I03-Macromolecular Crystallography
I04-1-Macromolecular Crystallography (fixed wavelength)
I04-Macromolecular Crystallography
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Jurgen
Brem
,
Tharindi
Panduwawala
,
Jon Ulf
Hansen
,
Joanne
Hewitt
,
Edgars
Liepins
,
Pawel
Donets
,
Laura
Espina
,
Alistair J. M.
Farley
,
Kirill
Shubin
,
Gonzalo Gomez
Campillos
,
Paula
Kiuru
,
Shifali
Shishodia
,
Daniel
Krahn
,
Robert K.
Leśniak
,
Juliane
Schmidt
,
Karina
Calvopina
,
María-Carmen
Turrientes
,
Madeline E.
Kavanagh
,
Dmitrijs
Lubriks
,
Philip
Hinchliffe
,
Gareth W.
Langley
,
Ali F.
Aboklaish
,
Anders
Eneroth
,
Maria
Backlund
,
Andrei G.
Baran
,
Elisabet I.
Nielsen
,
Michael
Speake
,
Janis
Kuka
,
John
Robinson
,
Solveiga
Grinberga
,
Lindsay
Robinson
,
Michael A.
Mcdonough
,
Anna M.
Rydzik
,
Thomas M.
Leissing
,
Juan Carlos
Jimenez-Castellanos
,
Matthew B.
Avison
,
Solange
Da Silva Pinto
,
Andrew D.
Pannifer
,
Marina
Martjuga
,
Emma
Widlake
,
Martins
Priede
,
Iva
Hopkins Navratilova
,
Marek
Gniadkowski
,
Anna Karin
Belfrage
,
Peter
Brandt
,
Jari
Yli-Kauhaluoma
,
Eric
Bacque
,
Malcolm G. P.
Page
,
Fredrik
Björkling
,
Jonathan M.
Tyrrell
,
James
Spencer
,
Pauline A.
Lang
,
Pawel
Baranczewski
,
Rafael
Cantón
,
Stuart P.
Mcelroy
,
Philip S.
Jones
,
Fernando
Baquero
,
Edgars
Suna
,
Angus
Morrison
,
Timothy R.
Walsh
,
Christopher J.
Schofield
Open Access
Abstract: Carbapenems are vital antibiotics, but their efficacy is increasingly compromised by metallo-β-lactamases (MBLs). Here we report the discovery and optimization of potent broad-spectrum MBL inhibitors. A high-throughput screen for NDM-1 inhibitors identified indole-2-carboxylates (InCs) as potential β-lactamase stable β-lactam mimics. Subsequent structure–activity relationship studies revealed InCs as a new class of potent MBL inhibitor, active against all MBL classes of major clinical relevance. Crystallographic studies revealed a binding mode of the InCs to MBLs that, in some regards, mimics that predicted for intact carbapenems, including with respect to maintenance of the Zn(II)-bound hydroxyl, and in other regards mimics binding observed in MBL–carbapenem product complexes. InCs restore carbapenem activity against multiple drug-resistant Gram-negative bacteria and have a low frequency of resistance. InCs also have a good in vivo safety profile, and when combined with meropenem show a strong in vivo efficacy in peritonitis and thigh mouse infection models.
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Dec 2021
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I03-Macromolecular Crystallography
I04-Macromolecular Crystallography
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Diamond Proposal Number(s):
[17773]
Abstract: The combination of computational design and directed evolution could offer a general strategy to create enzymes with new functions. So far, this approach has delivered enzymes for a handful of model reactions. Here we show that new catalytic mechanisms can be engineered into proteins to accelerate more challenging chemical transformations. Evolutionary optimization of a primitive design afforded an efficient and enantioselective enzyme (BH32.14) for the Morita–Baylis–Hillman (MBH) reaction. BH32.14 is suitable for preparative-scale transformations, accepts a broad range of aldehyde and enone coupling partners and is able to promote selective monofunctionalizations of dialdehydes. Crystallographic, biochemical and computational studies reveal that BH32.14 operates via a sophisticated catalytic mechanism comprising a His23 nucleophile paired with a judiciously positioned Arg124. This catalytic arginine shuttles between conformational states to stabilize multiple oxyanion intermediates and serves as a genetically encoded surrogate of privileged bidentate hydrogen-bonding catalysts (for example, thioureas). This study demonstrates that elaborate catalytic devices can be built from scratch to promote demanding multi-step processes not observed in nature.
