Anomeric Configuration Research Articles

Study on hydrolase mechanism of copper compound nanoparticles and its application in the evaluation of gut bacteria in aquatic environment

Conversing proteinaceous enzyme behavior into nanomaterials is intriguing academically, but the threshold from mimicry to accessing sophisticated biological entities has not yet been crossed. Herein, we disclosed the pan-glycoside hydrolases-like (p-GHs-like) activities of Cu3P and Cu2O nanoparticles and decently confirmed their consistent catalytic mechanism as natural glycoside hydrolase, that is, the precise bond breaking, anomeric carbon configuration and catalytic attack mode. We then introduced p-GHs-like NPs into Escherichia coli to establish a feedback regulatory model for the β-D-glucuronidase (expressed by uidA) that was initially expressed in trace amounts. An upregulation of uidA from 72 to 1000 counts was induced by the p-GHs-like activities via pre-released β-glucuronides derivatives, further contributing to 1–2 orders enhancement of the enzyme production. We unearthed the specific catalytic mechanism to unlock a black box of enzyme-like inorganic feedback on the natural enzyme synthesis process, pushing mimicry leaped to physiological behavior.

Supramolecular 3-d Metal 1,10-Phenanthroline Tartratostannates(IV) as Modifiers of α-L-Rhamnosidase Activity of Cryptococcus albidus, Eupenicillium erubescens and α-Galactosidase Activity of Penicillium restrictum

In recent years, the particular interest of researchers is focused on such enzymes as α-L-rhamnosidase and α-galactosidase. These enzymes are considered useful for various applications. α-L-rhamnosidases may be applied for debittering of citrus fruit juices, due to the less bitter taste of the derhamnosylated flavonones, for rhamnose production, and for the determination of the anomeric configuration in polysaccharides, glycosides and glycolipids. These enzymes may enhance wine aroma and flavonoid bioavailability, or assist in the synthesis of pharmaceuticals. α-Galactosidase finds application in many areas. It is widely used in the food industry to improve the quality of soy products by hydrolyzing indigestible galactosides such as raffinose and stachyose, in the processing of raw materials in order to increase the yield of sugar from molasses, and for the biotransformation of human blood erythrocytes of group B (III) in universal donor erythrocytes, as well as in enzyme therapy of some congenital disorders of sphingolipid metabolism. Earlier, as a result of screening microorganisms of different taxonomic groups, we has selected active α-L-rhamnosidase and α-galactosidase producers. One way to increase their activity is using various effector compounds capable of modifying the enzyme activity. The study of the influence of various effectors is one of the priority areas of modern research in biochemistry, biocoordination chemistry, and biotechnology. Recent advantages in the area of biocoordination chemistry revealed high activating properties of double heterometallic mixed-ligand coor dination compounds with germanium(IV)/tin(IV) tartaric complex anions and 1,10-phenanthroline/2,2`-bipyridine d-metallic cations. The aim is to estimate the enzyme-effector activity of five similar tartratostannates for the α-L-rhamnosidases of Cryptococcus albidus, Eupenicillium erubescens, and α-galactosidase of Penicillium restrictum. Methods. The activity of α-Galactosidase was determined using p-nitrophenyl-α-D-galactopyranoside («Sigma», USA) as a substrate. The activity of α-L-rhamnosidase was determined using the Davis method. As modifiers of enzyme activity, [Fe(phen)3]2[Sn2(μ-Tart)2(Н2Tart)2]·2H2O (1), [Co(phen)3]2[Sn2(μ-Tart)2(Н2Tart)2]·8H2O (2), [Ni(phen)3]2[Sn2(μ-Tart)2(Н2Tart)2]·2H2O (3), [Cu(phen)3]2[Sn2(μ-Tart)2(Н2Tart)2]·2H2O (4), and [Zn(phen)3]2[Sn2(μ-Tart)2(Н2Tart)2]·6H2O (5) were used. Results. The study of the effect of complexes 1—5, which are supramolecular salts consisting of the same tartrate stannate anion (electrophilic agent) and a 1,10-phenanthroline d-metal cation (nucleophilic agent), on the Cryptococcus albidus, Eupenicillium erubescens α-L-rhamnosidases, and Penicillium restrictum α-galactosidase showed that the compounds tested had a different influence on the enzymes’ activity. The catalytic activity of α-L-rhamnosidase is significantly influenced by all complexes. The effectiveness of compounds 1—5 for P. restrictum α-galactosidase was less pronounced in comparison with C. albidus and E. erubescens α-L-rhamnosidases. It was mostly at the control level. There was observed a certain pattern in the influence of complexes on α-L-rhamnosidases of Cryptococcus albidus and Eupenicillium erubescens. Compounds 2 and 5 turned out to be the most effective and activated enzymes by 500-900%. Conclusions. Compound 2 [Co(phen)3]2[Sn2(μ-Tart)2(Н2Tart)2]·8H2O is promising for further use as an effector of the α-L-rhamnosidase activity.

