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Article ; Online: The neutron Electric Dipole Moment experiment at the Paul Scherrer Institute

Hélaine V.

EPJ Web of Conferences, Vol 73, p

2014 Volume 07003

Abstract: The neutron Electric Dipole Moment (nEDM) is a probe for physics beyond the Standard Model. A report on the nEDM measurement performed at the Paul Scherrer Institute (Switzerland) is given. A neutron spin analyzer designed to simultaneously detect both ... ...

Abstract	The neutron Electric Dipole Moment (nEDM) is a probe for physics beyond the Standard Model. A report on the nEDM measurement performed at the Paul Scherrer Institute (Switzerland) is given. A neutron spin analyzer designed to simultaneously detect both neutron spin states is presented.
Keywords	Physics ; QC1-999 ; Science ; Q
Language	English
Publishing date	2014-06-01T00:00:00Z
Publisher	EDP Sciences
Document type	Article ; Online
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Article ; Online: Insights into the Thiamine Diphosphate Enzyme Activation Mechanism: Computational Model for Transketolase Using a Quantum Mechanical/Molecular Mechanical Method.

Nauton, Lionel / Hélaine, Virgil / Théry, Vincent / Hecquet, Laurence

Biochemistry

2016 Volume 55, Issue 14, Page(s) 2144–2152

Abstract: We propose the first computational model for transketolase (TK), a thiamine diphosphate (ThDP)-dependent enzyme, using a quantum mechanical/molecular mechanical method on the basis of crystallographic TK structures from yeast and Escherichia coli, ... ...

Abstract	We propose the first computational model for transketolase (TK), a thiamine diphosphate (ThDP)-dependent enzyme, using a quantum mechanical/molecular mechanical method on the basis of crystallographic TK structures from yeast and Escherichia coli, together with experimental kinetic data reported in the literature with wild-type and mutant TK. This model allowed us to define a new route for ThDP activation in the enzyme environment. We evidenced a strong interaction between ThDP and Glu418B of the TK active site, itself stabilized by Glu162A. The crucial point highlighted here is that deprotonation of ThDP C2 is not performed by ThDP N4' as reported in the literature, but by His481B, involving a HOH688A molecule bridge. Thus, ThDP N4' is converted from an amino form to an iminium form, ensuring the stabilization of the C2 carbanion or carbene. Finally, ThDP activation proceeds via an intermolecular process and not by an intramolecular one as reported in the literature. More generally, this proposed ThDP activation mechanism can be applied to some other ThDP-dependent enzymes and used to define the entire TK mechanism with donor and acceptor substrates more accurately.
MeSH term(s)	Amino Acid Substitution ; Binding Sites ; Biocatalysis ; Catalytic Domain ; Computational Biology ; Databases, Protein ; Dimerization ; Energy Transfer ; Enzyme Activation ; Escherichia coli Proteins/chemistry ; Escherichia coli Proteins/genetics ; Escherichia coli Proteins/metabolism ; Models, Molecular ; Molecular Conformation ; Molecular Dynamics Simulation ; Mutation ; Quantum Theory ; Saccharomyces cerevisiae Proteins/chemistry ; Saccharomyces cerevisiae Proteins/genetics ; Saccharomyces cerevisiae Proteins/metabolism ; Structural Homology, Protein ; Thermodynamics ; Thiamine Pyrophosphate/chemistry ; Thiamine Pyrophosphate/metabolism ; Transketolase/chemistry ; Transketolase/genetics ; Transketolase/metabolism ; Vitamin B Complex/chemistry ; Vitamin B Complex/metabolism
Chemical Substances	Escherichia coli Proteins ; Saccharomyces cerevisiae Proteins ; Vitamin B Complex (12001-76-2) ; TKL1 protein, S cerevisiae (EC 2.2.1.1) ; Transketolase (EC 2.2.1.1) ; Thiamine Pyrophosphate (Q57971654Y)
Language	English
Publishing date	2016-04-12
Publishing country	United States
Document type	Journal Article
ZDB-ID	1108-3
ISSN	1520-4995 ; 0006-2960
ISSN (online)	1520-4995
ISSN	0006-2960
DOI	10.1021/acs.biochem.5b00787
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Article ; Online: Fluorogenic substrates for the screening assay of transketolase through beta-elimination of umbelliferone--Development, scope and limitations.