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Dec 2021
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I03-Macromolecular Crystallography
I04-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
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Alistair J.
Scott
,
Ai
Niitsu
,
Huong T.
Kratochvil
,
Eric J. M.
Lang
,
Jason T.
Sengel
,
William M.
Dawson
,
Kozhinjampara R.
Mahendran
,
Marco
Mravic
,
Andrew
Thomson
,
R. Leo
Brady
,
Lijun
Liu
,
Adrian J.
Mulholland
,
Hagan
Bayley
,
William F.
Degrado
,
Mark I.
Wallace
,
Derek N.
Woolfson
Abstract: The design of peptides that assemble in membranes to form functional ion channels is challenging. Specifically, hydrophobic interactions must be designed between the peptides and at the peptide–lipid interfaces simultaneously. Here, we take a multi-step approach towards this problem. First, we use rational de novo design to generate water-soluble α-helical barrels with polar interiors, and confirm their structures using high-resolution X-ray crystallography. These α-helical barrels have water-filled lumens like those of transmembrane channels. Next, we modify the sequences to facilitate their insertion into lipid bilayers. Single-channel electrical recordings and fluorescent imaging of the peptides in membranes show monodisperse, cation-selective channels of unitary conductance. Surprisingly, however, an X-ray structure solved from the lipidic cubic phase for one peptide reveals an alternative state with tightly packed helices and a constricted channel. To reconcile these observations, we perform computational analyses to compare the properties of possible different states of the peptide.
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May 2021
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I15-1-X-ray Pair Distribution Function (XPDF)
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Bikash Kumar
Shaw
,
Ashlea R.
Hughes
,
Maxime
Ducamp
,
Stephen
Moss
,
Anup
Debnath
,
Adam F.
Sapnik
,
Michael F.
Thorne
,
Lauren N.
Mchugh
,
Andrea
Pugliese
,
Dean S.
Keeble
,
Philip
Chater
,
Juan M.
Bermudez-Garcia
,
Xavier
Moya
,
Shyamal K.
Saha
,
David A.
Keen
,
François-Xavier
Coudert
,
Frédéric
Blanc
,
Thomas
Bennett
Diamond Proposal Number(s):
[20038]
Abstract: Several organic–inorganic hybrid materials from the metal–organic framework (MOF) family have been shown to form stable liquids at high temperatures. Quenching then results in the formation of melt-quenched MOF glasses that retain the three-dimensional coordination bonding of the crystalline phase. These hybrid glasses have intriguing properties and could find practical applications, yet the melt-quench phenomenon has so far remained limited to a few MOF structures. Here we turn to hybrid organic–inorganic perovskites—which occupy a prominent position within materials chemistry owing to their functional properties such as ion transport, photoconductivity, ferroelectricity and multiferroicity—and show that a series of dicyanamide-based hybrid organic–inorganic perovskites undergo melting. Our combined experimental–computational approach demonstrates that, on quenching, they form glasses that largely retain their solid-state inorganic–organic connectivity. The resulting materials show very low thermal conductivities (~0.2 W m−1 K−1), moderate electrical conductivities (10−3–10−5 S m−1) and polymer-like thermomechanical properties.
