I04-Macromolecular Crystallography
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Diamond Proposal Number(s):
[23281]
Open Access
Abstract: The phosphatidylinositol 5-phosphate 4-kinases (PI5P4Ks) play a central role in regulating cell signalling pathways and, as such, have become therapeutic targets for diseases such as cancer, neurodegeneration and immunological disorders. Many of the PI5P4Kα inhibitors that have been reported to date have suffered from poor selectivity and/or potency and the availability of better tool molecules would facilitate biological exploration. Herein we report a novel PI5P4Kα inhibitor chemotype that was identified through virtual screening. The series was optimised to deliver ARUK2002821 (36), a potent PI5P4Kα inhibitor (pIC50 = 8.0) which is selective vs other PI5P4K isoforms and has broad selectivity against lipid and protein kinases. ADMET and target engagement data are provided for this tool molecule and others in the series, as well as an X-ray structure of 36 solved in complex with its PI5P4Kα target.
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Apr 2023
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I02-Macromolecular Crystallography
I04-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
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Diamond Proposal Number(s):
[14043, 18548]
Open Access
Abstract: CK2 is a ubiquitous protein kinase with an anti-apoptotic role and is found to be overexpressed in multiple cancer types. To this end, the inhibition of CK2 is of great interest with regard to the development of novel anti-cancer therapeutics. ATP-site inhibition of CK2 is possible; however, this typically results in poor selectivity due to the highly conserved nature of the catalytic site amongst kinases. An alternative methodology for the modulation of CK2 activity is through allosteric inhibition. The recently identified αD site represents a promising binding site for allosteric inhibition of CK2α. The work presented herein describes the development of a series of CK2α allosteric inhibitors through iterative cycles of X-ray crystallography and enzymatic assays, in addition to both fragment growing and fragment merging design strategies. The lead fragment developed, fragment 8, exhibits a high ligand efficiency, displays no drop off in activity between enzymatic and cellular assays, and successfully engages CK2α in cells. Furthermore, X-ray crystallographic analysis provided indications towards a novel mechanism of allosteric inhibition through αD site binding. Fragments described in this paper therefore represent promising starting points for the development of highly selective allosteric CK2 inhibitors.
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Sep 2022
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I03-Macromolecular Crystallography
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Christopher R.
Smith
,
Svitlana
Kulyk
,
Misbha Ud Din
Ahmad
,
Valentina
Arkhipova
,
James G.
Christensen
,
Robin J.
Gunn
,
Anthony
Ivetac
,
John M.
Ketcham
,
Jon
Kuehler
,
J. David
Lawson
,
Nicole C.
Thomas
,
Xiaolun
Wang
,
Matthew A.
Marx
Open Access
Abstract: Here we describe the early stages of a fragment-based lead discovery (FBLD) project for a recently elucidated synthetic lethal target, the PRMT5/MTA complex, for the treatment of MTAP-deleted cancers. Starting with five fragment/PRMT5/MTA X-ray co-crystal structures, we employed a two-phase fragment elaboration process encompassing optimization of fragment hits and subsequent fragment growth to increase potency, assess synthetic tractability, and enable structure-based drug design. Two lead series were identified, one of which led to the discovery of the clinical candidate MRTX1719.
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Sep 2022
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I03-Macromolecular Crystallography
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Huiyong
Ma
,
James B.
Murray
,
Huadong
Luo
,
Xuemin
Cheng
,
Qiuxia
Chen
,
Chao
Song
,
Cong
Duan
,
Ping
Tan
,
Lifang
Zhang
,
Jian
Liu
,
Barry A.
Morgan
,
Jin
Li
,
Jinqiao
Wan
,
Lisa M.
Baker
,
William
Finnie
,
Lucie
Guetzoyan
,
Richard
Harris
,
Nicole
Hendrickson
,
Natalia
Matassova
,
Heather
Simmonite
,
Julia
Smith
,
Roderick E.
Hubbard
,
Guansai
Liu
Diamond Proposal Number(s):
[29348]
Open Access
Abstract: We describe a novel approach for screening fragments against a protein that combines the sensitivity of DNA-encoded library technology with the ability of fragments to explore what will bind. Each of the members of the library consists of a fragment which is linked to a photoactivatable diazirine moiety. Split and pool synthesis combines each fragment with a set of linkers with the version of the library reported here containing some 70k different compounds, each with an individual DNA code. Incubation of the library with a protein sample is followed by photoactivation, washing and subsequent PCR and sequencing which allows the individual fragment hits to be identified. We illustrate how the approach allows successful hit fragment identification using only microgram quantities of material for two targets. PAK4 is a kinase for which conventional fragment screening has generated many advance leads. The as yet undrugged target, 2-epimerase, presents a more challenging active site for identification of hit compounds. In both cases, PAC-FragmentDEL identified fragments validated as hits by ligand-observed NMR measurements and crystal structure determination of off-DNA sample binding to the proteins.