Primary Structure of Glycans by NMR Spectroscopy.

Glycans, carbohydrate molecules in the realm of biology, are present as biomedically important glycoconjugates and a characteristic aspect is that their structures in many instances are branched. In determining the primary structure of a glycan, the sugar components including the absolute configuration and ring form, anomeric configuration, linkage(s), sequence, and substituents should be elucidated. Solution state NMR spectroscopy offers a unique opportunity to resolve all these aspects at atomic resolution. During the last two decades, advancement of both NMR experiments and spectrometer hardware have made it possible to unravel carbohydrate structure more efficiently. These developments applicable to glycans include, inter alia, NMR experiments that reduce spectral overlap, use selective excitations, record tilted projections of multidimensional spectra, acquire spectra by multiple receivers, utilize polarization by fast-pulsing techniques, concatenate pulse-sequence modules to acquire several spectra in a single measurement, acquire pure shift correlated spectra devoid of scalar couplings, employ stable isotope labeling to efficiently obtain homo- and/or heteronuclear correlations, as well as those that rely on dipolar cross-correlated interactions for sequential information. Refined computer programs for NMR spin simulation and chemical shift prediction aid the structural elucidation of glycans, which are notorious for their limited spectral dispersion. Hardware developments include cryogenically cold probes and dynamic nuclear polarization techniques, both resulting in enhanced sensitivity as well as ultrahigh field NMR spectrometers with a 1H NMR resonance frequency higher than 1 GHz, thus improving resolution of resonances. Taken together, the developments have made and will in the future make it possible to elucidate carbohydrate structure in great detail, thereby forming the basis for understanding of how glycans interact with other molecules.

The collision-induced dissociation mechanism of sodiated Hex-HexNAc disaccharides.

Determining carbohydrate structures, such as their compositions, linkage positions, and in particular the anomers and stereoisomers, is a great challenge. Isomers of different anomers or stereoisomers have the same sequences of chemical bonds, but have different orientations of some chemical bonds which are difficult to be distinguished by mass spectrometry. Collision-induced dissociation (CID) tandem mass spectroscopy (MS/MS) is a widely used technique for characterizing carbohydrate structures. Understanding the carbohydrate dissociation mechanism is important for obtaining the structural information from MS/MS. In this work, we studied the CID mechanism of galactose-N-acetylgalactosamine (Gal-GalNAc) and glucose-N-acetylglucosamine (Glc-GlcNAc) disaccharides with 1→3 and 1→4 linkages. For Gal-GalNAc disaccharides, the CID mass spectra of sodium ion adducts show significant difference between the α- and β-anomers of GalNAc at the reducing end, while no difference in the CID mass spectra between two anomers of Glc-GlcNAc disaccharides was found. Quantum chemistry calculations show that for Gal-GalNAc disaccharides, the difference of the dissociation barriers between dehydration and glycosidic bond cleavage is significantly small in the β-anomer compared to that in the α-anomer; while these differences are similar between the α- and β-anomers of Glc-GlcNAc disaccharides. These differences can be attributed to the different orientations of hydroxyl and N-acetyl groups located at GalNAc and GlcNAc. The calculation results are consistent with the CID spectra of isotope labelled disaccharides. Our study provides an insight into the CID of 1→3 and 1→4 linked Gal-GalNAc and Glc-GlcNAc disaccharides. This information is useful for determining the anomeric configurations of GalNAc in oligosaccharides.

Matrix Assisted Laser Desorption Ionization – Tandem Time-of-Flight – Mass Spectrometry (MALDI-TOF/TOF-MS) Characterization of Oligosaccharides: Structural Identification and Differentiation

Mass spectrometry (MS) has been developed for high-sensitivity structural determination of carbohydrates. Due to the similarity of oligosaccharide structures, there is still insufficient information about the correlation between carbohydrate chemical structure and mass spectra. A series of trisaccharides containing different glycosidic linkages (1→2, 1→3, 1→4, 1→6, 2→1 and 2→6), anomeric configuration (α and β), and monosaccharide (pentose, hexose and hexuronic acid), as well as two cyclodextrins (α- and β-cyclodextrin) were systematically investigated using matrix assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI TOF/TOF MS) in positive and negative ion modes using super-DHB (2,5-dihydroxybenzoic acid) and harmine hydrochloride as matrices, respectively. Cross-ring cleavage generated by A-types ions with neutral losses of 48, 60, 78, 90, or 120 Da were observed in the negative ion MS/MS spectra, and neutral losses of 60, 90, or 120 Da were observed in the positive ion MS/MS spectra. Glycosidic cleavages were observed in both modes. The linkage isomers were unambiguously identified by those diagnostic fragment ions with their relative intensities. Furthermore, the correlation between linkage pattern and characteristic ions successfully allowed the characterization of polysaccharides with different structural features.

