I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[40628]
Abstract: The short-range structure of the glass compositions 45SiO₂–25SrO–28Na₂O–2P₂O₅, 45SiO₂–12.5SrO–12.5CaO–28Na₂O–2P₂O₅, and 45SiO₂–25CaO–28Na₂O–2P₂O₅ was investigated using high-energy X-ray diffraction (XRD) supported by Reverse Monte Carlo (RMC) modelling and classical Molecular Dynamics (MD) simulations. Both RMC and MD models show good agreement with the experimental X-ray and published neutron diffraction S(Q), with only minor differences in average bond lengths and coordination numbers reflecting the characteristics of each approach. Consistent Si–O and P–O environments are observed across all compositions, confirming a similar short-range network structure. The modifier cations display composition-dependent variations: Na⁺ maintains a nearly constant coordination of ∼5, whereas Ca²⁺ and Sr²⁺ show distinct trends, with Ca–O distances of 2.34–2.41 Å and coordination numbers of ∼5–6, and Sr–O distances of 2.60–2.70 Å with coordination numbers of ∼4.6–5.7. The most significant structural changes arise in the mixed-modifier glass, where the coexistence of Ca and Sr results in a cooperative modifier effect evidenced by simultaneous reductions in Ca–O and Sr–O coordination and increased network disruption. This combined high-energy XRD–RMC–MD approach provides new insight into subtle modifier–modifier interactions in multicomponent bioactive glasses.
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May 2026
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Jungmin
Kang
,
Yoshiaki
Shimazu
,
Fangjia
Luo
,
Ayumi
Yamashita
,
Tomoyuki
Tanaka
,
Yuichi
Inubushi
,
Kensuke
Tono
,
Nipawan
Nuemket
,
Allen M.
Orville
,
So
Iwata
,
Eriko
Nango
,
Makina
Yabashi
Open Access
Abstract: We have developed a compact tape drive (CoT) with on-demand sample delivery for time-resolved serial femtosecond crystallography (SFX) experiments, which can deliver sample droplets and/or initiate reactions with a drop-on-drop strategy. Two disposable piezoelectric injectors are positioned in tandem along the tape to produce a queue of nanolitre-scale droplets. X-ray free-electron laser pulses arrive perpendicular to and pass through the broad face of the tape. The pulse is synchronized and aligned to the droplets, thereby enabling highly efficient SFX data collection. The tape transport speed and the delivery distance can be varied to control the mixing time from approximately 130 ms to tens of seconds. We conducted time-resolved SFX experiments utilizing a basic enzymatic reaction model of hen egg white lysozyme (HEWL) and N-acetyl-D-glucosamine (GlcNAc) to demonstrate the drop-on-drop capabilities of the CoT, and the full binding process of GlcNAc to HEWL was observed at 1.3–9.7 s.
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Apr 2026
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B21-High Throughput SAXS
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Diamond Proposal Number(s):
[29895]
Open Access
Abstract: A lipopeptide is designed that contains an epitope from simian virus T-antigen (SV40T, PKKKRKV) conjugated to an N-terminal palmitoyl (C16-) moiety, with the aim to act as an effective cell-penetrating lipopeptide, with additional aggregation propensity conferred by the lipid chain. A combination of cryo-TEM and small-angle X-ray scattering (SAXS) is used to show that the lipopeptide forms micelles, but mixtures with DNA lead to formation of fractal cluster-like co-assemblies due to intercalation of the DNA and peptide. Spectroscopic studies using fluorescence and circular dichroism (along with fiber X-ray diffraction) show that the peptide interacts with DNA and inserts into the groove. Confocal microscopy along with flow cytometry confirms delivery of DNA into both HeLa and mouse embryonic stem cells (mESCs) in pluripotent state, and the system shows excellent cytocompatibility as confirmed by MTT assays. Our data indicate that the lipopeptide may outperform the DNA transfection agent lipofectamine in DNA delivery into these stem cells and it enables DNA delivery into the cytoplasm and nucleus.
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Mar 2026
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I24-Microfocus Macromolecular Crystallography
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Open Access
Abstract: Serial synchrotron crystallography (SSX) enables structure determination from microcrystals under near-physiological, room-temperature conditions but is limited in part due to the inevitable onset of radiation damage. The ability to reduce the absorbed dose while retaining, or even improving, data quality is an attractive means of mitigating this limitation. Advances in detector technology have made the use of high-energy X-rays a routine approach in MX, improving diffraction efficiency and enhancing overall data quality. Here, we systematically evaluate low-dose SSX data collected at five different X-ray energies from 12.4 to 25 keV using a CdTe Eiger2 detector while maintaining a constant dose. Higher photon energies increased the mean diffracted intensity and signal-to-noise ratio per unit dose, and facilitated higher-resolution structure determination, even with limited crystal numbers. These findings highlight the advantages of high-energy X-rays and provide practical guidance for optimizing SSX experiments in probing protein dynamics.
