Krios II-Titan Krios II at Diamond
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Zak
Mciver
,
Didi
He
,
Jennifer
Ross
,
Marta
Cozzaglio
,
Cecilia
Piergentili
,
Aritha
Dornau
,
Natasha
Sumpner
,
Finn
Brady
,
Kathleen
Bialik
,
Thomas
Mccorvie
,
Claudia
Sissi
,
Arnaud
Basle
,
David J.
Clarke
,
Jon
Marles-Wright
Diamond Proposal Number(s):
[31827]
Open Access
Abstract: Encapsulins are self-assembling protein nanocompartments found in bacteria and archaea that encapsulate cargo enzymes to protect the cell from their toxic reaction products or intermediates. Developments in cryo-electron microscopy (cryo-EM) data processing strategies have enabled encapsulins and their cargo proteins to be investigated together in greater detail. In this study, we present the single particle cryo-EM structure of the Rhodospirillum rubrum encapsulin in both the presence and absence of its partner encapsulated ferritin (EncFtn). Single particle icosahedral reconstructions of empty and loaded encapsulins revealed a higher degree of conformational flexibility at the five-fold pore in the cargo loaded encapsulin. We applied a new non-point group averaging workflow to analyze the encapsulated ferritins within the encapsulin nanocompartment, to produce the first fully refined in situ atomic model of the EncFtn at 2.8 Å resolution. Masked 2D classification and particle subtraction demonstrate that cargo loading is heterogeneous in this recombinant complex, with the encapsulin able to house up to five of the decameric EncFtn complexes. Our data provides new insights into the dynamics and cargo arrangement in encapsulins and demonstrates an adaptable workflow for high resolution reconstruction of encapsulin cargoes.
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Sep 2026
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Krios III-Titan Krios III at Diamond
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Jesper S.
Hansen
,
Ashley C. W.
Pike
,
Gamma
Chi
,
Gernot
Wolf
,
Jeppe
Tranberg-Jensen
,
Hannah
Lichtmannegger
,
David
Speedman
,
Alvaro
Ingles-Prieto
,
Fabian
Goericke
,
Helena
Batoulis
,
Hartmut
Beck
,
Rajini
Rao
,
Tooraj
Mirshahi
,
David B.
Sauer
,
Giulio
Superti-Furga
,
Kilian V. M.
Huber
Diamond Proposal Number(s):
[28713]
Open Access
Abstract: Endosomal NHE6 (SLC9A6) and NHE9 (SLC9A9) transporters are essential for maintaining pH homeostasis within endosomes and their dysfunction has been linked to neurological and neurodegenerative disorders. NHE6 and NHE9 are widely considered to function as electroneutral exchangers that couple the export of protons to the import of sodium or potassium ions across cellular membranes, thereby forming the basis of proton leak pathways for internal pH balancing and fine-tuning. Among the 13 identified SLC9 family members, only NHE6 and NHE9 are targeted to endosomes. Despite their biological importance and therapeutic potential, the structural basis for their activity and regulation remains elusive. Here, we present the cryo-EM structures of human NHE9 and two splice variants of NHE6 that differ by alternative inclusion of the β-hairpin motif-containing loop domain located between transmembrane helices 2 and 3, showcasing structural diversity within the organellar NHE subfamily. By mapping the sodium-binding site, our results provide mechanistic insights into ion transport, and for NHE6 we provide evidence for a conserved PIP2-mediated regulatory mechanism. These findings provide a framework for understanding endosomal NHE function with implications for disorders such as Alzheimer’s disease and glioblastoma.
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Sep 2026
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Krios I-Titan Krios I at Diamond
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Ana Raquel
Pereira
,
Silvia
Di Francescantonio
,
Ana
Da Rosa Soares
,
Tianyang
Liu
,
Filomena A.
Carvalho
,
Josie Liane
Ferreira
,
Graciano
Leal
,
Inês
Faleiro
,
Naoko
Kogata
,
Beatrice
Labella
,
Teresinha
Evangelista
,
Nuno C.
Santos
,
Michael
Way
,
Carolyn A.
Moores
,
Edgar R.