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May 2021
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B18-Core EXAFS
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Diamond Proposal Number(s):
[14239]
Abstract: Platinum functions exceptionally well as a nanoparticulate catalyst in many important fields, such as in the removal of atmospheric pollutants, but it is scarce, expensive and not always sufficiently durable. Here, we report a perovskite system in which 0.5 wt% Pt is integrated into the support and its subsequent conversion through exsolution to achieve a resilient catalyst. Owing to the instability of most Pt oxides at high temperatures, a thermally stable platinum oxide precursor, barium platinate, was used to preserve the platinum as an oxide during the solid-state synthesis in an approach akin to the Trojan horse legend. By tailoring the procedure, it is possible to produce a uniform equilibrated structure with active emergent Pt nanoparticles strongly embedded in the perovskite surface that display better CO oxidation activity and stability than those of conventionally prepared Pt catalysts. This catalyst was further evaluated for a variety of reactions under realistic test environments—CO and NO oxidation, diesel oxidation catalysis and ammonia slip reactions were investigated.
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May 2021
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[17379]
Abstract: Current strategies for the synthesis of molecular knots focus on twisting, folding and/or threading molecular building blocks. Here we report that Zn(II) or Fe(II) ions can be used to weave ligand strands to form a woven 3 × 3 molecular grid. We found that the process requires tetrafluoroborate anions to template the assembly of the interwoven grid by binding within the square cavities formed between the metal-coordinated criss-crossed ligands. The strand ends of the grid can subsequently be joined through within-grid alkene metathesis reactions to form a topologically trivial macrocycle (unknot), a doubly interlocked [2]catenane (Solomon link) and a knot with seven crossings in a 258-atom-long closed loop. This 74 knot topology corresponds to that of an endless knot, which is a basic motif of Celtic interlace, the smallest Chinese knot and one of the eight auspicious symbols of Buddhism and Hinduism. The weaving of molecular strands within a discrete layer by anion-template metal–ion coordination opens the way for the synthesis of other molecular knot topologies and to woven polymer materials.
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Dec 2020
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B18-Core EXAFS
E01-JEM ARM 200CF
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Xi
Sun
,
Simon R.
Dawson
,
Tanja E.
Parmentier
,
Grazia
Malta
,
Thomas E.
Davies
,
Qian
He
,
Li
Lu
,
David J.
Morgan
,
Nicholas
Carthey
,
Peter
Johnston
,
Simon A.
Kondrat
,
Simon J.
Freakley
,
Christopher J.
Kiely
,
Graham J.
Hutchings
Diamond Proposal Number(s):
[22766, 20643, 19580]
Abstract: Single-site catalysts can demonstrate high activity and selectivity in many catalytic reactions. The synthesis of these materials by impregnation from strongly oxidizing aqueous solutions or pH-controlled deposition often leads to low metal loadings or a range of metal species. Here, we demonstrate that simple impregnation of the metal precursors onto activated carbon from a low-boiling-point, low-polarity solvent, such as acetone, results in catalysts with an atomic dispersion of cationic metal species. We show the generality of this method by producing single-site Au, Pd, Ru and Pt catalysts supported on carbon in a facile manner. Single-site Au/C catalysts have previously been validated commercially to produce vinyl chloride, and here we show that this facile synthesis method can produce effective catalysts for acetylene hydrochlorination in the absence of the highly oxidizing acidic solvents previously used.
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Apr 2020
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I03-Macromolecular Crystallography
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Danai S.
Gkotsi
,
Hannes
Ludewig
,
Sunil V.
Sharma
,
Jack A.
Connolly
,
Jagwinder
Dhaliwal
,
Yunpeng
Wang
,
William P.
Unsworth
,
Richard J. K.
Taylor
,
Matthew M. W.
Mclachlan
,
Stephen
Shanahan
,
James
Naismith
,
Rebecca J. M.
