I03-Macromolecular Crystallography
I04-1-Macromolecular Crystallography (fixed wavelength)
I04-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
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Diamond Proposal Number(s):
[18069]
Open Access
Abstract: ADP-ribosyltransferases use NAD+ to catalyse substrate ADP-ribosylation1, and thereby regulate cellular pathways or contribute to toxin-mediated pathogenicity of bacteria2,3,4. Reversible ADP-ribosylation has traditionally been considered a protein-specific modification5, but recent in vitro studies have suggested nucleic acids as targets6,7,8,9. Here we present evidence that specific, reversible ADP-ribosylation of DNA on thymidine bases occurs in cellulo through the DarT–DarG toxin–antitoxin system, which is found in a variety of bacteria (including global pathogens such as Mycobacterium tuberculosis, enteropathogenic Escherichia coli and Pseudomonas aeruginosa)10. We report the structure of DarT, which identifies this protein as a diverged member of the PARP family. We provide a set of high-resolution structures of this enzyme in ligand-free and pre- and post-reaction states, which reveals a specialized mechanism of catalysis that includes a key active-site arginine that extends the canonical ADP-ribosyltransferase toolkit. Comparison with PARP–HPF1, a well-established DNA repair protein ADP-ribosylation complex, offers insights into how the DarT class of ADP-ribosyltransferases evolved into specific DNA-modifying enzymes. Together, our structural and mechanistic data provide details of this PARP family member and contribute to a fundamental understanding of the ADP-ribosylation of nucleic acids. We also show that thymine-linked ADP-ribose DNA adducts reversed by DarG antitoxin (functioning as a noncanonical DNA repair factor) are used not only for targeted DNA damage to induce toxicity, but also as a signalling strategy for cellular processes. Using M. tuberculosis as an exemplar, we show that DarT–DarG regulates growth by ADP-ribosylation of DNA at the origin of chromosome replication.
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Aug 2021
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I03-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
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Johannes Gregor Matthias
Rack
,
Qiang
Liu
,
Valentina
Zorzini
,
Jim
Voorneveld
,
Antonio
Ariza
,
Kourosh
Honarmand Ebrahimi
,
Julia M.
Reber
,
Sarah C.
Krassnig
,
Dragana
Ahel
,
Gijsbert A.
Van Der Marel
,
Aswin
Mangerich
,
James S. O.
Mccullagh
,
Dmitri V.
Filippov
,
Ivan
Ahel
Diamond Proposal Number(s):
[18069, 23459]
Open Access
Abstract: Poly(ADP-ribosyl)ation (PAR) is a versatile and complex posttranslational modification composed of repeating units of ADP-ribose arranged into linear or branched polymers. This scaffold is linked to the regulation of many of cellular processes including the DNA damage response, alteration of chromatin structure and Wnt signalling. Despite decades of research, the principles and mechanisms underlying all steps of PAR removal remain actively studied. In this work, we synthesise well-defined PAR branch point molecules and demonstrate that PARG, but not ARH3, can resolve this distinct PAR architecture. Structural analysis of ARH3 in complex with dimeric ADP-ribose as well as an ADP-ribosylated peptide reveal the molecular basis for the hydrolysis of linear and terminal ADP-ribose linkages. We find that ARH3-dependent hydrolysis requires both rearrangement of a catalytic glutamate and induction of an unusual, square-pyramidal magnesium coordination geometry.
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Jul 2021
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I04-1-Macromolecular Crystallography (fixed wavelength)
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Dávid
Bajusz
,
Warren S.
Wade
,
Grzegorz
Satała
,
Andrzej J.
Bojarski
,
Janez
Ilaš
,
Jessica
Ebner
,
Florian
Grebien
,
Henrietta
Papp
,
Ferenc
Jakab
,
Alice
Douangamath
,
Daren
Fearon
,
Frank
Von Delft
,
Marion
Schuller
,
Ivan
Ahel
,
Amanda
Wakefield
,
Sándor
Vajda
,
János
Gerencsér
,
Péter
Pallai
,
György M.