Gomes
Diamond Proposal Number(s):
[20287]
Open Access
Abstract: A network of plasma membrane invaginations called t-tubules plays an essential role in controlling calcium release from the endoplasmic reticulum at the triads during muscle contraction. Although the importance of t-tubules for muscle physiology is well established, and abnormalities are found in muscle disorders, the mechanisms that mediate t-tubule growth are unknown. We show that the actomyosin cortex beneath the plasma membrane, regulated by Arp2/3 complexes containing Arpc5, acts as a gatekeeper for the membrane availability during t-tubule growth. Enlarged t-tubules are formed upon disruption of Arpc5, impairing the synchronization between plasma membrane depolarization and calcium release. Knockout of Arpc5 in mouse skeletal muscle results in impaired locomotion and posture. Furthermore, we show that human triadopathy patients and Arpc5 knockout mice accumulate enlarged t-tubules. We propose that cortex-dependent membrane availability affects muscle function, offering a potential pathophysiological mechanism for muscle disorders.
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Sep 2026
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Krios I-Titan Krios I at Diamond
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Stephanie A.
Nestorow
,
Wan-Na
Chen
,
Daniel
Bertrand
,
Ayla A.
Wahid
,
Caroline E.
Wyatt
,
Martin
Mortensen
,
Thomas
Clairfeuille
,
Michael
Reutlinger
,
Gregoire
Friz
,
Els
Pardon
,
Jan
Steyaert
,
Graham
Ladds
,
Giuseppe
Cecere
,
Trevor G.
Smart
,
Maria-Clemencia
Hernandez
,
Lisa
Joedicke
,
Paul S.
Miller
Diamond Proposal Number(s):
[37678]
Open Access
Abstract: γ-aminobutyric acid Type-A (GABAA) αβδ receptors regulate neuronal excitability and contribute to sleep, mood and motor coordination. However, the molecular arrangements of these receptors and the basis of GABA activation and δ-selective drug modulation remain unclear. We solve cryo-EM structures of α4β3δ receptors in an α-β-α-β-δ arrangement that contains two GABA binding pockets. GABA binding supports a classical β-subunit tilt and an outward configuration of the β-subunit M2-M3 loops. However, the δ subunit M2-M3 loop is orientated inward and the 9’ activation gate in the pore is closed, consistent with the low efficacy for these receptors. Addition of a δ-selective positive allosteric modulator (PAM), DS2-Me, reveals binding to an α-δ pocket that causes the 9’ activation gate to open. In this work we provide key insights into the stoichiometry, arrangement and molecular modes of GABA activation and δ-selective modulation of these critical regulators of neuronal excitability.
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Aug 2026
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I06-Nanoscience (XPEEM)
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Diamond Proposal Number(s):
[38242]
Open Access
Abstract: We report the evolution of the antiferromagnetic domain structure of epitaxial La0.45Sr0.55MnO3 (LSMO) ultrathin films with thickness in the range from 5–50 unit cells (uc), using x-ray photoemission electron microscopy (XPEEM). While the 5 uc thick LSMO shows no magnetic contrast down to ∼80K, thicker films display a multidomain antiferromagnetic configuration with a nonmonotonic variation in the characteristic domain size from 0.3 µm at 10 uc, to 3–5 µm at 15–16 uc and 1 µm for 50 uc. Post-growth annealing is found not to impact strongly the magnetic domain state. In contrast, for a 15 uc film grown on a substrate characterized by large atomic steps (∼1µm), we observe much larger antiferromagnetic domains and the presence of net magnetic moment in the form of stripes with alternating contrast, assigned to the signal from the top uncompensated spins of the A-type antiferromagnetic state of LSMO. From the combined antiferromagnetic domain structure and the net magnetic moment contrast, we determine the exact orientation of the Néel vector, including at domain walls. We describe the antiferromagnetic domain size distribution in terms of interface and bulk contributions to the density of defects that pin the antiferromagnetic domain walls and which determine the equilibrium domain configuration. Our results demonstrate the impact of thickness and defects on the antiferromagnetic domain size and constitute a stepping stone in controlling the antiferromagnetic domain state required for oxide antiferromagnetic device applications.
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Aug 2026
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Krios I-Titan Krios I at Diamond
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Miriam
Weckener
,
Audrey
Le Bas
,
Philip N.
Ward
,
Bradley R.
Clarke
,
Peter J.
Harrison
,
Stephen A.
Mcmahon
,
Huanting
Liu
,
Alice
Eddershaw
,
Andrew M.