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Aug 2022
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Susanne
Müller
,
Suzanne
Ackloo
,
Arij
Al Chawaf
,
Bissan
Al-Lazikani
,
Albert
Antolin
,
Jonathan B.
Baell
,
Hartmut
Beck
,
Shaunna
Beedie
,
Ulrich A. K.
Betz
,
Gustavo
Arruda Bezerra
,
Paul E.
Brennan
,
David
Brown
,
Peter J.
Brown
,
Alex N.
Bullock
,
Adrian J.
Carter
,
Apirat
Chaikuad
,
Mathilde
Chaineau
,
Alessio
Ciulli
,
Ian
Collins
,
Jan
Dreher
,
David
Drewry
,
Kristina
Edfeldt
,
Aled M.
Edwards
,
Ursula
Egner
,
Stephen V.
Frye
,
Stephen M.
Fuchs
,
Matthew D.
Hall
,
Ingo V.
Hartung
,
Alexander
Hillisch
,
Stephen H.
Hitchcock
,
Evert
Homan
,
Natarajan
Kannan
,
James R.
Kiefer
,
Stefan
Knapp
,
Milka
Kostic
,
Stefan
Kubicek
,
Andrew S.
Leach
,
Sven
Lindemann
,
Brian D.
Marsden
,
Hisanori
Matsui
,
Jordan L.
Meier
,
Daniel
Merk
,
Maurice
Michel
,
Maxwell R.
Morgan
,
Anke
Mueller-Fahrnow
,
Dafydd R.
Owen
,
Benjamin G.
Perry
,
Saul H.
Rosenberg
,
Kumar Singh
Saikatendu
,
Matthieu
Schapira
,
Cora
Scholten
,
Sujata
Sharma
,
Anton
Simeonov
,
Michael
Sundström
,
Giulio
Superti-Furga
,
Matthew H.
Todd
,
Claudia
Tredup
,
Masoud
Vedadi
,
Frank
Von Delft
,
Timothy M.
Willson
,
Georg E.
Winter
,
Paul
Workman
,
Cheryl H.
Arrowsmith
Open Access
Abstract: Twenty years after the publication of the first draft of the human genome, our knowledge of the human proteome is still fragmented. The challenge of translating the wealth of new knowledge from genomics into new medicines is that proteins, and not genes, are the primary executers of biological function. Therefore, much of how biology works in health and disease must be understood through the lens of protein function. Accordingly, a subset of human proteins has been at the heart of research interests of scientists over the centuries, and we have accumulated varying degrees of knowledge about approximately 65% of the human proteome. Nevertheless, a large proportion of proteins in the human proteome (∼35%) remains uncharacterized, and less than 5% of the human proteome has been successfully targeted for drug discovery. This highlights the profound disconnect between our abilities to obtain genetic information and subsequent development of effective medicines. Target 2035 is an international federation of biomedical scientists from the public and private sectors, which aims to address this gap by developing and applying new technologies to create by year 2035 chemogenomic libraries, chemical probes, and/or biological probes for the entire human proteome.
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Dec 2021
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I02-Macromolecular Crystallography
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Mostafa
Jamshidiha
,
Thomas
Lanyon-Hogg
,
Charlotte L.
Sutherell
,
Gregory B.
Craven
,
Montse
Tersa
,
Elena
De Vita
,
Delia
Brustur
,
Inmaculada
Perez-Dorado
,
Sarah
Hassan
,
Rita
Petracca
,
Rhodri M.
Morgan
,
Máximo
Sanz-Hernández
,
Jim C.
Norman
,
Alan
Armstrong
,
David J.
Mann
,
Ernesto
Cota
,
Edward W.