Charmantray, F / Légeret, B / Hélaine, V / Hecquet, L

Journal of biotechnology

2010 Volume 145, Issue 4, Page(s) 359–366

Abstract: 5-O-Coumarinyl-d-xylulose was studied as a fluorogenic substrate for the stereospecific assay of transketolase enzyme. Enzymatic C2-C3 cleavage released an alpha-hydroxyl, beta-coumarinyl substituted aldehyde. Although the subsequent beta-elimination ... ...

Abstract	5-O-Coumarinyl-d-xylulose was studied as a fluorogenic substrate for the stereospecific assay of transketolase enzyme. Enzymatic C2-C3 cleavage released an alpha-hydroxyl, beta-coumarinyl substituted aldehyde. Although the subsequent beta-elimination step was rate limiting under chemical or enzymatic catalysis, we detected a TK activity as low as 0.7mIU. To improve the fluorescence signal release, kinetic and product distribution analyses of this reaction were performed by LC/UV/MS coupling.
MeSH term(s)	Animals ; Cattle ; Chromatography, Liquid ; Enzyme Assays/methods ; Fluorescent Dyes/chemistry ; Fluorescent Dyes/metabolism ; Kinetics ; Limit of Detection ; Mass Spectrometry ; Saccharomyces cerevisiae/enzymology ; Serum Albumin, Bovine/metabolism ; Stereoisomerism ; Transaldolase/metabolism ; Transketolase/metabolism ; Umbelliferones/chemistry ; Umbelliferones/metabolism
Chemical Substances	Fluorescent Dyes ; Umbelliferones ; Serum Albumin, Bovine (27432CM55Q) ; 7-hydroxycoumarin (60Z60NTL4G) ; Transketolase (EC 2.2.1.1) ; Transaldolase (EC 2.2.1.2)
Language	English
Publishing date	2010-02-15
Publishing country	Netherlands
Document type	Journal Article
ZDB-ID	843647-2
ISSN	1873-4863 ; 0168-1656 ; 1389-0352
ISSN (online)	1873-4863
ISSN	0168-1656 ; 1389-0352
DOI	10.1016/j.jbiotec.2009.12.022
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Article: Biocatalytic synthesis of hydroxylated natural products using aldolases and related enzymes.

Fessner, W D / Helaine, V

Current opinion in biotechnology

2001 Volume 12, Issue 6, Page(s) 574–586

Abstract: Synthetic building blocks bearing hydroxylated chiral centers are important targets for biocatalysis. Many C-C bond forming enzymes have recently been investigated for new applications and new strategies towards the synthesis of natural products and ... ...

Abstract	Synthetic building blocks bearing hydroxylated chiral centers are important targets for biocatalysis. Many C-C bond forming enzymes have recently been investigated for new applications and new strategies towards the synthesis of natural products and related oxygenated compounds. Several old catalysts have been studied to increase our functional knowledge of natural aldolase-type enzymes, and new mutated catalysts or catalytic antibodies have been tested for their synthetic utility.
MeSH term(s)	Aldehyde-Lyases/chemistry ; Amino Acids/chemistry ; Biotechnology/methods ; Carbon/chemistry ; Catalysis ; Hydroxylation ; Models, Chemical ; Transketolase/chemistry
Chemical Substances	Amino Acids ; Carbon (7440-44-0) ; Transketolase (EC 2.2.1.1) ; Aldehyde-Lyases (EC 4.1.2.-) ; mandelonitrile lyase (EC 4.1.2.10)
Language	English
Publishing date	2001-12
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't ; Review
ZDB-ID	1052045-4
ISSN	1879-0429 ; 0958-1669
ISSN (online)	1879-0429
ISSN	0958-1669
DOI	10.1016/s0958-1669(01)00265-8
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Article ; Online: 2-Ketogluconate Kinase from

Sánchez-Moreno, Israel / Trachtmann, Natalia / Ilhan, Sibel / Hélaine, Virgil / Lemaire, Marielle / Guérard-Hélaine, Christine / Sprenger, Georg A

Molecules (Basel, Switzerland)

2019 Volume 24, Issue 13

Abstract: We have cloned, overexpressed, purified, and characterized a 2-ketogluconate kinase (2-dehydrogluconokinase, EC 2.7.1.13) ... ...

