I02-Macromolecular Crystallography
I04-Macromolecular Crystallography
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Patrick
Weber
,
Martin
Thonhofer
,
Summer
Averill
,
Gideon J.
Davies
,
Andres Gonzalez
Santana
,
Philipp
Müller
,
Seyed A.
Nasseri
,
Wendy A.
Offen
,
Bettina M.
Pabst
,
Eduard
Paschke
,
Michael
Schalli
,
Ana
Torvisco
,
Marion
Tschernutter
,
Christina
Tysoe
,
Werner
Windischhofer
,
Stephen G.
Withers
,
Andreas
Wolfsgruber
,
Tanja M.
Wrodnigg
,
Arnold E.
Stütz
Open Access
Abstract: Glycosidase inhibitors have shown great potential as pharmacological chaperones for lysosomal storage diseases. In light of this, a series of new cyclopentanoid β-galactosidase inhibitors were prepared and their inhibitory and pharmacological chaperoning activities determined and compared with those of lipophilic analogs of the potent β-d-galactosidase inhibitor 4-epi-isofagomine. Structure-activity relationships were investigated by X-ray crystallography as well as by alterations in the cyclopentane moiety such as deoxygenation and replacement by fluorine of a “strategic” hydroxyl group. New compounds have revealed highly promising activities with a range of β-galactosidase-compromised human cell lines and may serve as leads towards new pharmacological chaperones for GM1-gangliosidosis and Morquio B disease.
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Sep 2020
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I04-1-Macromolecular Crystallography (fixed wavelength)
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Tessa
Keenan
,
Fabio
Parmeggiani
,
Julien
Malassis
,
Clement Q.
Fontenelle
,
Jean-baptiste
Vendeville
,
Wendy
Offen
,
Peter
Both
,
Kun
Huang
,
Andrea
Marchesi
,
Alex
Heyam
,
Carl
Young
,
Simon J.
Charnock
,
Gideon J.
Davies
,
Bruno
Linclau
,
Sabine L.
Flitsch
,
Martin A.
Fascione
Diamond Proposal Number(s):
[13587, 18598]
Abstract: Fluorinated sugar-1-phosphates are of emerging importance as intermediates in the chemical and biocatalytic synthesis of modified oligosaccharides, as well as probes for chemical biology. Here we present a systematic study of the activity of a wide range of anomeric sugar kinases (galacto- and N-acetylhexosamine kinases) against a panel of fluorinated monosaccharides, leading to the first examples of polyfluorinated substrates accepted by this class of enzymes. We have discovered four new N-acetylhexosamine kinases with a different substrate scope, thus expanding the number of homologs available in this subclass of kinases. Lastly, we have solved the crystal structure of a galactokinase in complex with 2-deoxy-2-fluorogalactose, giving insight into changes in the active site that may account for the specificity of the enzyme toward certain substrate analogs.
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Jul 2020
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I04-1-Macromolecular Crystallography (fixed wavelength)
I04-Macromolecular Crystallography
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Diamond Proposal Number(s):
[13587, 18598]
Abstract: Alternatives to petroleum-based chemicals are highly sought-after for on-going efforts to reduce the damaging effects of human activity on the environment. Copper radical oxidases from Auxiliary Activity Family 5/Subfamily 2 (AA5_2) are attractive biocatalysts because they oxidize primary alcohols in a chemo-selective manner without complex organic cofactors. However, despite numerous studies on canonical galactose oxidases (GalOx, EC 1.1.3.9) and engineered variants, and the recent discovery of a Colletotrichum graminicola copper radical alcohol oxidase (AlcOx, EC 1.1.3.13), the catalytic potentials of very few AA5_2 members have been characterized. Guided by sequence similarity network and phylogenetic analyses, in this study we targeted a distinct paralog from the fungus C. graminicola as a representative member of a large uncharacterized subgroup of AA5_2. Through recombinant production and detailed kinetic analysis, we demonstrated that this enzyme is weakly active towards carbohydrates, but efficiently catalyzes the oxidation of aryl alcohols to the corresponding aldehydes. As such, this represents the initial characterization of a demonstrable aryl alcohol oxidase (AAO, EC 1.1.3.7) in AA5, an activity which is classically associated with flavin-dependent glucose-methanol-choline (GMC) oxidoreductases of Auxiliary Activity Family 3 (AA3). X-ray crystallography revealed a distinct multidomain architecture comprising an N-terminal PAN domain abutting a canonical AA5 seven-bladed propeller catalytic domain. Of direct relevance to biomass processing, the wild-type enzyme exhibits the highest activity on the primary alcohol of 5-hydroxymethylfurfural (HMF), a product of significant interest in the lignocellulosic bio-refinery concept. Thus, the chemoselective oxidation of HMF to 2,5-diformylfuran (DFF) by C. graminicola aryl alcohol oxidase (CgrAAO) from AA5 provides a fundamental building block for chemistry via biotechnology.
