Macromolecular Nanocrystal Structural Analysis with Electron and X-Rays: A Comparative Review

Abstract

Crystallography has long been the unrivaled method that can provide the atomistic structural models of macromolecules, using either X-rays or electrons as probes. The methodology has gone through several revolutionary periods, driven by the development of new sources, detectors, and other instrumentation. Novel sources of both X-ray and electrons are constantly emerging. The increase in brightness of these sources, complemented by the advanced detection techniques, has relaxed the traditionally strict need for large, high quality, crystals. Recent reports suggest high-quality diffraction datasets from crystals as small as a few hundreds of nanometers can be routinely obtained. This has resulted in the genesis of a new field of macromolecular nanocrystal crystallography. Here we will make a brief comparative review of this growing field focusing on the use of X-rays and electrons sources.

The Crystal Structure of Calcium Sebacate by X-ray Powder Diffraction Data

“…Some transition metal salts can be found in databases [22][23][24][25][26][27], but the crystallography features of calcium and sodium sebacate are totally unknown. No structures of fatty acid salts are available by transmission electron microscopy [28][29][30], a possible alternative when single crystals are not available. However, organic hydrated salts can be very unstable under an electron beam, and cryo-EM could be necessary, and therefore, X-ray powder diffraction was chosen.…”

Innovative stain-free technique for high-resolution imaging of virus particles via standard transmission electron microscopy

“…Following image configuration, we conducted SAED on these images using a single virus particle to validate the crystalline nature of the virus particles. SAED is a widely employed technique in crystallography and materials science for analyzing the structural characteristics of nanoscale particles and materials [ 15 ]. It offers valuable insights into their crystalline structure and orientation [ 16 ].…”

Towards a native environment: structure and function of membrane proteins in lipid bilayers by NMR

“…X-ray diffraction is capable of determining protein structure at a resolution higher than 2 Å, and time resolved crystallography broadens its applicability from static structure determination to investigating dynamic aspects of protein function 5 . Obtaining high quality crystals in the presence of detergent or lipid cubic phase remains challenging, however 6 . Advances in single particle cryo-EM has led to an explosion in the number of structures available for large proteins (>50 kDa) and protein complexes.…”

“… 5 Obtaining high quality crystals in the presence of detergent or lipid cubic phase remains challenging, however. 6 Advances in single particle cryo-EM has led to an explosion in the number of structures available for large proteins (>50 kDa) and protein complexes. More than 35% of the total membrane protein structures in the Protein Data Bank had been solved by cryo-EM as of 2020.…”