Keserű
Diamond Proposal Number(s):
[27001, 18145, 27963]
Open Access
Abstract: Fragment-based drug design has introduced a bottom-up process for drug development, with improved sampling of chemical space and increased effectiveness in early drug discovery. Here, we combine the use of pharmacophores, the most general concept of representing drug-target interactions with the theory of protein hotspots, to develop a design protocol for fragment libraries. The SpotXplorer approach compiles small fragment libraries that maximize the coverage of experimentally confirmed binding pharmacophores at the most preferred hotspots. The efficiency of this approach is demonstrated with a pilot library of 96 fragment-sized compounds (SpotXplorer0) that is validated on popular target classes and emerging drug targets. Biochemical screening against a set of GPCRs and proteases retrieves compounds containing an average of 70% of known pharmacophores for these targets. More importantly, SpotXplorer0 screening identifies confirmed hits against recently established challenging targets such as the histone methyltransferase SETD2, the main protease (3CLPro) and the NSP3 macrodomain of SARS-CoV-2.
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May 2021
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I04-1-Macromolecular Crystallography (fixed wavelength)
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Marion
Schuller
,
Galen J.
Correy
,
Stefan
Gahbauer
,
Daren
Fearon
,
Taiasean
Wu
,
Roberto Efraín
Díaz
,
Iris D.
Young
,
Luan
Carvalho Martins
,
Dominique H.
Smith
,
Ursula
Schulze-Gahmen
,
Tristan W.
Owens
,
Ishan
Deshpande
,
Gregory E.
Merz
,
Aye C.
Thwin
,
Justin T.
Biel
,
Jessica K.
Peters
,
Michelle
Moritz
,
Nadia
Herrera
,
Huong T.
Kratochvil
,
Anthony
Aimon
,
James
Bennett
,
Jose
Brandao Neto
,
Aina E.
Cohen
,
Alexandre
Dias
,
Alice
Douangamath
,
Louise
Dunnett
,
Oleg
Fedorov
,
Matteo P.
Ferla
,
Martin R.
Fuchs
,
Tyler J.
Gorrie-Stone
,
James M.
Holton
,
Michael G.
Johnson
,
Tobias
Krojer
,
George
Meigs
,
Alisa J.
Powell
,
Johannes Gregor Matthias
Rack
,
Victor
Rangel
,
Silvia
Russi
,
Rachael E.
Skyner
,
Clyde A.
Smith
,
Alexei S.
Soares
,
Jennifer L.
Wierman
,
Kang
Zhu
,
Peter
O’brien
,
Natalia
Jura
,
Alan
Ashworth
,
John J.
Irwin
,
Michael C.
Thompson
,
Jason E.
Gestwicki
,
Frank
Von Delft
,
Brian K.
Shoichet
,
James S.
Fraser
,
Ivan
Ahel
Diamond Proposal Number(s):
[27001]
Open Access
Abstract: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) macrodomain within the nonstructural protein 3 counteracts host-mediated antiviral adenosine diphosphate–ribosylation signaling. This enzyme is a promising antiviral target because catalytic mutations render viruses nonpathogenic. Here, we report a massive crystallographic screening and computational docking effort, identifying new chemical matter primarily targeting the active site of the macrodomain. Crystallographic screening of 2533 diverse fragments resulted in 214 unique macrodomain-binders. An additional 60 molecules were selected from docking more than 20 million fragments, of which 20 were crystallographically confirmed. X-ray data collection to ultra-high resolution and at physiological temperature enabled assessment of the conformational heterogeneity around the active site. Several fragment hits were confirmed by solution binding using three biophysical techniques (differential scanning fluorimetry, homogeneous time-resolved fluorescence, and isothermal titration calorimetry). The 234 fragment structures explore a wide range of chemotypes and provide starting points for development of potent SARS-CoV-2 macrodomain inhibitors.