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Feb 2020
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I02-Macromolecular Crystallography
I03-Macromolecular Crystallography
I04-1-Macromolecular Crystallography (fixed wavelength)
I04-Macromolecular Crystallography
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Diamond Proposal Number(s):
[7864, 9948]
Abstract: The opium poppy, Papaver somniferum, has been a source of medicinal alkaloids since the earliest civilizations; ca. 3400 B.C. The benzylisoquinoline alkaloid noscapine is produced commercially in P. somniferum for use as a cough suppressant and it also has potential as an anticancer compound. The first committed step in the recently elucidated noscapine biosynthetic pathway involves the conversion of scoulerine to tetrahydrocolumbamine by 9-O-methylation, catalysed by O-methyltransferase 1 (PSMT1). We demonstrate, through protein structures (obtained through rational crystal engineering at resolutions from 1.5 to 1.2Å for the engineered variants) across the reaction coordinate, how domain closure allows specific methyl transfer to generate the product. SAM-dependent methyl transfer is central to myriad natural products in plants, analysis of amino-acid sequence, now taking the three-dimensional structure of PSMT1 and low identity homologs into account, begins to shed light on the structural features that govern substrate specificity in these key, ubiquitous, plant enzymes. We propose how “gatekeeper” residues can determine acceptor regiochemistry thus allowing prediction across the wide genomic resource.
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Mar 2019
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I03-Macromolecular Crystallography
I04-1-Macromolecular Crystallography (fixed wavelength)
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Diamond Proposal Number(s):
[13587]
Abstract: Xyloglucan (XyG) is a complex polysaccharide that is ubiquitous and often abundant in the cell walls of terrestrial plants. XyG metabolism is therefore a key component of the global carbon cycle, and hence XyG enzymology is of significant fundamental and applied importance in biomass conversion. To facilitate structure–function analyses of XyG-specific endo-glucanases, we have synthesized a 2′,4′-dinitrophenyl 2-deoxy-2-fluoro-β-glycoside mechanism-based inhibitor based on the highly branched XyG repeating motif XXXG (Xyl3Glc4: ([α-D-Xylp-(1→6)]-β-D-Glcp-(1→4)-[α-D-Xylp-(1→6)]-β-D-Glcp-(1→4)-[α-D-Xylp-(1→6)]-β-D-Glcp-(1→4)-D-Glcp. Key steps in the chemo-enzymatic synthesis included selective enzyme hydrolysis of XyG polysaccharide to produce the core heptasaccharide, per-O-acetylation, α-bromination, reductive glycal formation, electrophilic fluorination, SNAr glycosylation, and Zemplen deprotection. The resulting compound, XXXG(2F)-β-DNP, specifically labelled the active sites of several endo-(xylo)glucanases by accumulation of a covalent glycosyl-enzyme intermediate, as revealed by intact protein mass spectrometry. Crystallography of a complex with a Cellvibrio japonicus Glycoside Hydrolase Family 5 (GH5) endo-xyloglucanase corroborated the covalent nature of the intermediate, and further revealed the anticipated specificity for the catalytic nucleophile of this anomeric-configuration-retaining glycosidase. This specificity complements that of an analogous XXXG N-bromoacetylglycosylamine inhibitor, which labelled the catalytic acid–base sidechain in the same enzyme [Attia, et al., Biotechnol. Biofuels, 2018, 11, 45]. We anticipate that these inhibitors may find continued use in mechanistic analyses of endo-(xylo)glucanases from diverse GH families.