Abstract	We have cloned, overexpressed, purified, and characterized a 2-ketogluconate kinase (2-dehydrogluconokinase, EC 2.7.1.13) from
MeSH term(s)	Bacterial Proteins/chemistry ; Bacterial Proteins/genetics ; Bacterial Proteins/metabolism ; Cloning, Molecular ; Cupriavidus necator/enzymology ; Gluconates/metabolism ; Phosphorylation ; Protein Kinases/chemistry ; Protein Kinases/genetics ; Protein Kinases/metabolism ; Protein Stability ; Substrate Specificity
Chemical Substances	Bacterial Proteins ; Gluconates ; 2-ketogluconate (20248-27-5) ; Protein Kinases (EC 2.7.-)
Language	English
Publishing date	2019-06-28
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	1413402-0
ISSN	1420-3049 ; 1431-5165 ; 1420-3049
ISSN (online)	1420-3049
ISSN	1431-5165 ; 1420-3049
DOI	10.3390/molecules24132393
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Article ; Online: An efficient amperometric transketolase assay: towards inhibitor screening.

Touisni, Nadia / Charmantray, Franck / Hélaine, Virgil / Hecquet, Laurence / Mousty, Christine

Biosensors & bioelectronics

2014 Volume 62, Page(s) 90–96

Abstract: This paper describes an innovative amperometric biosensor for the in vitro determination of activity of transketolase from Escherichia coli (TKec) using commercially available TK substrates, namely d-fructose-6-phosphate a physiological donor and ... ...

Abstract	This paper describes an innovative amperometric biosensor for the in vitro determination of activity of transketolase from Escherichia coli (TKec) using commercially available TK substrates, namely d-fructose-6-phosphate a physiological donor and glycolaldehyde the best non-phosphorylated acceptor. A galactose oxidase (GAOx) biosensor, based on the immobilization of this enzyme within laponite clay, allows amperometric detection of L-erythrulose released upon TK-catalyzed reaction. A calibration curve has been established from 0.01 to 0.1 U ml(-1) TKec concentration in solution. These data are comparable to that obtained by a fluorometric method. In order to ensure a higher sensitivity and re-usability of the system, an original bienzymatic sensing system was further developed based on apoenzyme TKec and GAOx separately immobilized on the electrode surface. The inner sensing layer contains GAOx@laponite and the outer layer TKec@layered double hydroxide biohybrid. The biosensor response was validated by the determination of KD(app) for thiamine diphosphate, the TK cofactor and the inhibition action of two commercially available products, pyrophosphate, a TK cofactor analog and d-arabinose-5-phosphate, a substrate analog.
MeSH term(s)	Ascomycota/enzymology ; Biosensing Techniques/instrumentation ; Electrochemical Techniques/instrumentation ; Enzyme Assays/instrumentation ; Enzyme Inhibitors/pharmacology ; Enzymes, Immobilized/metabolism ; Equipment Design ; Escherichia coli/enzymology ; Galactose Oxidase/metabolism ; Silicates/chemistry ; Transketolase/antagonists & inhibitors ; Transketolase/metabolism
Chemical Substances	Enzyme Inhibitors ; Enzymes, Immobilized ; Silicates ; laponite (D703131383) ; Galactose Oxidase (EC 1.1.3.9) ; Transketolase (EC 2.2.1.1)
Language	English
Publishing date	2014-12-15
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	1011023-9
ISSN	1873-4235 ; 0956-5663
ISSN (online)	1873-4235
ISSN	0956-5663
DOI	10.1016/j.bios.2014.06.019
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Article: Efficient biocatalytic processes for highly valuable terminally phosphorylated C5 to C9 d-ketoses

Guérard-Hélaine, C / Clapés, P / Debacker, M / Hélaine, V / Lemaire, M / Szekrenyi, A

Green chemistry. 2014 Feb. 24, v. 16, no. 3

2014

Abstract: A green enzymatic strategy for the synthesis of terminally phosphorylated C5 to C9 naturally occurring d-ketose phosphates and analogues was developed using d-fructose-6-phosphate aldolase (FSA) as a catalyst. This enzyme has stereoselectively catalysed ... ...

