I03-Macromolecular Crystallography
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Isabelle B.
Pickles
,
Yurong
Chen
,
Olga
Moroz
,
Haley A.
Brown
,
Casper
De Boer
,
Zachary
Armstrong
,
Nicholas G. S.
Mcgregor
,
Marta
Artola
,
Jeroen D. C.
Codée
,
Nicole M.
Koropatkin
,
Herman S.
Overkleeft
,
Gideon J.
Davies
Diamond Proposal Number(s):
[24948, 32736]
Open Access
Abstract: α-Amylases are the workhorse enzymes of starch degradation. They are central to human health, including as targets for anti-diabetic compounds, but are also the key enzymes in the industrial processing of starch for biofuels, corn syrups, brewing and detergents. Dissection of the activity, specificity and stability of α-amylases is crucial to understanding their biology and allowing their exploitation. Yet, functional characterization lags behind DNA sequencing and genomics; and new tools are required for rapid analysis of α-amylase function. Here, we design, synthesize and apply new branched α-amylase activity-based probes. Using both α-1,6 branched and unbranched α-1,4 maltobiose activity-based probes we were able to explore the stability and substrate specificity of both a panel of human gut microbial α-amylases and a panel of industrially relevant α-amylases. We also demonstrate how we can detect and annotate the substrate specificity of α-amylases in the complex cell lysate of both a prominent gut microbe and a diverse compost sample by in-gel fluorescence and mass spectrometry. A toolbox of starch-active activity-based probes will enable rapid functional dissection of α-amylases. We envisage activity-based probes contributing to better selection and engineering of enzymes for industrial application as well as fundamental analysis of enzymes in human health.
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Nov 2024
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I03-Macromolecular Crystallography
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Valentina
Borlandelli
,
Wendy
Offen
,
Olga
Moroz
,
Alba
Nin-Hill
,
Nicholas
Mcgregor
,
Lars
Binkhorst
,
Akihiro
Ishiwata
,
Zachary
Armstrong
,
Marta
Artola
,
Carme
Rovira
,
Gideon J.
Davies
,
Herman S.
Overkleeft
Diamond Proposal Number(s):
[24948]
Open Access
Abstract: GH127 and GH146 microorganismal retaining β-l-arabinofuranosidases, expressed by human gut microbiomes, feature an atypical catalytic domain and an unusual mechanism of action. We recently reported that both Bacteroides thetaiotaomicron BtGH146 and Bifidobacterium longum HypBA1 are inhibited by β-l-arabinofuranosyl cyclophellitol epoxide, supporting the action of a zinc-coordinated cysteine as a catalytic nucleophile, where in most retaining GH families, an aspartate or glutamate is employed. This work presents a panel of β-l-arabinofuranosyl cyclophellitol epoxides and aziridines as mechanism-based BtGH146/HypBA1 inhibitors and activity-based probes. The β-l-arabinofuranosyl cyclophellitol aziridines both inhibit and label β-l-arabinofuranosidase efficiently (however with different activities), whereas the epoxide-derived probes favor BtGH146 over HypBA1. These findings are accompanied by X-ray structural analysis of the unmodified β-l-arabinofuranosyl cyclophellitol aziridine in complex with both isozymes, which were shown to react by nucleophilic opening of the aziridine, at the pseudoanomeric carbon, by the active site cysteine nucleophile to form a stable thioether bond. Altogether, our activity-based probes may serve as chemical tools for the detection and identification of low-abundance β-l-arabinofuranosidases in complex biological samples.
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Dec 2023
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I04-1-Macromolecular Crystallography (fixed wavelength)
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Diamond Proposal Number(s):
[24948, 18598]
Open Access
Abstract: Bacteria and yeasts grow on biomass polysaccharides by expressing and excreting a complex array of glycoside hydrolase (GH) enzymes. Identification and annotation of such GH pools, which are valuable commodities for sustainable energy and chemistries, by conventional means (genomics, proteomics) are complicated, as primary sequence or secondary structure alignment with known active enzymes is not always predictive for new ones. Here we report a “low-tech”, easy-to-use, and sensitive multiplexing activity-based protein-profiling platform to characterize the xyloglucan-degrading GH system excreted by the soil saprophyte, Cellvibrio japonicus, when grown on xyloglucan. A suite of activity-based probes bearing orthogonal fluorophores allows for the visualization of accessory exo-acting glycosidases, which are then identified using biotin-bearing probes. Substrate specificity of xyloglucanases is directly revealed by imbuing xyloglucan structural elements into bespoke activity-based probes. Our ABPP platform provides a highly useful tool to dissect xyloglucan-degrading systems from various sources and to rapidly select potentially useful ones. The observed specificity of the probes moreover bodes well for the study of other biomass polysaccharide-degrading systems, by modeling probe structures to those of desired substrates.
