I18-Microfocus Spectroscopy
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Anouk M.
Borst
,
Martin P.
Smith
,
Adrian
Finch
,
Guillaume
Estrade
,
Cristina
Villanova-de-benavent
,
Peter
Nason
,
Eva
Marquis
,
Nicola J.
Horsburgh
,
Kathryn M.
Goodenough
,
Cheng
Xu
,
Jindřich
Kynický
,
Kalotina
Geraki
Diamond Proposal Number(s):
[14793, 15903]
Open Access
Abstract: Global resources of heavy Rare Earth Elements (REE) are dominantly sourced from Chinese regolith-hosted ion-adsorption deposits in which the REE are inferred to be weakly adsorbed onto clay minerals. Similar deposits elsewhere might provide alternative supply for these high-tech metals, but the adsorption mechanisms remain unclear and the adsorbed state of REE to clays has never been demonstrated in situ. This study compares the mineralogy and speciation of REE in economic weathering profiles from China to prospective regoliths developed on peralkaline rocks from Madagascar. We use synchrotron X-ray absorption spectroscopy to study the distribution and local bonding environment of Y and Nd, as proxies for heavy and light REE, in the deposits. Our results show that REE are truly adsorbed as easily leachable 8- to 9-coordinated outer-sphere hydrated complexes, dominantly onto kaolinite. Hence, at the atomic level, the Malagasy clays are genuine mineralogical analogues to those currently exploited in China.
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Dec 2020
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I03-Macromolecular Crystallography
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Open Access
Abstract: Enzyme regulation is vital for metabolic adaptability in living systems. Fine control of enzyme activity is often delivered through post-translational mechanisms, such as allostery or allokairy. β-phosphoglucomutase (βPGM) from Lactococcus lactis is a phosphoryl transfer enzyme required for complete catabolism of trehalose and maltose, through the isomerisation of β-glucose 1-phosphate to glucose 6-phosphate via β-glucose 1,6-bisphosphate. Surprisingly for a gatekeeper of glycolysis, no fine control mechanism of βPGM has yet been reported. Herein, we describe allomorphy, a post-translational control mechanism of enzyme activity. In βPGM, isomerisation of the K145-P146 peptide bond results in the population of two conformers that have different activities owing to repositioning of the K145 sidechain. In vivo phosphorylating agents, such as fructose 1,6-bisphosphate, generate phosphorylated forms of both conformers, leading to a lag phase in activity until the more active phosphorylated conformer dominates. In contrast, the reaction intermediate β-glucose 1,6-bisphosphate, whose concentration depends on the β-glucose 1-phosphate concentration, couples the conformational switch and the phosphorylation step, resulting in the rapid generation of the more active phosphorylated conformer. In enabling different behaviours for different allomorphic activators, allomorphy allows an organism to maximise its responsiveness to environmental changes while minimising the diversion of valuable metabolites.
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Nov 2020
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I06-Nanoscience
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S.
Duttagupta
,
A.
Kurenkov
,
O. A.
Tretiakov
,
G.
Krishnaswamy
,
G.
Sala
,
V.
Krizakova
,
F.
Maccherozzi
,
S. S.
Dhesi
,
P.
Gambardella
,
S.
Fukami
,
H.
Ohno
Diamond Proposal Number(s):
[20413]
Open Access
Abstract: The ability to represent information using an antiferromagnetic material is attractive for future antiferromagnetic spintronic devices. Previous studies have focussed on the utilization of antiferromagnetic materials with biaxial magnetic anisotropy for electrical manipulation. A practical realization of these antiferromagnetic devices is limited by the requirement of material-specific constraints. Here, we demonstrate current-induced switching in a polycrystalline PtMn/Pt metallic heterostructure. A comparison of electrical transport measurements in PtMn with and without the Pt layer, corroborated by x-ray imaging, reveals reversible switching of the thermally-stable antiferromagnetic Néel vector by spin-orbit torques. The presented results demonstrate the potential of polycrystalline metals for antiferromagnetic spintronics.
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Nov 2020
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I15-1-X-ray Pair Distribution Function (XPDF)
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Louis
Longley
,
Courtney
Calahoo
,
René
Limbach
,
Yang
Xia
,
Joshua M.
Tuffnell
,
Adam F.
Sapnik
,
Michael F.
Thorne
,
Dean S.
Keeble
,
David A.
Keen
,
Lothar
Wondraczek
,
Thomas D.
