystallography of macromolecular complexes [6][7][8][9][10][11][12]. Additionally, magnetic fields [13][14][15][16][17][18], electric fields [16,19,20] or a combination of both [21] have proven to be efficient in obtaining bigger and higher-quality protein single crystals for X-ray crystallography.…”