Abstract	A green enzymatic strategy for the synthesis of terminally phosphorylated C5 to C9 naturally occurring d-ketose phosphates and analogues was developed using d-fructose-6-phosphate aldolase (FSA) as a catalyst. This enzyme has stereoselectively catalysed aldol reactions between glycolaldehyde phosphate or ribose-5-phosphate as an acceptor substrate and dihydroxyacetone, hydroxyacetone or hydroxybutanone as a donor. Furthermore, d-glycero-d-altro-2-octulose 8-phosphate was obtained using a straightforward one-pot domino biocatalytic system involving FSA, ribulose-5-phosphate epimerase and ribose-5-phosphate isomerase controlling five contiguous asymmetric centres and starting from achiral material.
Keywords	biocatalysis ; catalysts ; fructose-bisphosphate aldolase ; green chemistry ; isomerases ; phosphates ; stereoselectivity
Language	English
Dates of publication	2014-0224
Size	p. 1109-1113.
Publishing place	The Royal Society of Chemistry
Document type	Article
ZDB-ID	2006274-6
ISSN	1463-9270 ; 1463-9262
ISSN (online)	1463-9270
ISSN	1463-9262
DOI	10.1039/c3gc42140f
Database	NAL-Catalogue (AGRICOLA)

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Article: Fluorogenic substrates for the screening assay of transketolase through beta-elimination of umbelliferone—Development, scope and limitations

Charmantray, F / Légeret, B / Hélaine, V / Hecquet, L

Journal of biotechnology. 2010 Feb. 15, v. 145, no. 4

2010

Abstract: 5-O-Coumarinyl-d-xylulose was studied as a fluorogenic substrate for the stereospecific assay of transketolase enzyme. Enzymatic C2-C3 cleavage released an α-hydroxyl, β-coumarinyl substituted aldehyde. Although the subsequent β-elimination step was rate ...

Abstract	5-O-Coumarinyl-d-xylulose was studied as a fluorogenic substrate for the stereospecific assay of transketolase enzyme. Enzymatic C2-C3 cleavage released an α-hydroxyl, β-coumarinyl substituted aldehyde. Although the subsequent β-elimination step was rate limiting under chemical or enzymatic catalysis, we detected a TK activity as low as 0.7mIU. To improve the fluorescence signal release, kinetic and product distribution analyses of this reaction were performed by LC/UV/MS coupling.
Keywords	biotechnology ; catalytic activity ; fluorescence ; screening ; transketolase
Language	English
Size	p. 359-366.
Publishing place	Elsevier
Document type	Article
ZDB-ID	843647-2
ISSN	1873-4863 ; 0168-1656 ; 1389-0352
ISSN (online)	1873-4863
ISSN	0168-1656 ; 1389-0352
DOI	10.1016/j.jbiotec.2009.12.022
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Article ; Online: 2-Deoxyribose-5-phosphate aldolase, a remarkably tolerant aldolase towards nucleophile substrates.

Chambre, Domitille / Guérard-Hélaine, Christine / Darii, Ekaterina / Mariage, Aline / Petit, Jean-Louis / Salanoubat, Marcel / de Berardinis, Véronique / Lemaire, Marielle / Hélaine, Virgil

Chemical communications (Cambridge, England)

2019 Volume 55, Issue 52, Page(s) 7498–7501

Abstract: We explored a collection of 2-deoxyribose-5-phosphate aldolases (DERAs) from biodiversity for their nucleophile substrate promiscuity. The DERAs were screened using as nucleophiles propanone, propanal, cyclobutanone, cyclopentanone, dihydroxyacetone, and ...

