|
|
Open Access
Abstract: Advancements in macromolecular crystallography, driven by improved sources and cryocooling techniques, have enabled the use of increasingly smaller crystals for structure determination, with microfocus beamlines now widely accessible. Initially developed for challenging samples, these techniques have culminated in advanced beamlines such as VMXm. Here, an in vacuo sample environment improves the signal-to-noise ratio in X-ray diffraction experiments, and thus enables the use of submicrometre crystals. The advancement of techniques such as microcrystal electron diffraction (MicroED) for atomic-level insights into charged states and hydrogen positions, along with room-temperature crystallography to observe physiological states via serial crystallography, has driven a resurgence in the use of microcrystals. Reproducibly preparing small crystals, especially from samples that typically yield larger crystals, requires considerable effort, as no one singular approach guarantees optimal crystals for every technique. This review discusses methods for generating such small crystals, including mechanical crushing and batch crystallization with seeding, and evaluates their compatibility with microcrystal data-collection modalities. Additionally, we examine sample-delivery methods, which are crucial for selecting appropriate crystallization strategies. Establishing reliable protocols for sample preparation and delivery opens new avenues for macromolecular crystallography, particularly in the rapidly progressing field of time-resolved crystallography.
|
May 2025
|
|
B23-Circular Dichroism
I04-1-Macromolecular Crystallography (fixed wavelength)
I04-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
|
Open Access
Abstract: A Capillary Zone Electrophoresis (CZE) fragment screening methodology was developed and applied to the human plasma protein Transthyretin (TTR), normally soluble, but could misfold and aggregate, causing amyloidosis. Termed Free Probe Peak Height Restoration (FPPHR), it monitors changes in the level of free ligand known to bind TTR (the Probe Ligand) in the presence of competing fragments. 129 fragments were screened, 12 of the 16 initial hits (12.4% hit rate) were co-crystallised with TTR, 11 were found at the binding site (92% confirmation rate). Subsequent analogue screens have identified a novel TTR-binding scaffold 4-(3H-pyrazol-4-yl)quinoline and its derived compounds were further studied by crystallography, circular dichroism (CD), isothermal titration calorimetry (ITC) and radiolabelled 125I-Thyroxine displacement assay in neat plasma. Two lead molecules had similar ITC Kd and 125I-Thyroxine displacement IC50 values to that of Tafamidis, adding another potential pipeline for transthyretin amyloidosis. The methodology is reproducible, procedurally simple, automatable, label-free without target immobilisation, non-fluorescence based and site-specific with low false positive rate, which could be applicable to fragment screening of many drug targets.
|
May 2025
|
|
NONE-No attached Diamond beamline
|
Open Access
Abstract: We have developed sample-efficient delivery and reaction initiation strategies that use room temperature microcrystal slurries and serial crystallography methods for time-resolved studies [1-3]. However, interpreting electron density maps from reaction cycle intermediates can be challenging when mixtures of species are present in the data. Therefore, to help reduce ambiguity we and our collaborators have also pioneered strategies to simultaneously collect time-resolved serial crystallography (tr- SSX/tr-SFX) diffraction data in the forward direction, and X-ray emission spectroscopy (tr-XES) data at ∼ 90°, using either XFEL (tr-SFX) or synchrotron (tr-SSX) sources. The resulting atomic and electronic structures are fully correlated and have been applied to a range of enzymes [1, 2, 4-8]. For instance, isopenicillin N synthase (IPNS) uses nonheme iron to catalyse the O2- dependent conversion of its tripeptide substrate delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-valine (ACV) into isopenicillin N (IPN, the precursor of all penicillin/cephalosporin beta-lactam antibiotics). The unique four electron oxidation reaction leading to the beta-lactam bicyclic ring proceeds via two high-valent iron species, an Fe(III)-superoxo and a high-spin Fe(IV)=O oxyferryl species. These enable two sequential C-H bond cleavage steps that each exhibit large kinetic isotope effects (KIE). Our recent tr- SFX and tr-XES studies have characterised the Fe(III)-superoxo species and revealed unexpected, correlated motions throughout the whole protein caused by O2 binding [4].
|
Mar 2025
|
|
I13-2-Diamond Manchester Imaging
|
Diamond Proposal Number(s):
[17971]
Open Access
Abstract: We propose an imaging system and methodology for mapping soft-tissue samples in three dimensions, with micron-scale and isotropic spatial resolution, with low-concentrations as well as in the absence of heavy metal staining. We used hard x-ray phase-contrast imaging for the x-ray ability to nondestructively probe the internal structure of opaque specimens and for enhanced contrast obtained by exploiting phase effects, even in cases with reduced or absent staining agents. To demonstrate its applicability to soft-tissue specimens, we built a compact system that is easily deployable in a laboratory setting. The imaging system is based on a conventional rotating anode x-ray tube and a state-of-the-art custom-made radiation detector. The systems performance is quantitatively assessed on a calibration standard. Its potential for soft-tissue microscopy is demonstrated on two biological specimens and benchmarked against gold-standard synchrotron data. We believe that the approach proposed here can be valuable as a bridging imaging modality for intravital correlative light and electron microscopy and be applied across disciplines where the three-dimensional morphology of pristine-condition soft tissues is a key element of the investigation.
