I09-Surface and Interface Structural Analysis
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Paul
Ryan
,
Panukorn
Sombut
,
Ali
Rafsanjani-Abbasi
,
Chunlei
Wang
,
Fulden
Eratam
,
Francesco
Goto
,
Cesare
Franchini
,
Ulrike
Diebold
,
Matthias
Meier
,
David A.
Duncan
,
Gareth S.
Parkinson
Diamond Proposal Number(s):
[31726]
Open Access
Abstract: Water–solid interfaces pervade the natural environment and modern technology. On some surfaces, water–water interactions induce the formation of partially dissociated interfacial layers; understanding why is important to model processes in catalysis or mineralogy. The complexity of the partially dissociated structures often makes it difficult to probe them quantitatively. Here, we utilize normal incidence X-ray standing waves (NIXSW) to study the structure of partially dissociated water dimers (H2O–OH) at the α-Fe2O3(012) surface (also called the (11̅02) or “R-cut” surface): a system simple enough to be tractable yet complex enough to capture the essential physics. We find the H2O and terminal OH groups to be the same height above the surface within experimental error (1.45 ± 0.04 and 1.47 ± 0.02 Å, respectively), in line with DFT-based calculations that predict comparable Fe–O bond lengths for both water and OH species. This result is understood in the context of cooperative binding, where the formation of the H-bond between adsorbed H2O and OH induces the H2O to bind more strongly and the OH to bind more weakly compared to when these species are isolated on the surface. The surface OH formed by the liberated proton is found to be in plane with a bulk truncated (012) surface (−0.01 ± 0.02 Å). DFT calculations based on various functionals correctly model the cooperative effect but overestimate the water–surface interaction.
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Sep 2024
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I13-1-Coherence
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Diamond Proposal Number(s):
[25097, 28495, 30308]
Abstract: Understanding the impact of strain (structural deformation) is crucial to the success of halide perovskite materials used in optoelectronic devices such as solar cells, X-ray detectors, and LEDs. While halide perovskites demonstrate the potential for enhanced efficiency in these devices, research is ongoing to investigate strain and defects that still hinder device performance and stability.
In experiments to understand the structural changes that can occur during device operation, scientists used Synchrotron-based Bragg Coherent Diffraction Imaging (BCDI) - an X-ray-based imaging technique - to map nanoscale strain in halide perovskite microcrystals (MAPbBr3 [MA = CH3NH3]), including strain around defects. Published in Advanced Materials, the experiments were part of a recent study from Diamond’s I13-1 beamline (Figure 1), which reveals the dynamic migration of nanoscale extended defects in halide perovskites under continuous light illumination. These insights demonstrate the highly dynamic nature of the structure of halide perovskite materials and how they evolve under operational conditions, highlighting the close links between nanoscale structure, dislocations, and device performance and stability.
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Sep 2024
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I22-Small angle scattering & Diffraction
labSAXS-Offline SAXS and Sample Environment Development
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Diamond Proposal Number(s):
[26258, 19127]
Abstract: Lipid nanoparticles have important applications as biomedical delivery platforms and broader engineering biology applications in artificial cell technologies. These emerging technologies often require changes in the shape and topology of biological or biomimetic membranes. Here we show that topologically-active lyotropic liquid crystal nanoparticles (LCNPs) can trigger such transformations in the membranes of giant unilamellar vesicles (GUVs). Monoolein (MO) LCNPs, cubosomes with an internal nanostructure of space group Im3m incorporate into 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) GUVs creating excess membrane area with stored curvature stress. Using time-resolved fluorescence confocal and lattice light sheet microscopy, we observe and characterise various life-like dynamic events in these GUVs, including growth, division, tubulation, membrane budding and fusion. Our results shed new light on the interactions of LCNPs with bilayer lipid membranes, providing insights relevant to how these nanoparticles might interact with cellular membranes during drug delivery and highlighting their potential as minimal triggers of topological transitions in artificial cells.
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Sep 2024
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B21-High Throughput SAXS
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Diamond Proposal Number(s):
[37105]
Abstract: Star-shaped block copolymers (SBCs) have sparked interest as efficient cargo carriers due to their high loading capacity, decreased burst effects through sustained release, and maintained stability in dilute aqueous solution. Despite these advantages, the practical usage of SBCs is hindered by their challenging synthesis processes that often utilize metal-based catalysts at high temperatures. Herein we report the tailored synthesis of 3-, 4-, and 6-arm polycaprolactone-b-poly(ethylene glycol), PCL-b-PEG, SBCs using diphenyl phosphate as a friendlier, more sustainable non-metallic catalyst. Nuclear magnetic resonance (NMR) analysis confirms the molecular architecture of SBCs and gel permeation chromatography (GPC) is used to elucidate trends in molar mass when the number of arms within the SBCs is tuned, while dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) studies provide insights into aggregation behavior. Critical aggregation concentration (CAC) values, as measured by fluorescence spectroscopy, demonstrated that the 4-arm and 6-arm SBCs have greater stability than the 3-arm SBC. Biocompatibility assessment indicated minimal cytotoxicity of the nanoaggregates, even at high concentration, making these PCL-b-PEG SBCs potentially safe and sustainable vehicles for biomedical release applications.