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Nov 2023
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I03-Macromolecular Crystallography
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Nicholas G. S.
Mcgregor
,
Chi-Lin
Kuo
,
Thomas
Beenakker
,
Chun-Sing
Wong
,
Wendy A.
Offen
,
Zachary
Armstrong
,
Bobby I.
Florea
,
Jeroen D.
Codee
,
Herman S.
Overkleeft
,
Hans
Aerts
,
Gideon
Davies
Diamond Proposal Number(s):
[24948, 18598]
Open Access
Abstract: Exo-β-mannosidases are a broad class of stereochemically retaining hydrolases that are essential for the breakdown of complex carbohydrate substrates found in all kingdoms of life. Yet the detection of exo-β-mannosidases in complex biological samples remains challenging, necessitating the development of new methodologies. Cyclophellitol and its analogues selectively label the catalytic nucleophiles of retaining glycoside hydrolases, making them valuable tool compounds. Furthermore, cyclophellitol can be readily redesigned to enable the incorporation of a detection tag, generating activity-based probes (ABPs) that can be used to detect and identify specific glycosidases in complex biological samples. Towards the development of ABPs for exo-β-mannosidases, we present a concise synthesis of β-manno-configured cyclophellitol, cyclophellitol aziridine, and N-alkyl cyclophellitol aziridines. We show that these probes covalently label exo-β-mannosidases from GH families 2, 5, and 164. Structural studies of the resulting complexes support a canonical mechanism-based mode of action in which the active site nucleophile attacks the pseudo-anomeric centre to form a stable ester linkage, mimicking the glycosyl enzyme intermediate. Furthermore, we demonstrate activity- based protein profiling using an N-alkyl aziridine derivative by specifically labelling MANBA in mouse kidney tissue. Together, these results show that synthetic manno-configured cyclophellitol analogues hold promise for detecting exo-β-mannosidases in biological and biomedical research.
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Dec 2021
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I03-Macromolecular Crystallography
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Nicholas G. S.
Mcgregor
,
Joan
Coines
,
Valentina
Borlandelli
,
Satoko
Amaki
,
Marta
Artola
,
Alba
Nin‐hill
,
Daniël
Linzel
,
Chihaya
Yamada
,
Takatoshi
Arakawa
,
Akihiro
Ishiwata
,
Yukishige
Ito
,
Gijsbert A.
Marel
,
Jeroen D. C.
Codée
,
Shinya
Fushinobu
,
Herman S.
Overkleeft
,
Carme
Rovira
,
Gideon J.
Davies
Diamond Proposal Number(s):
[18598]
Abstract: The recent discovery of zinc‐dependent retaining glycoside hydrolases (GHs), with active sites built around a Zn(Cys)3(Glu) coordination complex, has presented unresolved mechanistic questions. In particular, the proposed mechanism, depending on a Zn‐coordinated cysteine nucleophile and passing through a thioglycosyl enzyme intermediate, remains controversial. This is primarily due to the expected stability of the intermediate C−S bond. To facilitate the study of this atypical mechanism, we report the synthesis of a cyclophellitol‐derived β‐l‐arabinofuranosidase inhibitor, hypothesised to react with the catalytic nucleophile to form a non‐hydrolysable adduct analogous to the mechanistic covalent intermediate. This β‐l‐arabinofuranosidase inhibitor reacts exclusively with the proposed cysteine thiol catalytic nucleophiles of representatives of GH families 127 and 146. X‐ray crystal structures determined for the resulting adducts enable MD and QM/MM simulations, which provide insight into the mechanism of thioglycosyl enzyme intermediate breakdown. Leveraging the unique chemistry of cyclophellitol derivatives, the structures and simulations presented here support the assignment of a zinc‐coordinated cysteine as the catalytic nucleophile and illuminate the finely tuned energetics of this remarkable metalloenzyme clan.