Giltrap
,
Els
Pardon
,
Abirami
Lakshminarayanan
,
Jan
Steyaert
,
Benjamin G.
Davis
,
Chris
Whitfield
,
James H.
Naismith
Diamond Proposal Number(s):
[29493, 27436]
Open Access
Abstract: Host–pathogen interactions frequently depend on key components of the bacterial cell surface, such as capsules and lipopolysaccharides in Gram-negative bacteria. The first step in the synthesis of lipid-linked polysaccharides is the substitution of a uridine diphosphate (UDP)-sugar by a lipid monophosphate catalysed by a phosphoglycosyl transferase (PGT). We report the 3.0 Å cryo-electron microscopy apo-structure of the PGT enzyme WbaP from Escherichia coli, a UDP-galactose:undecaprenolphosphate galactose-1-phosphoryl transferase. The structure is a dimer with each monomer formed of four N-terminal transmembrane helices, a small α/β domain with a distinctive β-hairpin that inserts into the other monomer, and a catalytic domain, which sits perpendicular to the transmembrane domain. A complex of WbaP with the UDP-galactose substrate shows binding of the UDP moiety by R319 and R377. Mutations of R319 and R377, along with K331 and R401, highlighted the essential nature of these residues for the catalytic activity of the protein, as confirmed by an in vivo functional assay. Our results provide new insights into the PGT family of enzymes.
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Aug 2026
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E01-JEM ARM 200CF
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Jianan
He
,
Adrian Chun Minh
Loy
,
Jining
Guo
,
Ali
Zavabeti
,
Lei
Dong
,
Jia Ming
Goh
,
Chao
Wu
,
Dingqi
Wang
,
Qining
Fan
,
Caiden J.
Parker
,
Martin J.
Taylor
,
Jitraporn
Vongsvivut
,
Longbing
Qu
,
Joshua D.
Butson
,
Gang Kevin
Li
,
Qinfen
Gu
Diamond Proposal Number(s):
[42384]
Abstract: The hydrogen evolution reaction (HER) exhibits pH- and electrolyte-dependent pathways, imposing intrinsic challenges on the development of catalysts that operate efficiently across wide pH conditions and in seawater electrolysis. Here, we report a dual-single-atom catalyst with proximate cooperative Pt and Ni sites on a MXene (Ti3C2Tx) platform that enables synergistic optimization of HER elementary steps. A one-step molten salt-assisted strategy, free of F-based chemicals, allows the construction of high-density, well-dispersed Pt and Ni single atoms on MXene with well-defined coordination environments. Atomic-resolution microscopy and x-ray absorption spectroscopy confirm the stabilization of isolated Pt and Ni sites, while in situ synchrotron-based FTIR and DFT calculations reveal that proximate Ni sites modulate the electronic structure of Pt, weakening hydrogen adsorption and promoting water dissociation. As a result, the PtSAsNiSAs/Ti3C2Tx delivers low overpotentials of 22.6 and 59.1 mV at 100 mA cm−2 in acidic and alkaline electrolytes, respectively, and maintains high activity in neutral electrolyte (282 mV) and alkaline seawater (73.2 mV) with stability up to 100 h, outperforming commercial 20% Pt/C. These findings demonstrate that leveraging the intrinsic surface chemistry of MXenes enables cooperative dual-single-atom architectures with synergistically optimized HER pathways, driven by inter-site electronic coupling across diverse pH conditions.
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Aug 2026
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Krios I-Titan Krios I at Diamond
Krios IV-Titan Krios IV at Diamond
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Yasunori
Noguchi
,
Almutasem
Saleh
,
Sarah
Schneider
,
Marina E.
Ivanova
,
Zhuo Angel
Chen
,
Lepakshi
Ranjha
,
Ricardo
Aramayo
,
Silvia
Tognetti
,
Sarah V.