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Sep 2024
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Xiao
Wang
,
Jie
Zhang
,
Zhao
Pan
,
Dabiao
Lu
,
Maocai
Pi
,
Xubin
Ye
,
Cheng
Dong
,
Jie
Chen
,
Kai
Chen
,
Florin
Radu
,
Sonia
Francoual
,
Stefano
Agrestini
,
Zhiwei
Hu
,
Chun-Fu
Chang
,
Arata
Tanaka
,
Kazunari
Yamaura
,
Yao
Shen
,
Youwen
Long
Abstract: By means of X-ray absorption spectroscopic studies, both experimentally and theoretically, we investigated the magnetic properties of the transition-metal-only double perovskite oxide Mn2CoReO6, which experiences an antiferromagnetic transition at TN = 93 K, whereas it holds a considerable net moment at low temperature. Internal exchange fields against the applied magnetic field for all the transition metal ions were identified, providing a microscopic insight into the intrasite antiferromagnetic couplings. Nevertheless, parallelly oriented canted spins of the Mn, Co, and Re cations were observed. In particularly, the Mn and Co cations hold considerable canting moments, which can be ascribed to the competition between the ferromagnetic intersite and antiferromagnetic intrasite magnetic interactions. Moreover, a spin-valve-type magnetoresistance was observed below the TN. The concurrence of the magnetoresistance effect and the antiferromagnetic semiconductive nature make Mn2CoReO6 a promising candidate for high-speed and energy-saving spintronics applications.
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Sep 2024
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[28766, 36069]
Open Access
Abstract: Developing new methods to control the size and shape of the helical structures adopted by foldamers is highly important as the secondary structure displayed by these supramolecular scaffolds often dictates their activity and function. Herein, we report on a systematic study demonstrating that the helical pitch of ortho-azobenzene/2,6-pyridyldicarboamide foldamers can be readily controlled through the nature of the terminal functionality. Remarkably, simply through varying the end group of the foldamer, and without modifying any other structural features of the scaffold, the helical pitch can be over doubled in magnitude (from 3.4 Å to 7.3 Å). Additionally, crystallographic analysis of a library ten foldamers has identified general trends in the influence of a range of terminal functionalities, including carboxylbenzyl (Cbz), diphenylcarbamyl (N(Ph)2), ferrocene (Fc) and tert-butyloxycarbonyl (Boc), in controlling the folding behaviour of these supramolecular scaffolds. These studies could prove useful in the future development of functional foldamers which adopt specific sizes and shapes.
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Sep 2024
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B18-Core EXAFS
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Abstract: The MoS2 nanosheets are acquired via a facile hydrothermal strategy, and the M/MoS2 (M = Pt, Rh, Pd, Ru) samples are gained by impregnation. By comparing the catalytic behaviors of these catalysts for p-nitroacetophenone selective hydrogenation, it is found that the catalytic property and selectivity for one −NO2 group hydrogenation of Ru/MoS2 outperform those of other as-prepared catalysts. In addition, the Ru/MoS2 catalysts with various Ru contents (0.37, 0.88, or 2.45 wt %) are used for 3-nitrostyrene selective hydrogenation, and the results show that 0.88 wt % Ru/MoS2 displays the highest catalytic activity (turnover frequency) of TOF = 118.4 h–1 (TOF = 64.2 h–1 for 0.37 wt %Ru/MoS2 and TOF = 61.7 h–1 for 2.45 wt %Ru/MoS2) under the reaction conditions of 100 °C, 3.0 MPa H2, and 1 h. The nanostructure characterization of the as-prepared catalysts (XRD, XPS, TEM, HRTEM, H2-TPD, XAS, AC-STEM, AC-STEM-EDX elemental mapping, and line scanning) demonstrate that Ruδ+ single atoms and Ru clusters are well dispersed on the support. Moreover, 0.88 wt % Ru/MoS2 exhibits extremely high selectivity of one −NO2 group hydrogenation (∼100%) at high conversion for other selected nitroaromatics’ hydrogenation, such as nitrobenzene, 2-chloronitrobenzene, 1,3-dinitrobenzene, 3-nitrostyrene, p-nitroacetophenone, and p-nitrobenzonitrile. This is mainly due to the fact that Ru is present with single atoms and clusters, producing the synergism of Ruδ+ single atoms, Ru clusters, and MoS2 nanosheets. And the synergism mechanism is given below: hydrogen is preferentially adsorbed and activated at Ru clusters (forming activated H* species), the −NO2 group is easily adsorbed and activated at Ruδ+ single atoms (charge interaction between electrons from O in −NO2 and positive charge from Ruδ+ single atoms), and H* transfers to Ruδ+ single atoms by the hydrogen spillover effect of the MoS2 nanosheets, reacting with the −NO2 group, forming desired aromatic amines.