Krasilnikolides A and B and Detalosylkrasilnikolide A, Cytotoxic 20-Membered Macrolides from the Genus Krasilnikovia: Assignment of Anomeric Configuration by J-Based Configuration Analysis.

A chemical investigation of strain RD003821, belonging to the underexplored actinomycetes genus Krasilnikovia, led to the discovery of three novel polyketides: two 20-membered glycomacrolides, krasilnikolides A (1) and B (2), and an aglycone of 1, detalosylkrasilnikolide A (3). A major challenge in the structure elucidation of 1 was to determine the anomeric configuration of the α-l-6-deoxytalose (6dTal) unit, which was achieved by J-based configuration analysis (JBCA) that incorporated anomeric carbon- and proton-specific two-bond 13C-1H spin-spin coupling constants as diagnostic parameters. The updated criteria for the conformation/configuration assignment facilitated discrimination of three out of four stereochemical variants at the anomeric and the adjacent C2 positions, which expanded the scope of the JBCA method to determination of the anomeric configuration of aldohexopyranoses. Compounds 1 and 2 are the first macrolides decorated by 6dTal. Compounds 1-3 exhibited cytotoxicity against P388 murine leukemia cells with IC50 values of 14, 8.4, and 3.9 μM, respectively. In addition, 1-3 were antibacterial against the Gram-positive bacterium Kocuria rhizophila with MIC values of 25, 50, and 100 μg/mL. 1 was inhibitory against Staphylococcus aureus with an MIC of 50 μg/mL.

Sialylations reactions: Expanding the effect of silicon protecting groups at C-4

As a part of a general research goal into evaluating the effect of O-protecting groups in sialylation reactions, we compared the reactivities of phenylthio α- and β-sialyl donors protected at C-4 with tert-butyldimethyl silyl (TBDMS) and tri-isopropylsilyl (TIPS) groups in the coupling with primary and secondary galactosyl acceptors. The effect of the solvent and the donor's anomeric configuration were investigated and compared to previously published data. It is demonstrated that silicon groups at C-4 have a significant influence on sialylation reactions, and in general their overall performance is optimized with the use of acetonitrile.

Structural characterization of mushroom polysaccharides by cyclic ion mobility-mass spectrometry

Polysaccharides are biopolymers known to possess various bioactivities. Because of their molecular complexity, the structural characterization of polysaccharides remains challenging, and difficult to be completed with a single analytical method. In this study, a novel approach for the characterization of linkages and anomeric configuration of polysaccharides was proposed. Based on ion mobility-mass spectrometry (IM-MS), a database containing 5 glucotriose standards was set up. Information about the arrival time distribution and fragmentation patterns of these standards were included. The method was validated by three commercially available purified polysaccharides, namely laminarin, dextrin, and dextran, each having distinct connectivity and configuration of the glycosidic bonds. Lastly, the method was successfully applied to analyze polysaccharides prepared from three medicinal mushrooms, namely Xylaria nigripes, Grifola frondosa, and Laetiporus sulphureus. The results showed that water-soluble non-digestible polysaccharides of X. nigripes and G. frondosa were mainly composed of (1→3)-β-glucan, while that of L.sulphureus was composed of (1→3)-ɑ-glucan. The present method has the advantages of being simple in sample preparation and short analysis time.

Topological Dynamics of Micelles Formed by Geometrically Varied Surfactants

The molecular architecture of sugar-based surfactants strongly affects their self-assembled structure, i.e., the type of micelles they form, which in turn controls both the dynamics and rheological properties of the system. Here, we report the segmental and mesoscopic structure and dynamics of a series of C16 maltosides with differences in the anomeric configuration and degree of tail unsaturation. Neutron spin-echo measurements showed that the segmental dynamics can be modeled as a one-dimensional array of segments where the dynamics increase with inefficient monomer packing. The network dynamics as characterized by dynamic light scattering show different relaxation modes that can be associated with the micelle structure. Hindered dynamics are observed for arrested networks of worm-like micelles, connected to their shear-thinning rheology, while nonentangled diffusing rods relate to Newtonian rheological behavior. While the design of novel surfactants with controlled properties poses a challenge for synthetic chemistry, we demonstrate how simple variations in the monomer structure can significantly influence the behavior of surfactants.