Abstract	We explored a collection of 2-deoxyribose-5-phosphate aldolases (DERAs) from biodiversity for their nucleophile substrate promiscuity. The DERAs were screened using as nucleophiles propanone, propanal, cyclobutanone, cyclopentanone, dihydroxyacetone, and glycolaldehyde with l-glyceraldehyde-3-phosphate as an electrophile in aldol addition. A DERA from Arthrobacter chlorophenolicus (DERA
MeSH term(s)	Aldehyde-Lyases/genetics ; Aldehyde-Lyases/metabolism ; Aldehydes/chemistry ; Aldehydes/metabolism ; Arthrobacter/enzymology ; Bacterial Proteins/genetics ; Bacterial Proteins/metabolism ; Biocatalysis ; Biodiversity ; Escherichia coli/enzymology ; Glyceraldehyde 3-Phosphate/metabolism ; Substrate Specificity
Chemical Substances	Aldehydes ; Bacterial Proteins ; Glyceraldehyde 3-Phosphate (142-10-9) ; 3-hydroxybutanal (8C6G962B53) ; Aldehyde-Lyases (EC 4.1.2.-)
Language	English
Publishing date	2019-06-12
Publishing country	England
Document type	Journal Article
ZDB-ID	1472881-3
ISSN	1364-548X ; 1359-7345 ; 0009-241X
ISSN (online)	1364-548X
ISSN	1359-7345 ; 0009-241X
DOI	10.1039/c9cc03361k
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Article ; Online: Optimized immobilization of transketolase from E. coli in MgAl-layered double hydroxides.

Touisni, Nadia / Charmantray, Franck / Helaine, Virgil / Forano, Claude / Hecquet, Laurence / Mousty, Christine

Colloids and surfaces. B, Biointerfaces

2013 Volume 112, Page(s) 452–459

Abstract: Immobilization of TK from Escherichia coli (TKec) on MgAl-NO3 layered double hydroxides (LDH) was carried out by two processes: adsorption and coprecipitation. As a comparison, the adsorption method was realized either at pH 7.5 in buffered solutions ( ... ...

Abstract	Immobilization of TK from Escherichia coli (TKec) on MgAl-NO3 layered double hydroxides (LDH) was carried out by two processes: adsorption and coprecipitation. As a comparison, the adsorption method was realized either at pH 7.5 in buffered solutions (MOPS and Gly-Gly) or in pure water. For the coprecipitation method, the formation of the inorganic LDH support was realized directly in the presence of TKec solubilized in Gly-Gly. The prepared biohybrids, called respectively TKec@LDHads and TKec@LDHcop, were characterized by powder X-ray diffraction, FTIR spectroscopy in comparison with TKec free reference products, i.e. MgAl-NO3, MgAl-Gly-Gly. The enzymatic activities of the various TKec@LDH biohybrids as well as their stabilities over time were investigated by UV-vis assay. A maximum of activity (12 U/mg of solid) was reached for TKec@MgAl-Gly-Gly biohybrid prepared by coprecipitation. Finally, thin films were prepared through a one-step deposition on a polished support. The enzymatic activity of the resulting TKec@MgAl-Gly-Glycop film was tested over four recycling processes with a reproducible activity of 2.7 U/mg cm(2).
MeSH term(s)	Adsorption ; Aluminum Hydroxide/chemistry ; Biocatalysis ; Biosensing Techniques/methods ; Chemical Precipitation ; Drug Combinations ; Enzyme Stability ; Enzymes, Immobilized/metabolism ; Escherichia coli/enzymology ; Escherichia coli Proteins/metabolism ; Magnesium Hydroxide/chemistry ; Powder Diffraction ; Spectroscopy, Fourier Transform Infrared ; Surface Properties ; Transketolase/metabolism
Chemical Substances	Drug Combinations ; Enzymes, Immobilized ; Escherichia coli Proteins ; aluminum hydroxide, magnesium hydroxide, drug combination (37317-08-1) ; Aluminum Hydroxide (5QB0T2IUN0) ; Transketolase (EC 2.2.1.1) ; Magnesium Hydroxide (NBZ3QY004S)
Language	English
Publishing date	2013-12-01
Publishing country	Netherlands
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	1500523-9
ISSN	1873-4367 ; 0927-7765
ISSN (online)	1873-4367
ISSN	0927-7765
DOI	10.1016/j.colsurfb.2013.07.023
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