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Oct 2018
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I03-Macromolecular Crystallography
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Sybrin P.
Schröder
,
Liang
Wu
,
Marta
Artola
,
Thomas
Hansen
,
Wendy A.
Offen
,
Maria J.
Ferraz
,
Kah-yee
Li
,
Johannes M. F. G.
Aerts
,
Gijsbert A.
Van Der Marel
,
Jeroen D. C.
Codée
,
Gideon J.
Davies
,
Herman S.
Overkleeft
Diamond Proposal Number(s):
[13587]
Abstract: Gluco-azoles competitively inhibit glucosidases by transition-state mimicry and their ability to interact with catalytic acid residues in glucosidase active sites. We noted that no azole-type inhibitors described, to date, possess a protic nitrogen characteristic for 1H-imidazoles. Here, we present gluco-1H-imidazole, a gluco-azole bearing a 1H-imidazole fused to a glucopyranose-configured cyclitol core, and three close analogues as new glucosidase inhibitors. All compounds inhibit human retaining β-glucosidase, GBA1, with the most potent ones inhibiting this enzyme (deficient in Gaucher disease) on a par with glucoimidazole. None inhibit glucosylceramide synthase, cytosolic β-glucosidase GBA2 or α-glucosidase GAA. Structural, physical and computational studies provide first insights into the binding mode of this conceptually new class of retaining β-glucosidase inhibitors.
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Mar 2018
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I03-Macromolecular Crystallography
I04-Macromolecular Crystallography
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Diamond Proposal Number(s):
[9948]
Open Access
Abstract: Background:
Xyloglucan (XyG) is a ubiquitous and fundamental polysaccharide of plant cell walls. Due to its structural complexity, XyG requires a combination of backbone-cleaving and sidechain-debranching enzymes for complete deconstruction into its component monosaccharides. The soil saprophyte Cellvibrio japonicus has emerged as a genetically tractable model system to study biomass saccharification, in part due to its innate capacity to utilize a wide range of plant polysaccharides for growth. Whereas the downstream debranching enzymes of the xyloglucan utilization system of C. japonicus have been functionally characterized, the requisite backbone-cleaving endo-xyloglucanases were unresolved.
Results:
Combined bioinformatic and transcriptomic analyses implicated three glycoside hydrolase family 5 subfamily 4 (GH5_4) members, with distinct modular organization, as potential keystone endo-xyloglucanases in C. japonicus. Detailed biochemical and enzymatic characterization of the GH5_4 modules of all three recombinant proteins confirmed particularly high specificities for the XyG polysaccharide versus a panel of other cell wall glycans, including mixed-linkage beta-glucan and cellulose. Moreover, product analysis demonstrated that all three enzymes generated XyG oligosaccharides required for subsequent saccharification by known exo-glycosidases. Crystallographic analysis of GH5D, which was the only GH5_4 member specifically and highly upregulated during growth on XyG, in free, product-complex, and active-site affinity-labelled forms revealed the molecular basis for the exquisite XyG specificity among these GH5_4 enzymes. Strikingly, exhaustive reverse-genetic analysis of all three GH5_4 members and a previously biochemically characterized GH74 member failed to reveal a growth defect, thereby indicating functional compensation in vivo, both among members of this cohort and by other, yet unidentified, xyloglucanases in C. japonicus. Our systems-based analysis indicates distinct substrate-sensing (GH74, GH5E, GH5F) and attack-mounting (GH5D) functions for the endo-xyloglucanases characterized here.
Conclusions:
Through a multi-faceted, molecular systems-based approach, this study provides a new insight into the saccharification pathway of xyloglucan utilization system of C. japonicus. The detailed structural–functional characterization of three distinct GH5_4 endo-xyloglucanases will inform future bioinformatic predictions across species, and provides new CAZymes with defined specificity that may be harnessed in industrial and other biotechnological applications.
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Feb 2018
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I02-Macromolecular Crystallography
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Sybrin P.
Schröder
,
Jasper W.
Van De Sande
,
Wouter W.
Kallemeijn
,
Chi-lin
Kuo
,
Marta
Artola
,
Eva J.
Van Rooden
,
Jianbing
Jiang
,
Thomas J. M.