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Apr 2021
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I03-Macromolecular Crystallography
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Diamond Proposal Number(s):
[27001]
Open Access
Abstract: Viral macrodomains possess the ability to counteract host ADP-ribosylation, a post-translational modification implicated in the creation of an antiviral environment via immune response regulation. This brought them into focus as promising therapeutic targets, albeit the close homology to some of the human macrodomains raised concerns regarding potential cross-reactivity and adverse effects for the host. Here, we evaluate the structure and function of the macrodomain of SARS-CoV-2, the causative agent of COVID-19. We show that it can antagonize ADP-ribosylation by PARP14, a cellular (ADP-ribosyl)transferase necessary for the restriction of coronaviral infections. Furthermore, our structural studies together with ligand modelling revealed the structural basis for poly(ADP-ribose) binding and hydrolysis, an emerging new aspect of viral macrodomain biology. These new insights were used in an extensive evolutionary analysis aimed at evaluating the druggability of viral macrodomains not only from the Coronaviridae but also Togaviridae and Iridoviridae genera (causing diseases such as Chikungunya and infectious spleen and kidney necrosis virus disease, respectively). We found that they contain conserved features, distinct from their human counterparts, which may be exploited during drug design.
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Nov 2020
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I03-Macromolecular Crystallography
I04-1-Macromolecular Crystallography (fixed wavelength)
I04-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
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Marcin J.
Suskiewicz
,
Florian
Zobel
,
Tom E. H.
Ogden
,
Pietro
Fontana
,
Antonio
Ariza
,
Ji-Chun
Yang
,
Kang
Zhu
,
Lily
Bracken
,
William J.
Hawthorne
,
Dragana
Ahel
,
David
Neuhaus
,
Ivan
Ahel
Diamond Proposal Number(s):
[9306, 18069]
Abstract: The anti-cancer drug target poly(ADP-ribose) polymerase 1 (PARP1) and its close homologue, PARP2, are early responders to DNA damage in human cells1,2. Upon binding to genomic lesions, these enzymes utilise NAD+ to modify a plethora of proteins with mono- and poly(ADP-ribose) signals that are important for subsequent chromatin decompaction and repair factor recruitment3,4. These post-translational modification events are predominantly serine-linked and require HPF1, an accessory factor that is specific for the DNA damage response and switches the amino-acid specificity of PARP1/2 from aspartate/glutamate to serine residues5–10. Here, we report a co-structure of HPF1 bound to the catalytic domain of PARP2 that, in combination with NMR and biochemical data, reveals a composite active site formed by residues from both PARP1/2 and HPF1. We further show that the assembly of this new catalytic centre is essential for DNA damage-induced protein ADP-ribosylation in human cells. In response to DNA damage and NAD+ binding site occupancy, the HPF1–PARP1/2 interaction is enhanced via allosteric networks operating within PARP1/2, providing an additional level of regulation in DNA repair induction. As HPF1 forms a joint active site with PARP1/2, our data implicate HPF1 as an important determinant of the response to clinical PARP inhibitors.
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Feb 2020
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I03-Macromolecular Crystallography
I04-1-Macromolecular Crystallography (fixed wavelength)
I04-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
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Diamond Proposal Number(s):
[18069]
Open Access
Abstract: Protein ADP-ribosylation is a highly dynamic post-translational modification. The rapid turnover is achieved, among others, by ADP-(ribosyl)hydrolases (ARHs), an ancient family of enzymes that reverses this modification. Recently ARHs came into focus due to their role as regulators of cellular stresses and tumor suppressors. Here we present a comprehensive structural analysis of the enzymatically active family members ARH1 and ARH3. These two enzymes have very distinct substrate requirements. Our data show that binding of the adenosine ribose moiety is highly diverged between the two enzymes, whereas the active sites harboring the distal ribose closely resemble each other. Despite this apparent similarity, we elucidate the structural basis for the selective inhibition of ARH3 by the ADP-ribose analogues ADP-HPD and arginine-ADP-ribose. Together, our biochemical and structural work provides important insights into the mode of enzyme-ligand interaction, helps to understand differences in their catalytic behavior, and provides useful tools for targeted drug design.