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Feb 2021
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I03-Macromolecular Crystallography
I04-1-Macromolecular Crystallography (fixed wavelength)
I04-Macromolecular Crystallography
I23-Long wavelength MX
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Diamond Proposal Number(s):
[18598]
Open Access
Abstract: α-L-Arabinofuranosidases from glycoside hydrolase family 51 use a stereochemically retaining hydrolytic mechanism to liberate nonreducing terminal α-L-arabinofuranose residues from plant polysaccharides such as arabinoxylan and arabinan. To date, more than ten fungal GH51 α-L-arabinofuranosidases have been functionally characterized, yet no structure of a fungal GH51 enzyme has been solved. In contrast, seven bacterial GH51 enzyme structures, with low sequence similarity to the fungal GH51 enzymes, have been determined. Here, the crystallization and structural characterization of MgGH51, an industrially relevant GH51 α-L-arabinofuranosidase cloned from Meripilus giganteus, are reported. Three crystal forms were grown in different crystallization conditions. The unliganded structure was solved using sulfur SAD data collected from a single crystal using the I23 in vacuo diffraction beamline at Diamond Light Source. Crystal soaks with arabinose, 1,4-dideoxy-1,4-imino-L-arabinitol and two cyclophellitol-derived arabinose mimics reveal a conserved catalytic site and conformational itinerary between fungal and bacterial GH51 α-L-arabinofuranosidases.
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Nov 2020
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I03-Macromolecular Crystallography
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Casper
De Boer
,
Nicholas G. S.
Mcgregor
,
Evert
Peterse
,
Sybrin P.
Schröder
,
Bogdan I.
Florea
,
Jianbing
Jiang
,
Jos
Reijngoud
,
Arthur F. J.
Ram
,
Gilles P.
Van Wezel
,
Gijsbert A.
Van Der Marel
,
Jeroen D. C.
Codée
,
Herman S.
Overkleeft
,
Gideon
Davies
Diamond Proposal Number(s):
[18598]
Open Access
Abstract: Cellulases and related β-1,4-glucanases are essential components of lignocellulose-degrading enzyme mixtures. The detection of β-1,4-glucanase activity typically relies on monitoring the breakdown of purified lignocellulose-derived substrates or synthetic chromogenic substrates, limiting the activities which can be detected and complicating the tracing of activity back to specific components within complex enzyme mixtures. As a tool for the rapid detection and identification of β-1,4-glucanases, a series of glycosylated cyclophellitol inhibitors mimicking β-1,4-glucan oligosaccharides have been synthesised. These compounds are highly efficient inhibitors of HiCel7B, a well-known GH7 endo-β-1,4-glucanase. An elaborated activity-based probe facilitated the direct detection and identification of β-1,4-glucanases within a complex fungal secretome without any detectable cross-reactivity with β-D-glucosidases. These probes and inhibitors add valuable new capacity to the growing toolbox of cyclophellitol-derived probes for the activity-based profiling of biomass-degrading enzymes.
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Jul 2020
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I04-Macromolecular Crystallography
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Nicholas G. S.
Mcgregor
,
Marta
Artola
,
Alba
Nin-Hill
,
Daniel
Linzel
,
Mireille
Haon
,
Jos
Reijngoud
,
Arthur F. J.
Ram
,
Marie-Noelle
Rosso
,
Gijsbert A.
Van Der Marel
,
Jeroen D. C.
Codée
,
Gilles P.
Van Wezel
,
Jean-Guy
Berrin
,
Carme
Rovira
,
Herman S.
Overkleeft
,
Gideon J.
Davies
Diamond Proposal Number(s):
[18598]
Open Access
Abstract: Identifying and characterizing the enzymes responsible for an observed activity within a complex eukaryotic catabolic system remains one of the most significant challenges in the study of biomass-degrading systems. The debranching of both complex hemicellulosic and pectinaceous polysaccharides requires the production of α-L-arabinofuranosidases among a wide variety of co-expressed carbohydrate-active enzymes. To selectively detect and identify α-L-arabinofuranosidases produced by fungi grown on complex biomass, potential covalent inhibitors and probes which mimic α-L-arabinofuranosides were sought. The conformational free energy landscapes of free α-L-arabinofuranose and several rationally designed covalent α-L-arabinofuranosidase inhibitors were analyzed. A synthetic route to these inhibitors was subsequently developed based on a key Wittig-Still rearrangement. Through a combination of kinetic measurements, intact mass spectrometry, and structural experiments, the designed inhibitors were shown to efficiently label the catalytic nucleophiles of retaining GH51 and GH54 α-L-arabinofuranosidases. Activity-based probes elaborated from an inhibitor with an aziridine warhead were applied to the identification and characterization of α-L-arabinofuranosidases within the secretome of A. niger grown on arabinan. This method was extended to the detection and identification of α-L-arabinofuranosidases produced by eight biomass-degrading basidiomycete fungi grown on complex biomass. The broad applicability of the cyclophellitol-derived activity-based probes and inhibitors presented here make them a valuable new tool in the characterization of complex eukaryotic carbohydrate-degrading systems and in the high-throughput discovery of α-L-arabinofuranosidases.