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Sep 2024
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Krios IV-Titan Krios IV at Diamond
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Clarissa N.
Pacyna
,
Madhanagopal
Anandapadamanaban
,
Kevin W.
Loudon
,
Iain M.
Hay
,
Olga
Perisic
,
Ruoyan
Li
,
Matthew
Byrne
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Laura
Allen
,
Kirsty
Roberts
,
Yvette
Hooks
,
Anne Y.
Warren
,
Grant D.
Stewart
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Menna R.
Clatworthy
,
Sarah A.
Teichmann
,
Sam
Behjati
,
Peter J.
Campbell
,
Roger L.
Williams
,
Thomas J.
Mitchell
Diamond Proposal Number(s):
[23268]
Open Access
Abstract: Embryogenesis is a vulnerable time. Mutations in developmental cells can result in the wide dissemination of cells predisposed to disease within mature organs. We characterised the evolutionary history of four synchronous renal tumours from a 14-year-old girl using whole genome sequencing alongside single cell and bulk transcriptomic sequencing. Phylogenetic reconstruction timed the origin of all tumours to a multipotent embryonic cell committed to the right kidney, around 4 weeks post-conception. Biochemical and structural analysis of their shared MTOR mutation, absent from normal tissues, demonstrates enhanced protein flexibility, enabling a FAT domain hinge to dramatically increase activity of mTORC1 and mTORC2. Developmental mutations, not usually detected in traditional genetic screening, have vital clinical importance in guiding prognosis, targeted treatment, and family screening decisions for paediatric tumours.
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Sep 2024
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I24-Microfocus Macromolecular Crystallography
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Johannes
Popow
,
William
Farnaby
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Andreas
Gollner
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Christiane
Kofink
,
Gerhard
Fischer
,
Melanie
Wurm
,
David
Zollman
,
Andre
Wijaya
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Nikolai
Mischerikow
,
Carina
Hasenoehrl
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Polina
Prokofeva
,
Heribert
Arnhof
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Silvia
Arce-Solano
,
Sammy
Bell
,
Georg
Boeck
,
Emelyne
Diers
,
Aileen B.
Frost
,
Jake
Goodwin-Tindall
,
Jale
Karolyi-Oezguer
,
Shakil
Khan
,
Theresa
Klawatsch
,
Manfred
Koegl
,
Roland
Kousek
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Barbara
Kratochvil
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Katrin
Kropatsch
,
Arnel A.
Lauber
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Ross
Mclennan
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Sabine
Olt
,
Daniel
Peter
,
Oliver
Petermann
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Vanessa
Roessler
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Peggy
Stolt-Bergner
,
Patrick
Strack
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Eva
Strauss
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Nicole
Trainor
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Vesna
Vetma
,
Claire
Whitworth
,
Siying
Zhong
,
Jens
Quant
,
Harald
Weinstabl
,
Bernhard
Kuster
,
Peter
Ettmayer
,
Alessio
Ciulli
Diamond Proposal Number(s):
[14980]
Abstract: Mutations in the Kirsten rat sarcoma viral oncogene homolog (KRAS) protein are highly prevalent in cancer. However, small-molecule concepts that address oncogenic KRAS alleles remain elusive beyond replacing glycine at position 12 with cysteine (G12C), which is clinically drugged through covalent inhibitors. Guided by biophysical and structural studies of ternary complexes, we designed a heterobifunctional small molecule that potently degrades 13 out of 17 of the most prevalent oncogenic KRAS alleles. Compared with inhibition, KRAS degradation results in more profound and sustained pathway modulation across a broad range of KRAS mutant cell lines, killing cancer cells while sparing models without genetic KRAS aberrations. Pharmacological degradation of oncogenic KRAS was tolerated and led to tumor regression in vivo. Together, these findings unveil a new path toward addressing KRAS-driven cancers with small-molecule degraders.
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Sep 2024
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Krios III-Titan Krios III at Diamond
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Diamond Proposal Number(s):
[26876]
Abstract: To organize microtubules, cells tightly control the activity of the microtubule nucleator γ-tubulin ring complex (γTuRC). The open ring-shaped γTuRC was proposed to nucleate microtubules by a template mechanism. However, its splayed structure does not match microtubule symmetry, leaving it unclear how γTuRC becomes an efficient nucleator. Here, we identify the mechanism of γTuRC activation by CDK5RAP2 centrosomin motif 1 (CM1). Using cryoelectron microscopy (cryo-EM), we find that activation involves binding of multiple CM1 dimers to five distinct sites around the outside of the γTuRC cone, which crucially depends on regulatory modules formed by MZT2 and the N-terminal extensions of GCP2 subunits. CM1 binding promotes lateral interactions between GCP subunits to facilitate microtubule-like conformations and release of luminal actin that is integral to non-activated γTuRC. We propose a model where generation of γTuRC with an expanded conformational range, rather than perfect symmetry, is sufficient to boost nucleation activity.
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Sep 2024
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