|
Jan 2025
|
|
I23-Long wavelength MX
|
Open Access
Abstract: Analytical absorption corrections are employed in scaling diffraction data for highly absorbing samples, such as those used in long-wavelength crystallography, where empirical corrections pose a challenge. AnACor2.0 is an accelerated software package developed to calculate analytical absorption corrections. It accomplishes this by ray-tracing the paths of diffracted X-rays through a voxelized 3D model of the sample. Due to the computationally intensive nature of ray-tracing, the calculation of analytical absorption corrections for a given sample can be time consuming. Three experimental datasets (insulin at λ = 3.10 Å, thermolysin at λ = 3.53 Å and thaumatin at λ = 4.13 Å) were processed to investigate the effectiveness of the accelerated methods in AnACor2.0. These methods demonstrated a maximum reduction in execution time of up to 175× compared with previous methods. As a result, the absorption factor calculation for the insulin dataset can now be completed in less than 10 s. These acceleration methods combine sampling, which evaluates subsets of crystal voxels, with modifications to standard ray-tracing. The bisection method is used to find path lengths, reducing the complexity from O(n) to O(log2 n). The gridding method involves calculating a regular grid of diffraction paths and using interpolation to find an absorption correction for a specific reflection. Additionally, optimized and specifically designed CUDA implementations for NVIDIA GPUs are utilized to enhance performance. Evaluation of these methods using simulated and real datasets demonstrates that systematic sampling of the 3D model provides consistently accurate results with minimal variance across different sampling ratios. The mean difference of absorption factors from the full calculation (without sampling) is at most 2%. Additionally, the anomalous peak heights of sulfur atoms in the Fourier map show a mean difference of only 1% compared with the full calculation. This research refines and accelerates the process of analytical absorption corrections, introducing innovative sampling and computational techniques that significantly enhance efficiency while maintaining accurate results.
|
Dec 2024
|
|
Krios I-Titan Krios I at Diamond
Krios II-Titan Krios II at Diamond
Krios IV-Titan Krios IV at Diamond
|
Jianbing
Ma
,
Gangshun
Yi
,
Mingda
Ye
,
Craig
Macgregor-Chatwin
,
Yuewen
Sheng
,
Ying
Lu
,
Ming
Li
,
Qingrong
Li
,
Dong
Wang
,
Robert J. C.
Gilbert
,
Peijun
Zhang
Diamond Proposal Number(s):
[29812]
Open Access
Abstract: The cryo-electron microscopy (cryoEM) method has enabled high-resolution structure determination of numerous biomolecules and complexes. Nevertheless, cryoEM sample preparation of challenging proteins and complexes, especially those with low abundance or with preferential orientation, remains a major hurdle. We developed an affinity-grid method employing monodispersed single particle streptavidin on a lipid monolayer to enhance particle absorption on the grid surface and alleviate sample exposure to the air-water interface. Using this approach, we successfully enriched the Thermococcus kodakarensis mini-chromosome maintenance complex 3 (MCM3) on cryoEM grids through biotinylation and resolved its structure. We further utilized this affinity method to tether the biotin-tagged dsDNA to selectively enrich a stable MCM3-ATP-dsDNA complex for cryoEM structure determination. Intriguingly, both MCM3 apo and dsDNA bound structures exhibit left-handed open spiral conformations, distinct from other reported MCM structures. The large open gate is sufficient to accommodate a dsDNA which could potentially be melted. The value of mspSA affinity method was further demonstrated by mitigating the issue of preferential angular distribution of HIV-1 capsid protein hexamer and RNA polymerase II elongation complex from Saccharomyces cerevisiae.
|
Dec 2024
|
|
|
|
Valerio
Bellucci
,
Sarlota
Birnsteinova
,
Tokushi
Sato
,
Romain
Letrun
,
Jayanath C. P.
Koliyadu
,
Chan
Kim
,
Gabriele
Giovanetti
,
Carsten
Deiter
,
Liubov
Samoylova
,
Ilia
Petrov
,
Luis
Lopez Morillo
,
Rita
Graceffa
,
Luigi
Adriano
,
Helge
Huelsen
,
Heiko
Kollmann
,
Thu Nhi
Tran Calliste
,
Dusan
Korytar
,
Zdenko
Zaprazny
,
Andrea
Mazzolari
,
Marco
Romagnoni
,
Eleni Myrto
Asimakopoulou
,
Zisheng
Yao
,
Yuhe
Zhang
,
Jozef
Ulicny
,
Alke
Meents
,
Henry N.