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Mar 2026
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Open Access
Abstract: Nucleophosmin (NPM1) is a nucleolar protein commonly mutated in ~30% of newly diagnosed acute myeloid leukemia (AML) cases. These mutations occur in the terminal exon of the NPM1 gene, affecting the C-terminal DNA-binding domain of the protein and causing its delocalization to the cytoplasm—a hallmark of NPM1-mutated AML. NPM1 shuttling to the nucleoplasm is tightly regulated by posttranslational modifications, such as phosphorylation of Ser254, Ser260, and Tyr271 of the DNA-binding domain. However, the structural mechanisms underlying this process remain unclear. In this work, we show that Ser-to-Asp (S254D–S260D) and Tyr-to-pCMF (para-carboxymethyl phenylalanine) (Y271pCMF) phosphomimetic mutations induce significant structural and dynamical rearrangements, as well as drastic modifications in electrostatic surface potential. These changes compromise recognition of a G-quadruplex sequence from the c-MYC promoter by reducing DNA-binding affinity, reshape histone capturing dynamics, and fade charge segregation in the histone-binding domain. Combination of such substitutions in a triple phosphomimetic variant (S254D–S260D–Y271pCMF) further destabilizes the domain’s structure and triggers protein aggregation. Altogether, these findings suggest that phosphorylation of Ser254, Ser260, and Tyr271 of the C-end DNA-binding domain weakens both DNA affinity and charge block-driven liquid–liquid phase separation, offering a molecular explanation for the delocalization of NPM1 outside of the nucleolus.
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Mar 2026
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I22-Small angle scattering & Diffraction
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Tayyaba
Rabnawaz
,
Nathanael
Leung
,
Leonard C.
Nielsen
,
Robert A.
Harper
,
Richard M.
Shelton
,
Gabriel
Landini
,
Tim
Snow
,
Andy
Smith
,
Nick
Terrill
,
Marianne
Liebi
,
Tan
Sui
Diamond Proposal Number(s):
[20285]
Abstract: Dental caries, one of the most prevalent non-communicable diseases worldwide, is characterised by the progressive deterioration of the structure and mechanical properties of dental hard tissues. In human teeth, dentine is the most abundant mineralised tissue, forming the primary support material. To assess changes in the mechanical properties of dentine caused by dental caries and acid erosion, it is crucial to understand the relationship between organic and inorganic dentine components and their organisation into a 3D anisotropic structure at the nanoscale. Over the past 20 years, alterations in dentine structure caused by caries and artificial demineralisation have been reported using conventional microscopy techniques. However, due to the limited spatial resolution of these techniques, the 3D structural organisation including orientation and degree of alignment of mineralised collagen fibrils at the nanoscale, has not been fully explored. This study investigated alterations in the 3D structure of normal, carious and artificially demineralised dentine using SAXS tensor tomography (SASTT). This technique enabled the observation of differences in the local orientation of organic and inorganic components, as well as variations in local scattering intensity, resulting from natural caries and artificial demineralisation. In comparison to normal dentine, caries caused minor orientational differences of both components but had a major impact on the local X-ray scattering intensity. After artificial demineralisation of the dentine, most of the mineral was lost in the outer layers, resulting in a greater reduction in scattering intensity than that caused by caries.
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Mar 2026
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Open Access
Abstract: Serial crystallography relies on the reproducible production of high-density suspensions of microcrystals, yet sample optimization remains a resource-intensive bottleneck. While phase diagrams provide a theoretical framework for controlling crystal size and number, experimental mapping is traditionally hindered by relatively high sample consumption. We present an automated microbatch-under-oil crystallization approach that rapidly maps phase boundaries using only 15–60 µl (∼0.15–3.8 mg) of protein. While this workflow is ideally suited for refining existing hits, it serves as a standalone platform for characterizing the crystallization landscape of new protein targets. The power of this approach lies in the integration of three distinct strategies that exploit the stable chemical environment of microbatch-under-oil. Firstly, we utilize an ingenious diagonal sampling strategy that traverses the phase boundary parallel to the solubility curve by systematically varying protein-to-precipitant ratios, identifying primary nucleation zones with far greater efficiency than traditional orthogonal grids. Secondly, we employ a linked variation of multiple precipitants to reveal morphology-specific regions, such as the rod versus plate transitions crucial for time-resolved experiments. Finally, we incorporate automated seed-stock titration to precisely define the metastable zone, enabling the predictive rescue of nucleation-limited systems. The synergy of these three strategies enables the systematic decoupling of nucleation from growth, providing a rational route to optimize microcrystal density, size and lattice order. Crucially, by eliminating the evaporation-related variables inherent in vapor diffusion, this method ensures that the chemical coordinates identified during screening remain constant during scale-up to larger volumes. This workflow transforms empirical serial crystallography sample preparation into a rational, reproducible and highly efficient process applicable to both the optimization of known conditions and the de novo development of microcrystal suspensions, tailored to the rigorous demands of modern serial diffraction experiments.
