Advanced X-ray crystallography determines structure of macromolecule at unprecedented resolution
Proteins are high-performance molecular machines that carry out nearly every biochemical function inside living cells. To understand how they achieve this, scientists often examine their detailed atomic structure, which holds important clues to their activity. The more precision they achieve, the deeper the insight they may gain into the chemical principles that underlie protein structure and,…
Scientists have determined the highest-resolution structure of the archaeal rubredoxin protein using advanced X-ray crystallography techniques. This resolution, at 0.43 Å, represents the sharpest detail ever achieved in protein structure determination. The breakthrough was made possible by a combination of cutting-edge X-ray crystallography and advanced quantum-chemical models.
The research team, led by Ashwin Chari from the Max Planck Institute for Multidisciplinary Sciences, Gleb Bourenkov from EMBL Hamburg, Clemens Schulze-Briese from DECTRIS, Paulina Maria Dominiak from the University of Warsaw, and Gérard Bricogne from Global Phasing Ltd., utilized the high-intensity X-ray beam from PETRA III at DESY in Germany.
The beamline P14 at EMBL Hamburg provided a uniform, adjustable radiation intensity, known as a "top-hat" beam, which enabled precise control over the X-ray dose delivered to the protein crystal.
This "resolution-in-dose" approach, developed during previous experiments by the same team, minimizes radiation damage by collecting data at low doses on large protein crystals under a "top-hat" beam. Using the beamline P14, the scientists collected high-quality data and processed it with advanced protocols created on the fly by Global Phasing's workflow software.
This data allowed for accurate determination of atomic positions, including hydrogen atoms, and revealed quantum mechanical phenomena such as electrons at the midpoint of chemical bonds and atomic partial charges.
These findings demonstrate that traditional spherical scattering factors are insufficient for accurately modeling the electron densities at such high resolutions. Instead, the team employed aspherical scattering factors to better describe the experimental structure. This advancement in X-ray crystallography opens the door to routine quantum crystallography of biological macromolecules, with the ultimate goal of gaining deeper insights into enzyme-catalyzed reactions for advancements in chemistry, materials science, and medicine.
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