Goss
Diamond Proposal Number(s):
[14980]
Abstract: Oceanic cyanobacteria are the most abundant oxygen-generating phototrophs on our planet and are therefore important to life. These organisms are infected by viruses called cyanophages, which have recently shown to encode metabolic genes that modulate host photosynthesis, phosphorus cycling and nucleotide metabolism. Herein we report the characterization of a wild-type flavin-dependent viral halogenase (VirX1) from a cyanophage. Notably, halogenases have been previously associated with secondary metabolism, tailoring natural products. Exploration of this viral halogenase reveals it capable of regioselective halogenation of a diverse range of substrates with a preference for forming aryl iodide species; this has potential implications for the metabolism of the infected host. Until recently, a flavin-dependent halogenase that is capable of iodination in vitro had not been reported. VirX1 is interesting from a biocatalytic perspective as it shows strikingly broad substrate flexibility and a clear preference for iodination, as illustrated by kinetic analysis. These factors together render it an attractive tool for synthesis.
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Oct 2019
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I11-High Resolution Powder Diffraction
I19-Small Molecule Single Crystal Diffraction
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Xiaoyan
Wang
,
Linjiang
Chen
,
Samantha Y.
Chong
,
Marc A.
Little
,
Yongzhen
Wu
,
Wei-Hong
Zhu
,
Rob
Clowes
,
Yong
Yan
,
Martijn A.
Zwijnenburg
,
Reiner Sebastian
Sprick
,
Andrew I.
Cooper
Diamond Proposal Number(s):
[15777, 17193]
Abstract: Nature uses organic molecules for light harvesting and photosynthesis, but most man-made water splitting catalysts are inorganic semiconductors. Organic photocatalysts, while attractive because of their synthetic tunability, tend to have low quantum efficiencies for water splitting. Here we present a crystalline covalent organic framework (COF) based on a benzo-bis(benzothiophene sulfone) moiety that shows a much higher activity for photochemical hydrogen evolution than its amorphous or semicrystalline counterparts. The COF is stable under long-term visible irradiation and shows steady photochemical hydrogen evolution with a sacrificial electron donor for at least 50 hours. We attribute the high quantum efficiency of fused-sulfone-COF to its crystallinity, its strong visible light absorption, and its wettable, hydrophilic 3.2 nm mesopores. These pores allow the framework to be dye-sensitized, leading to a further 61% enhancement in the hydrogen evolution rate up to 16.3 mmol g−1 h−1. The COF also retained its photocatalytic activity when cast as a thin film onto a support.
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Oct 2018
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I11-High Resolution Powder Diffraction
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Kasper S.
Pedersen
,
Panagiota
Perlepe
,
Michael L.
Aubrey
,
Daniel N.
Woodruff
,
Sebastian E.
Reyes-Lillo
,
Anders
Reinholdt
,
Laura
Voigt
,
Zheshen
Li
,
Kasper
Borup
,
Mathieu
Rouzières
,
Dumitru
Samohvalov
,
Fabrice
Wilhelm
,
Andrei
Rogalev
,
Jeffrey B.
Neaton
,
Jeffrey R.
Long
,
Rodolphe
Clérac
Diamond Proposal Number(s):
[13284]
Abstract: The unique properties of graphene, transition-metal dichalcogenides and other two-dimensional (2D) materials have boosted interest in layered coordination solids. In particular, 2D materials that behave as both conductors and magnets could find applications in quantum magnetoelectronics and spintronics. Here, we report the synthesis of CrCl2(pyrazine)2, an air-stable layered solid, by reaction of CrCl2 with pyrazine (pyz). This compound displays a ferrimagnetic order below ∼55 K, reflecting the presence of strong magnetic interactions. Electrical conductivity measurements demonstrate that CrCl2(pyz)2 reaches a conductivity of 32 mS cm–1 at room temperature, which operates through a 2D hopping-based transport mechanism. These properties are induced by the redox-activity of the pyrazine ligand, which leads to a smearing of the Cr 3d and pyrazine π states. We suggest that the combination of redox-active ligands and reducing paramagnetic metal ions represents a general approach towards tuneable 2D materials that consist of charge-neutral layers and exhibit both long-range magnetic order and high electronic conductivity.
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Oct 2018
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