Tate
Diamond Proposal Number(s):
[17221, 23620]
Open Access
Abstract: Rab27A is a small GTPase, which mediates transport and docking of secretory vesicles at the plasma membrane via protein–protein interactions (PPIs) with effector proteins. Rab27A promotes the growth and invasion of multiple cancer types such as breast, lung and pancreatic, by enhancing secretion of chemokines, metalloproteases and exosomes. The significant role of Rab27A in multiple cancer types and the minor role in adults suggest that Rab27A may be a suitable target to disrupt cancer metastasis. Similar to many GTPases, the flat topology of the Rab27A-effector PPI interface and the high affinity for GTP make it a challenging target for inhibition by small molecules. Reported co-crystal structures show that several effectors of Rab27A interact with the Rab27A SF4 pocket (‘WF-binding pocket’) via a conserved tryptophan–phenylalanine (WF) dipeptide motif. To obtain structural insight into the ligandability of this pocket, a novel construct was designed fusing Rab27A to part of an effector protein (fRab27A), allowing crystallisation of Rab27A in high throughput. The paradigm of KRas covalent inhibitor development highlights the challenge presented by GTPase proteins as targets. However, taking advantage of two cysteine residues, C123 and C188, that flank the WF pocket and are unique to Rab27A and Rab27B among the >60 Rab family proteins, we used the quantitative Irreversible Tethering (qIT) assay to identify the first covalent ligands for native Rab27A. The binding modes of two hits were elucidated by co-crystallisation with fRab27A, exemplifying a platform for identifying suitable lead fragments for future development of competitive inhibitors of the Rab27A-effector interaction interface, corroborating the use of covalent libraries to tackle challenging targets.
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Dec 2021
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I04-Macromolecular Crystallography
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Christopher J.
Matheson
,
Christopher R.
Coxon
,
Richard
Bayliss
,
Kathy
Boxall
,
Benoit
Carbain
,
Andrew M.
Fry
,
Ian R.
Hardcastle
,
Suzannah J.
Harnor
,
Corine
Mas-Droux
,
David R.
Newell
,
Mark W.
Richards
,
Mangaleswaran
Sivaprakasam
,
David
Turner
,
Roger J.
Griffin
,
Bernard T.
Golding
,
Céline
Cano
Open Access
Abstract: Renewed interest in covalent inhibitors of enzymes implicated in disease states has afforded several agents targeted at protein kinases of relevance to cancers. We now report the design, synthesis and biological evaluation of 6-ethynylpurines that act as covalent inhibitors of Nek2 by capturing a cysteine residue (Cys22) close to the catalytic domain of this protein kinase. Examination of the crystal structure of the non-covalent inhibitor 3-((6-cyclohexylmethoxy-7H-purin-2-yl)amino)benzamide in complex with Nek2 indicated that replacing the alkoxy with an ethynyl group places the terminus of the alkyne close to Cys22 and in a position compatible with the stereoelectronic requirements of a Michael addition. A series of 6-ethynylpurines was prepared and a structure activity relationship (SAR) established for inhibition of Nek2. 6-Ethynyl-N-phenyl-7H-purin-2-amine [IC50 0.15 μM (Nek2)] and 4-((6-ethynyl-7H-purin-2-yl)amino)benzenesulfonamide (IC50 0.14 μM) were selected for determination of the mode of inhibition of Nek2, which was shown to be time-dependent, not reversed by addition of ATP and negated by site directed mutagenesis of Cys22 to alanine. Replacement of the ethynyl group by ethyl or cyano abrogated activity. Variation of substituents on the N-phenyl moiety for 6-ethynylpurines gave further SAR data for Nek2 inhibition. The data showed little correlation of activity with the nature of the substituent, indicating that after sufficient initial competitive binding to Nek2 subsequent covalent modification of Cys22 occurs in all cases. A typical activity profile was that for 2-(3-((6-ethynyl-9H-purin-2-yl)amino)phenyl)acetamide [IC50 0.06 μM (Nek2); GI50 (SKBR3) 2.2 μM] which exhibited >5–10-fold selectivity for Nek2 over other kinases; it also showed > 50% growth inhibition at 10 μM concentration against selected breast and leukaemia cell lines. X-ray crystallographic analysis confirmed that binding of the compound to the Nek2 ATP-binding site resulted in covalent modification of Cys22. Further studies confirmed that 2-(3-((6-ethynyl-9H-purin-2-yl)amino)phenyl)acetamide has the attributes of a drug-like compound with good aqueous solubility, no inhibition of hERG at 25 μM and a good stability profile in human liver microsomes. It is concluded that 6-ethynylpurines are promising agents for cancer treatment by virtue of their selective inhibition of Nek2.
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May 2020
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I02-Macromolecular Crystallography
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Abstract: In silico virtual screening followed by in vitro biochemical, biophysical, and cellular screening resulted in the identification of distinctly different hTrkA kinase domain inhibitor scaffolds. X-ray structural analysis of representative inhibitors bound to hTrkA kinase domain defined the binding mode and rationalized the mechanism of action. Preliminary assessment of the sub-type selectivity against the closest hTrkB isoform, and early ADME guided the progression of select inhibitor leads in the screening cascade. The possibility of the actives sustaining to known hTrkA resistance mutations assessed in silico offers initial guidance into the required multiparametric lead optimization to arrive at a clinical candidate.
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Jan 2020
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