Chapman
,
Richard
Bean
,
Adrian
Mancuso
,
Pablo
Villanueva-Perez
,
Patrik
Vagovic
Open Access
Abstract: X-ray multi-projection imaging (XMPI) is an emerging experimental technique for the acquisition of rotation-free, time-resolved, volumetric information on stochastic processes. The technique is developed for high-brilliance light-source facilities, aiming to address known limitations of state-of-the-art imaging methods in the acquisition of 4D sample information, linked to their need for sample rotation. XMPI relies on a beam-splitting scheme, that illuminates a sample from multiple, angularly spaced viewpoints, and employs fast, indirect, X-ray imaging detectors for the collection of the data. This approach enables studies of previously inaccessible phenomena of industrial and societal relevance such as fractures in solids, propagation of shock waves, laser-based 3D printing, or even fast processes in the biological domain. In this work, we discuss in detail the beam-splitting scheme of XMPI. More specifically, we explore the relevant properties of X-ray splitter optics for their use in XMPI schemes, both at synchrotron insertion devices and XFEL facilities. Furthermore, we describe two distinct XMPI schemes, designed to faciliate large samples and complex sample environments. Finally, we present experimental proof of the feasibility of MHz-rate XMPI at the European XFEL. This detailed overview aims to state the challenges and the potential of XMPI and act as a stepping stone for future development of the technique.
|
Nov 2024
|
|
I19-Small Molecule Single Crystal Diffraction
|
Diamond Proposal Number(s):
[33014, 35357]
Open Access
Abstract: The increasing availability of ultrabright Light Sources is facilitating the study of smaller crystals at faster timescales but with an increased risk of severe X-ray damage, leading to developments in multi-crystal methods such as serial crystallography (SX). SX studies on crystals with small unit cells are challenging as very few reflections are recorded in a single data image, making it difficult to determine the orientation matrix for each crystal and thus preventing the combination of the data from all crystals for structure solution. We herein present a Small-Rotative Fixed-Target Serial Synchrotron Crystallography (SR-FT-SSX) methodology, in which rotation of the serial target through a small diffraction angle at each crystal delivers high-quality data, facilitating ab initio unit cell determination and atomic-scale structure solution. The method is benchmarked using microcrystals of the small-molecule photoswitch sodium nitroprusside dihydrate, obtaining complete data to dmin = 0.6 Å by combining just 66 partial datasets selected against rigorous quality criteria.
|
Nov 2024
|
|
B16-Test Beamline
|
Matthew
Donoghue
,
Hongchang
Wang
,
Daniel
O'Toole
,
Charles E.
Connelly
,
Shahd
Horie
,
Peter
Woulfe
,
Cornelio
Salinas
,
Brid
King
,
Brendan
Tuohy
,
Evan
Kiely
,
Kazimir
Wanelik
,
Kawal
Sawhney
,
Christoph
Kleefeld
Diamond Proposal Number(s):
[24649]
Open Access
Abstract: The study of biological soft tissue structures at the micron scale details the function of healthy and pathological tissues, which is vital in the diagnosis and treatment of diseases. Speckle based X-ray phase contrast tomographic scans at a nanometer scale have the potential to thoroughly analyse such tissues in a quantitative and qualitative manner. Diamond light source, the UKs national synchrotron facility developed and refined a 1-D X-ray speckle-based imaging technique, referred to as Fly scan mode. This novel image acquisition technique was used to perform a rapid structural composition scan of rodent lung histology samples. The rodent samples were taken from healthy and Staphylococcus aureus induced acute respiratory distress syndrome models. The analysis and cross comparison of the fly scan method, absorption-based tomography and conventional histopathology H&E staining microscopy are discussed in this paper. This analysis and cross comparison outline the ways the speckle-based technique can be of benefit. These advantages include improved soft tissue contrast, 3-D volumetric rendering, segmentation of specific gross tissue structures, quantitative analysis of gross tissue volume. A further advantage is the analysis of cellular distribution throughout the volumetric rendering of the tissue sample. The study also details the current limitations of this technique and points to ways in which future work on this imaging modality may progress.
|
Oct 2024
|
|
|
|
Abstract: Dynamic structural biology enables studying biological events at the atomic scale from 10’s of femtoseconds to a few seconds duration. With the advent of X-ray Free Electron Lasers (XFELs) and 4th generation synchrotrons, serial crystallography is becoming a major player for time-resolved experiments in structural biology. Despite significant progress, challenges such as obtaining sufficient amounts of protein to produce homogeneous microcrystal slurry, remain. Given this, it has been paramount to develop instrumentation that reduces the amount of microcrystal slurry required for experiments. Tape-drive systems use a conveyor belt made of X-ray transparent material as a motorized solid-support to steer deposited microcrystals into the beam. For efficient sample consumption on-demand ejectors can be synchronized with the X-ray pulses to expose crystals contained in droplets deposited on the tape. Reactions in the crystals can be triggered via various strategies, including pump-probe, substrate/ligand mixing, or gas incubation in the space between droplet ejection and X-ray illumination. Another challenge in time-resolved serial crystallography is interpreting the resulting electron density maps. This is especially difficult for metalloproteins where the active site metal is intimately involved in catalysis and often proceeds through multiple oxidation states during enzymatic catalysis. The unrestricted space around tape-drive systems can be used to accommodate complementary spectroscopic equipment. Here, we highlight tape-drive sample delivery systems for complementary and simultaneous X-ray diffraction (XRD) and X-ray emission spectroscopy (XES) measurements. We describe how the combination of both XRD and XES is a powerful tool for time-resolved experiments at XFELs and synchrotrons.
|
Oct 2024
|
|