Bennett
Diamond Proposal Number(s):
[20038]
Open Access
Abstract: Metal-organic framework (MOF) glasses have become a subject of interest as a distinct category of melt quenched glass, and have potential applications in areas such as ion transport and sensing. In this paper we show how MOF glasses can be combined with inorganic glasses in order to fabricate a new family of materials composed of both MOF and inorganic glass domains. We use an array of experimental techniques to propose the bonding between inorganic and MOF domains, and show that the composites produced are more mechanically pliant than the inorganic glass itself.
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Nov 2020
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I02-Macromolecular Crystallography
I03-Macromolecular Crystallography
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Christopher
Douse
,
Iva A.
Tchasovnikarova
,
Richard T.
Timms
,
Anna V.
Protasio
,
Marta
Seczynska
,
Daniil M.
Prigozhin
,
Anna
Albecka
,
James
Wagstaff
,
James C.
Williamson
,
Stefan M. V.
Freund
,
Paul J.
Lehner
,
Yorgo
Modis
Diamond Proposal Number(s):
[11235]
Open Access
Abstract: The HUSH complex represses retroviruses, transposons and genes to maintain the integrity of vertebrate genomes. HUSH regulates deposition of the epigenetic mark H3K9me3, but how its three core subunits — TASOR, MPP8 and Periphilin — contribute to assembly and targeting of the complex remains unknown. Here, we define the biochemical basis of HUSH assembly and find that its modular architecture resembles the yeast RNA-induced transcriptional silencing complex. TASOR, the central HUSH subunit, associates with RNA processing components. TASOR is required for H3K9me3 deposition over LINE-1 repeats and repetitive exons in transcribed genes. In the context of previous studies, this suggests that an RNA intermediate is important for HUSH activity. We dissect the TASOR and MPP8 domains necessary for transgene repression. Structure-function analyses reveal TASOR bears a catalytically-inactive PARP domain necessary for targeted H3K9me3 deposition. We conclude that TASOR is a multifunctional pseudo-PARP that directs HUSH assembly and epigenetic regulation of repetitive genomic targets.
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Oct 2020
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I03-Macromolecular Crystallography
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Open Access
Abstract: The human cis-prenyltransferase (hcis-PT) is an enzymatic complex essential for protein N-glycosylation. Synthesizing the precursor of the glycosyl carrier dolichol-phosphate, mutations in hcis-PT cause severe human diseases. Here, we reveal that hcis-PT exhibits a heterotetrameric assembly in solution, consisting of two catalytic dehydrodolichyl diphosphate synthase (DHDDS) and inactive Nogo-B receptor (NgBR) heterodimers. Importantly, the 2.3 Å crystal structure reveals that the tetramer assembles via the DHDDS C-termini as a dimer-of-heterodimers. Moreover, the distal C-terminus of NgBR transverses across the interface with DHDDS, directly participating in active-site formation and the functional coupling between the subunits. Finally, we explored the functional consequences of disease mutations clustered around the active-site, and in combination with molecular dynamics simulations, we propose a mechanism for hcis-PT dysfunction in retinitis pigmentosa. Together, our structure of the hcis-PT complex unveils the dolichol synthesis mechanism and its perturbation in disease.
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Oct 2020
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Krios I-Titan Krios I at Diamond
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Hannah R.
Bridges
,
Justin G.
Fedor
,
James N.
Blaza
,
Andrea
Di Luca
,
Alexander
Jussupow
,
Owen D.
Jarman
,
John J.
Wright
,
Ahmed-noor A.
Agip
,
Ana P.
Gamiz-hernandez
,
Maxie M.
Roessler
,
Ville R. I.
Kaila
,
Judy
Hirst
Diamond Proposal Number(s):
[16309]
Open Access
Abstract: Respiratory complex I (NADH:ubiquinone oxidoreductase) captures the free energy from oxidising NADH and reducing ubiquinone to drive protons across the mitochondrial inner membrane and power oxidative phosphorylation. Recent cryo-EM analyses have produced near-complete models of the mammalian complex, but leave the molecular principles of its long-range energy coupling mechanism open to debate. Here, we describe the 3.0-Å resolution cryo-EM structure of complex I from mouse heart mitochondria with a substrate-like inhibitor, piericidin A, bound in the ubiquinone-binding active site. We combine our structural analyses with both functional and computational studies to demonstrate competitive inhibitor binding poses and provide evidence that two inhibitor molecules bind end-to-end in the long substrate binding channel. Our findings reveal information about the mechanisms of inhibition and substrate reduction that are central for understanding the principles of energy transduction in mammalian complex I.