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Mar 2026
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I04-Macromolecular Crystallography
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Diamond Proposal Number(s):
[35120]
Open Access
Abstract: N-myc is a transcription factor, a powerful driver of cellular growth and an important oncoprotein. N-myc interacts with many factors, including the RNA Polymerase III assembly factor, TFIIIC, a six-subunit complex that is essential for the transcription of small, structured RNA. TFIIIC and N-myc mutually restrict each other’s chromatin association, and their complex contributes to quality control in mRNA transcription. We previously demonstrated that the intrinsically disordered transactivation domain of N-myc interacts directly with a sub-complex of TFIIIC, τA. Structural studies by others show that DNA binding of τA is largely mediated by TFIIIC3, leaving open the role of the DNA-binding domain of TFIIIC5. Here, we demonstrate that this domain is a binding site for two regions in the transactivation domain of N-myc, through an integrated approach combining NMR spectroscopy, hydrogen–deuterium exchange mass spectrometry, and interaction assays (pull-downs, ITC, fluorescence polarization, and co-immunoprecipitation). AlphaFold modelling predicts with high-confidence a binding mode for the higher affinity N-myc motif that overlaps with the predicted intramolecular binding site of the C-terminal acidic plug of TFIIIC5, removal of which enhances the binding of N-myc. This model elucidates how the N-myc:TFIIIC5 interaction competes with DNA and other interactions, providing a basis for their mutual regulation.
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Mar 2026
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I14-Hard X-ray Nanoprobe
I18-Microfocus Spectroscopy
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Diamond Proposal Number(s):
[39618, 39938, 302085, 31588, 5116, 36811]
Open Access
Abstract: Correlative microscopy linking synchrotron X-ray fluorescence (SXRF) with optical imaging is valuable for contextualizing chemical element distributions in biology. The spatial correlation necessary to achieve this presents fundamental challenges and can be a significant constraint on accuracy and data interpretation. We present a technical solution based on a finder grid concept, optimized for SXRF correlative studies of metals in biological tissues, with scope for wider adaptation and application. A hierarchically patterned fiducial system was directly etched onto spectroscopically clean quartz substrates via femtosecond laser ablation. This design enables improved correlation among SXRF, optical imaging, and histological staining over a greater range of length scales than conventional registration methods such as the use of tissue architecture from serial sections and the use of electron-microscopy-resolution finder grids and applied fiduciary markers that can introduce XRF-signal-dominating levels of elements such as copper, nickel, gold, and titanium. We present two quartz finder grid formats: a microgrid and a nanogrid design. We demonstrate their utility for rapid ROI relocalization and same-section correlative workflows using human brain tissue. The etched quartz finder grid approach facilitates rapid and reproducible ROI relocalization and alignment across instruments, particularly where integral fiducial markers are sparse or ambiguous.
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Mar 2026
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I03-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
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Mariska
De Munnik
,
Amelia
Brasnett
,
Tiankun
Zhou
,
William
Myers
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Yicheng
Wang
,
Kuntal
Chatterjee
,
Anthony
Tumber
,
Stephen A.
Marshall
,
Philipp S.
Simon
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Pierre
Aller
,
Anastasiia
Shilova
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Danny
Axford
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Hiroki
Makita
,
Daniel W.
Paley
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Vandana
Tiwari
,
Alexander T.
Stead
,
Sebastian
Dehe
,
Humberto
Sanchez
,
Daniel J.
Rosenberg
,
Roberto
Alonso-Mori
,
Asmit
Bhowmick
,
Junko
Yano
,
Vittal K.
Yachandra
,
Jaehyun
Park
,
Sehan
Park
,
Allen M.
Orville
,
Lennart
Brewitz
,
Jan F.
Kern
,
Christopher J.
Schofield
,
Patrick
Rabe
Diamond Proposal Number(s):
[32727, 31353]
Open Access
Abstract: Protein-hydroxylation catalysed by Fe(II) and 2-oxoglutarate (2OG) dependent oxygenases is an important regulatory mechanism in human biology. Such oxygenases typically coordinate their Fe(II) cofactor via a conserved triad of an aspartate- or glutamate- and two histidine-residues. By contrast, aspartate/asparagine β-hydroxylase (AspH), which catalyses asparagine/aspartate-residue oxidation in epidermal growth factor-like domains (EGFDs), has only two histidine-residues (H679, H725), with a water occupying the site normally occupied by an aspartate- or glutamate-residue. We describe mechanistic studies with catalytically active AspH crystals. Turnover studies with single crystals under cryogenic conditions give (3 R)-hydroxylated EGFDs with the product alcohol coordinating Fe(II) trans to H725. Time-resolved serial crystallography of microcrystals using an acoustic droplet ejection system, coupled to X-ray emission analyses, demonstrate turnover within 1.5 s, giving a product complex in which Fe(II) is regenerated. Solution and crystallographic studies with the O2 surrogate nitric oxide imply O2 binds to Fe(II) trans to H725. The additional Fe-chelating water is maintained throughout AspH catalysis and is not directly involved in substrate hydroxylation, because O2 is the sole oxygen source in alcohol products, as shown by 18O labelling studies. The results reveal how AspH accommodates both aspartate- and asparagine-substrates and will assist in efforts targeting AspH for cancer treatment.
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Feb 2026
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