Faull
,
Juri
Rappsilber
,
Christian
Speck
Diamond Proposal Number(s):
[25127, 18659]
Open Access
Abstract: Regulated helicase activation by DDK kinase is central for genome stability. However, how DDK phosphorylation primes the MCM2-7 double hexamer (DH) for Sld3-Sld7 binding and Cdc45 loading remained unclear. We define this mechanism through cryo-EM structures of MCM2-7 DH-Sld3-Sld7 (MS) and MCM2-7 DH-Sld3-Sld7-Cdc45 (MSC). We reveal that the autoinhibitory Mcm4 tail engages not only Mcm4 but also Mcm6. Upon DDK-dependent phosphorylation, both of these sites become accessible. In the context of the MS structure, we identify that two short Sld3 motifs that contact Mcm4 and Mcm6 read out the DH phosphorylation state, while the Sld3 Treslin domain (STD) binds to Mcm2. In the MSC structure, Cdc45 dislodges the Sld3 STD from Mcm2, allowing Sld3 to position Cdc45 at the Mcm2/Mcm5 interface. Mutagenesis of the Sld3 STD-Cdc45 interface disrupts Cdc45 loading, validating this interaction. Together, our data reveal a phosphorylation-encoded mechanism coupling DDK-activated Mcm4/Mcm6 surfaces to distal Cdc45 placement, explaining how firing factors choreograph the DH-to-CMG transition.
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Aug 2026
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Krios I-Titan Krios I at Diamond
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Diamond Proposal Number(s):
[42543]
Open Access
Abstract: During bacterial ribosome recycling, 70S ribosomes are split into subunits by ribosome recycling factor (RRF) and elongation factor G (EF-G). The antibiotic fusidic acid (FA) inhibits elongation and ribosome recycling by locking EF-G to the ribosome. Yet, no functional ribosome recycling FA complex has been successfully captured. Here, we used single-particle cryo-electron microscopy to resolve multiple FA-stalled intermediates of Staphylococcus aureus ribosomes, including a 70S intermediate with RRF and EF-G in a previously unobserved conformation. Our structures reveal how RRF and EF–G jointly disrupt inter-subunit bridges, promote back–rotation of the small subunit, and move the transfer RNA toward the E site to facilitate ribosome splitting. We further show that FA predominantly inhibits recycling by trapping EF-G on the post-termination complex in the absence of RRF, preventing formation of the active RRF•EF-G complex. These insights advance understanding of the molecular mechanism of bacterial ribosome recycling and the mode of action of FA as an antibiotic.
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Aug 2026
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B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS
E01-JEM ARM 200CF
I20-Scanning-X-ray spectroscopy (XAS/XES)
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Yanqi
Dai
,
Zhangyi
Yao
,
Hao-Xin
Liu
,
Lu
Chen
,
Xinlian
Su
,
Matteo
D'Andria
,
Matthijs A.
Van Spronsen
,
Nitya
Ramanan
,
Shusaku
Hayama
,
Andreas T.
Güntner
,
Chun-Jiang
Jia
,
Feng Ryan
Wang
Diamond Proposal Number(s):
[33314, 33267, 38085, 37962]
Open Access
Abstract: Efficient nitrous oxide (N2O) decomposition relies on coupled redox cycles, yet it remains unclear how deeply into the catalyst these redox changes extend under working conditions and what oxygen-exchange depth is required to sustain turnover. Here we combine inverse CeO2/CuO architectures with depth-resolved X-ray spectroscopy to identify the active redox motif and the operative oxygen-exchange zone. 20 wt % CuO/CeO2 and inverse CeO2/90 wt % CuO catalysts were prepared by flame spray pyrolysis (FSP) and coprecipitation (CP), generating distinct Cu–Ce interfacial structures for N2O conversion. The inverse 90FSP is more active than the conventional 20FSP and coprecipitated 90CP catalysts under the conditions studied. Bulk-sensitive Cu K-edge HERFD-XANES reveals only minor changes in Cu oxidation state under reaction conditions, showing that bulk-averaged Cu redox is not the descriptor for the activity trend. In contrast, surface-sensitive Cu L-edge spectra uncover pronounced, reversible Cu2+/Cu+ cycling that is strongly localized in the surface and subsurface regions and, critically, a sustained surface-subsurface Cu2+/Cu+ redox gradient that is unique to the most active 90FSP catalyst. Mechanistically, this pronounced surface-subsurface Cu2+/Cu+ ratio contrast indicates that N2O-driven surface Cu redox turnover is sufficiently fast that it cannot be fully equilibrated by lattice oxygen exchange (O2– equilibration) with the subsurface. These results identify interface density and temperature-dependent redox depth as a design and diagnostic principle for metal–oxide redox catalysis.
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Aug 2026
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