Beenakker
,
Bogdan I.
Florea
,
Wendy
Offen
,
Gideon
Davies
,
Adriaan J.
Minnaard
,
Johannes M. F. G.
Aerts
,
Jeroen D. C.
Codée
,
Gijsbert A.
Van Der Marel
,
Herman S.
Overkleeft
Diamond Proposal Number(s):
[9948]
Open Access
Abstract: Activity-based protein profiling has emerged as a powerful tool for visualizing glycosidases in complex biological samples. Several configurational cyclophellitol isomers have been shown to display high selectivity as probes for glycosidases processing substrates featuring the same configuration. Here, a set of deoxygenated cyclophellitols are presented which enable inter-class profiling of β-glucosidases and β-galactosidases.
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Nov 2017
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I02-Macromolecular Crystallography
I04-Macromolecular Crystallography
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Marta
Artola
,
Liang
Wu
,
Maria J.
Ferraz
,
Chi-lin
Kuo
,
Lluís
Raich
,
Imogen Z.
Breen
,
Wendy A.
Offen
,
Jeroen D. C.
Codée
,
Gijsbert A.
Van Der Marel
,
Carme
Rovira
,
Johannes M. F. G.
Aerts
,
Gideon J.
Davies
,
Herman S.
Overkleeft
Diamond Proposal Number(s):
[13587]
Open Access
Abstract: The essential biological roles played by glycosidases, coupled to the diverse therapeutic benefits of pharmacologically targeting these enzymes, provide considerable motivation for the development of new inhibitor classes. Cyclophellitol epoxides and aziridines are recently established covalent glycosidase inactivators. Inspired by the application of cyclic sulfates as electrophilic equivalents of epoxides in organic synthesis, we sought to test whether cyclophellitol cyclosulfates would similarly act as irreversible glycosidase inhibitors. Here we present the synthesis, conformational analysis, and application of novel 1,6-cyclophellitol cyclosulfates. We show that 1,6-epi-cyclophellitol cyclosulfate (α-cyclosulfate) is a rapidly reacting α-glucosidase inhibitor whose 4C1 chair conformation matches that adopted by α-glucosidase Michaelis complexes. The 1,6-cyclophellitol cyclosulfate (β-cyclosulfate) reacts more slowly, likely reflecting its conformational restrictions. Selective glycosidase inhibitors are invaluable as mechanistic probes and therapeutic agents, and we propose cyclophellitol cyclosulfates as a valuable new class of carbohydrate mimetics for application in these directions.
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Jul 2017
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I02-Macromolecular Crystallography
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Thomas J. M.
Beenakker
,
Dennis P. A.
Wander
,
Wendy
Offen
,
Marta
Artola
,
Lluís
Raich
,
Maria J.
Ferraz
,
Kah-yee
Li
,
Judith H. P. M.
Houben
,
Erwin R.
Van Rijssel
,
Thomas
Hansen
,
Gijsbert A.
Van Der Marel
,
Jeroen D. C.
Codée
,
Johannes M. F. G.
Aerts
,
Carme
Rovira
,
Gideon J.
Davies
,
Herman S.
Overkleeft
Diamond Proposal Number(s):
[13587]
Abstract: The conformational analysis of glycosidases affords a route to their specific inhibition through transition-state mimicry. Inspired by the rapid reaction rates of cyclophellitol and cyclophellitol aziridine—both covalent retaining β-glucosidase inhibitors—we postulated that the corresponding carba “cyclopropyl” analogue would be a potent retaining β-glucosidase inhibitor for those enzymes reacting through the 4H3 transition-state conformation. Ab initio metadynamics simulations of the conformational free energy landscape for the cyclopropyl inhibitors show a strong bias for the 4H3 conformation, and carba-cyclophellitol, with an N-(4-azidobutyl)carboxamide moiety, proved to be a potent inhibitor (Ki = 8.2 nM) of the Thermotoga maritima TmGH1 β-glucosidase. 3-D structural analysis and comparison with unreacted epoxides show that this compound indeed binds in the 4H3 conformation, suggesting that conformational strain induced through a cyclopropyl unit may add to the armory of tight-binding inhibitor designs.
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May 2017
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