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Nov 2018
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B23-Circular Dichroism
I04-Macromolecular Crystallography
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Dominika
Kwasna
,
Syed Arif
Abdul Rehman
,
Jayaprakash
Natarajan
,
Stephen
Matthews
,
Ross
Madden
,
Virginia
De Cesare
,
Simone
Weidlich
,
Satpal
Virdee
,
Ivan
Ahel
,
Ian
Gibbs-seymour
,
Yogesh
Kulathu
Diamond Proposal Number(s):
[16778]
Open Access
Abstract: Deubiquitinating enzymes (DUBs) are important regulators of ubiquitin signaling. Here, we report the discovery of deubiquitinating activity in ZUFSP/C6orf113. High-resolution crystal structures of ZUFSP in complex with ubiquitin reveal several distinctive features of ubiquitin recognition and catalysis. Our analyses reveal that ZUFSP is a novel DUB with no homology to any known DUBs, leading us to classify ZUFSP as the seventh DUB family. Intriguingly, the minimal catalytic domain does not cleave polyubiquitin. We identify two ubiquitin binding domains in ZUFSP: a ZHA (ZUFSP helical arm) that binds to the distal ubiquitin and an atypical UBZ domain in ZUFSP that binds to polyubiquitin. Importantly, both domains are essential for ZUFSP to selectively cleave K63-linked polyubiquitin. We show that ZUFSP localizes to DNA lesions, where it plays an important role in genome stability pathways, functioning to prevent spontaneous DNA damage and also promote cellular survival in response to exogenous DNA damage.
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Mar 2018
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I02-Macromolecular Crystallography
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Marion
Schuller
,
Kerstin
Riedel
,
Ian
Gibbs-seymour
,
Kristin
Uth
,
Christian
Sieg
,
André P
Gehring
,
Ivan
Ahel
,
Franz
Bracher
,
Benedikt M.
Kessler
,
Jonathan M.
Elkins
,
Stefan
Knapp
Abstract: Macrodomains are conserved protein interaction modules that can be found in all domains of life as well as in certain viruses. Macrodomains mediate recognition of sequence motifs harbouring adenosine diphosphate ribose (ADPR) modifications, thereby regulating a variety of cellular processes. Due to their role in cancer or viral pathogenesis, macrodomains have emerged as potential therapeutic targets, but the unavailability of small molecule inhibitors has hampered target validation studies so far. Here, we describe an efficient screening strategy for identification of small molecule inhibitors that displace ADPR from macrodomains. We report the discovery and characterisation of a macrodomain inhibitor, GeA-69, selectively targeting macrodomain 2 (MD2) of PARP14 with low micromolar affinity. Co-crystallisation of a GeA-69 analogue with PARP14 MD2 revealed an allosteric binding mechanism explaining its selectivity over other human macrodomains. We show that GeA-69 engages PARP14 MD2 in intact cells and prevents its localisation to sites of DNA damage.
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Oct 2017
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I02-Macromolecular Crystallography
I04-1-Macromolecular Crystallography (fixed wavelength)
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Diamond Proposal Number(s):
[9306, 12346]
Open Access
Abstract: The discovery and study of toxin-antitoxin (TA) systems helps us advance our understanding of the strategies prokaryotes employ to regulate cellular processes related to the general stress response, such as defense against phages, growth control, biofilm formation, persistence, and programmed cell death. Here we identify and characterize a TA system found in various bacteria, including the global pathogen Mycobacterium tuberculosis. The toxin of the system (DarT) is a domain of unknown function (DUF) 4433, and the antitoxin (DarG) a macrodomain protein. We demonstrate that DarT is an enzyme that specifically modifies thymidines on single-stranded DNA in a sequence-specific manner by a nucleotide-type modification called ADP-ribosylation. We also show that this modification can be removed by DarG. Our results provide an example of reversible DNA ADP-ribosylation, and we anticipate potential therapeutic benefits by targeting this enzyme-enzyme TA system in bacterial pathogens such as M. tuberculosis.
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Dec 2016
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