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Oct 2020
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I03-Macromolecular Crystallography
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Kuan-ying A.
Huang
,
Daming
Zhou
,
Elizabeth E.
Fry
,
Abhay
Kotecha
,
Peng-nien
Huang
,
Shu-li
Yang
,
Kuo-chien
Tsao
,
Yhu-chering
Huang
,
Tzou-yien
Lin
,
Jingshan
Ren
,
David I.
Stuart
Diamond Proposal Number(s):
[10627]
Open Access
Abstract: Enterovirus 71 (EV71)-neutralizing antibodies correlate with protection and have potential as therapeutic agents. We isolate and characterize a panel of plasmablast-derived monoclonal antibodies from an infected child whose antibody response focuses on the plateau epitope near the icosahedral 3-fold axes. Eight of a total of 19 antibodies target this epitope and three of these potently neutralize the virus. Representative neutralizing antibodies 38-1-10A and 38-3-11A both confer effective protection against lethal EV71 challenge in hSCARB2-transgenic mice. The cryo-electron microscopy structures of the EV71 virion in complex with Fab fragments of these potent and protective antibodies reveal the details of a conserved epitope formed by residues in the BC and HI loops of VP2 and the BC and HI loops of VP3 spanning the region around the 3-fold axis. Remarkably, the two antibodies interact with the epitope in quite distinct ways. These plateau-binding antibodies provide templates for promising candidate therapeutics.
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Oct 2020
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I04-1-Macromolecular Crystallography (fixed wavelength)
I04-Macromolecular Crystallography
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Alice
Douangamath
,
Daren
Fearon
,
Paul
Gehrtz
,
Tobias
Krojer
,
Petra
Lukacik
,
C. David
Owen
,
Efrat
Resnick
,
Claire
Strain-damerell
,
Anthony
Aimon
,
Péter
Ábrányi-balogh
,
Jose
Brandao-neto
,
Anna
Carbery
,
Gemma
Davison
,
Alexandre
Dias
,
Thomas D.
Downes
,
Louise
Dunnett
,
Michael
Fairhead
,
James D.
Firth
,
S. Paul
Jones
,
Aaron
Keeley
,
György M.
Keserü
,
Hanna F.
Klein
,
Mathew P.
Martin
,
Martin M.
Noble
,
Peter
O’brien
,
Ailsa
Powell
,
Rambabu N.
Reddi
,
Rachael
Skyner
,
Matthew
Snee
,
Michael J.
Waring
,
Conor
Wild
,
Nir
London
,
Frank
Von Delft
,
Martin A.
Walsh
Open Access
Abstract: COVID-19, caused by SARS-CoV-2, lacks effective therapeutics. Additionally, no antiviral drugs or vaccines were developed against the closely related coronavirus, SARS-CoV-1 or MERS-CoV, despite previous zoonotic outbreaks. To identify starting points for such therapeutics, we performed a large-scale screen of electrophile and non-covalent fragments through a combined mass spectrometry and X-ray approach against the SARS-CoV-2 main protease, one of two cysteine viral proteases essential for viral replication. Our crystallographic screen identified 71 hits that span the entire active site, as well as 3 hits at the dimer interface. These structures reveal routes to rapidly develop more potent inhibitors through merging of covalent and non-covalent fragment hits; one series of low-reactivity, tractable covalent fragments were progressed to discover improved binders. These combined hits offer unprecedented structural and reactivity information for on-going structure-based drug design against SARS-CoV-2 main protease.
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Oct 2020
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I03-Macromolecular Crystallography
I04-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
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Diamond Proposal Number(s):
[17221, 12579]
Open Access
Abstract: Human T-cell lymphotropic virus type 1 (HTLV-1) is a deltaretrovirus and the most oncogenic pathogen. Many of the ~20 million HTLV-1 infected people will develop severe leukaemia or an ALS-like motor disease, unless a therapy becomes available. A key step in the establishment of infection is the integration of viral genetic material into the host genome, catalysed by the retroviral integrase (IN) enzyme. Here, we use X-ray crystallography and single-particle cryo-electron microscopy to determine the structure of the functional deltaretroviral IN assembled on viral DNA ends and bound to the B56γ subunit of its human host factor, protein phosphatase 2 A. The structure reveals a tetrameric IN assembly bound to two molecules of the phosphatase via a conserved short linear motif. Insight into the deltaretroviral intasome and its interaction with the host will be crucial for understanding the pattern of integration events in infected individuals and therefore bears important clinical implications.
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Oct 2020
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