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Feb 2020
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I03-Macromolecular Crystallography
I04-Macromolecular Crystallography
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Sybrin P.
Schröder
,
Casper
De Boer
,
Nicholas G. S.
Mcgregor
,
Rhianna J.
Rowland
,
Olga
Moroz
,
Elena
Blagova
,
Jos
Reijngoud
,
Mark
Arentshorst
,
David
Osborn
,
Marc D.
Morant
,
Eric
Abbate
,
Mary A.
Stringer
,
Kristian B. R. M.
Krogh
,
Lluís
Raich
,
Carme
Rovira
,
Jean-Guy
Berrin
,
Gilles P.
Van Wezel
,
Arthur F. J.
Ram
,
Bogdan I.
Florea
,
Gijsbert A.
Van Der Marel
,
Jeroen D. C.
Codée
,
Keith S.
Wilson
,
Liang
Wu
,
Gideon J.
Davies
,
Herman S.
Overkleeft
Diamond Proposal Number(s):
[13587]
Open Access
Abstract: Plant polysaccharides represent a virtually unlimited feedstock for the generation of biofuels and other commodities. However, the extraordinary recalcitrance of plant polysaccharides toward breakdown necessitates a continued search for enzymes that degrade these materials efficiently under defined conditions. Activity-based protein profiling provides a route for the functional discovery of such enzymes in complex mixtures and under industrially relevant conditions. Here, we show the detection and identification of β-xylosidases and endo-β-1,4-xylanases in the secretomes of Aspergillus niger, by the use of chemical probes inspired by the β-glucosidase inhibitor cyclophellitol. Furthermore, we demonstrate the use of these activity-based probes (ABPs) to assess enzyme–substrate specificities, thermal stabilities, and other biotechnologically relevant parameters. Our experiments highlight the utility of ABPs as promising tools for the discovery of relevant enzymes useful for biomass breakdown.
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May 2019
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I03-Macromolecular Crystallography
I04-1-Macromolecular Crystallography (fixed wavelength)
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Olga V.
Moroz
,
Pernille Foged
Jensen
,
Sean P
Mcdonald
,
Nicholas
Mcgregor
,
Elena
Blagova
,
Gerard
Comamala
,
Dorotea R.
Segura
,
Lars
Anderson
,
Santhosh M
Vasu
,
Vasudeva P
Rao
,
Lars
Giger
,
Trine Holst
Sørensen
,
Rune Nygaard
Monrad
,
Allan
Svendsen
,
Jens Erik
Nielsen
,
Bernard
Henrissat
,
Gideon
Davies
,
Harry
Brumer
,
Kasper D.
Rand
,
Keith S.
Wilson
Diamond Proposal Number(s):
[7864]
Abstract: The precise catalytic strategies used for the breakdown of the complex bacterial polysaccharide xanthan, an increasingly frequent component of processed human foodstuffs, have remained a mystery. Here we present the characterization of an endo-xanthanase from Paenibacillus sp. 62047. We show that it is a CAZy family 9 glycoside hydrolase (GH9) responsible for the hydrolysis of the xanthan backbone, capable of generating tetrameric xanthan oligosaccharides from polysaccharide lyase family 8 (PL8) xanthan lyase-treated xanthan. 3-D structure determination reveals a complex multi-modular enzyme in which a catalytic (α/α)6 barrel is flanked by an N-terminal "immunoglobulin-like" (Ig-like) domain (frequently found in GH9 enzymes) and by four additional C-terminal all β-sheet domains which have very few homologs in sequence databases and, at least, one of which functions as a new xanthan-binding domain, now termed CBM84. The solution phase conformation and dynamics of the enzyme in the native calcium-bound state and in the absence of calcium were probed experimentally by hydrogen/deuterium exchange mass spectrometry. Measured conformational dynamics were used to guide the protein engineering of enzyme variants with increased stability in the absence of calcium; a property of interest for the potential use of the enzyme in cleaning detergents. The ability of hydrogen/deuterium exchange mass spectrometry to pinpoint dynamic regions of a protein under stress (e.g. removal of calcium ions) makes this technology a strong tool for improving protein catalyst properties by informed engineering.
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May 2018
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