Oxo-Rhenium-Mediated Allylation of Furanoside Derivatives: A Computational Study on the Mechanism and the Stereoselectivity

Properly substituted tetrahydrofuran (THF) rings are important building blocks in the synthesis of many natural metabolites. Having reliable procedures to control the stereoselectivity at the THF core while decorating it with different substituents is a fundamental requirement to achieve and fulfill the complexity of nature. We recently reported a new chemical approach to control the stereochemistry in the alkylation and arylation of furanoside derivatives by using a rhenium(V) complex to form an intermediate oxo-carbenium species able to react with proper soft nucleophiles. Here, we describe theoretical calculations, performed at the DFT B3LYP level, to disclose the important mechanistic features which regulate the entire catalytic cycle of the reaction of mono- and disubstituted furanosides with allyltrimethylsilane catalyzed by Re(O)Cl3(OPPh3)(Me2S). Moreover, the key factors governing the allylation step were investigated, confirming that the stereoselectivity, which is independent of the anomeric configuration of starting acetal, mainly arises from the orientation of the substituent at C-4, with only marginal contribution of the substituent at C-5. Finally, puckering Cremer–Pople parameters were used to take trace of the structural modifications throughout the catalytic cycle.

Multidimensional identification of disaccharide isomers based on non-covalent complexes and tandem mass spectrometry

Glycans are the most abundant organic polymers in nature. They are essential to living organisms and regulate a wide range of biological functions. However, mass spectrometry-based identification of glycan isomers remains challenging due to the complexity of their structures including their complex compositions, linkages, and anomeric configurations. In this study, two novel complex ions, the mononuclear copper-bound dimeric ions [(Cu2+)(A)(L-His)-H]+ and the mononuclear copper-bound quaternary ions [(Cu2+)(A)(L-Ser)3-H]+ (where A denotes a disaccharide, and L-Ser/His denotes l-serine/histidine), were designed for the collision-induced dissociation-based identification and relative quantification of 14 disaccharide isomers. When the unique fragmentation patterns of the above two types of complex ions were mapped into a three-dimensional vector, all the isomers were completely distinguished. Of note, the established method is able to identify mixtures of linkage isomers only using tandem mass spectrometry based on linkage-specific fragment ions of histidine-based complex ions. Finally, the method was successfully applied to the identification and relative quantification of two disaccharide isomers (lactose and sucrose) in dairy beverages. In conclusion, the established method is sensitive to subtle structural differences in disaccharide isomers and has the potential to be used for the differentiation of various glycans.

Acyl Group Migration in Pyranosides as Studied by Experimental and Computational Methods.

Acyl group migration affects the synthesis, isolation, manipulation and purification of all acylated organic compounds containing free hydroxyl groups, in particular carbohydrates. While several isolated studies on the migration phenomenon in different buffers have been reported, comprehensive insights into the overall migration process in different monosaccharides under similar conditions have been lacking. Here, we have studied the acyl migration in different monosaccharides using five different acyl groups by a combination of experimental, kinetic and theoretical tools. The results show that the anomeric configuration in the monosaccharide has a major influence on the migration rate, together with the relative configurations of the other hydroxyl groups and the nature of the migrating acyl group. Full mechanistic model, based on computations, demonstrates that the acyl migration proceeds through an anionic stepwise mechanism with linear dependence on the [OH−] and the pKa of the hydroxyl group toward which the acyl group is migrating.

Separation of disaccharide epimers, anomers and connectivity isomers by high resolution differential ion mobility mass spectrometry

Glycans are ubiquitous, structurally diverse molecules that have specific and general roles involving metabolism, structure, and cell-to-cell signaling. Functional specificity depends strongly on the complexity of structures that polysaccharides can adopt based on their subunit composition, length, extent of branching, glycosidic bond connectivity and anomeric configuration. However, a rapid and comprehensive characterization of glycan isomers can be challenging owing to limitations associated with their separation. Here, ten composition, anomeric and connectivity disaccharide isomers were separated and detected using high-resolution differential ion mobility-mass spectrometry (DMS-MS, also known as FAIMS). Focus was primarily directed to compositional isomers corresponding to epimers that differ by the axial or equatorial position of a single hydroxyl group. DMS resolving power was enhanced 14-fold primarily by increasing the fraction of helium in the ion carrier gas and lowering the flow rate. At relatively high disaccharide concentrations, DMS-MS of each disaccharide resulted in complex and unique multi-peak spectra with up to ten fully and partially resolved peaks for β-1,4-mannobiose (Man-1,4β-Man), which can be attributed to the DMS separation and subsequent dissociation of ionic non-covalently bound oligomers into monomer ions. Each DMS spectrum has at least one differentiating peak that is not in the other spectra, indicating that DMS can be used to fully or partially resolve composition, configuration and connectivity isomers. At relatively low disaccharide concentrations, mixtures of disaccharide epimers can also be readily separated by DMS. The integration of high-resolution, ambient pressure DMS with complementary reduced-pressure ion mobility and MS-based glycomics and glycoproteomics workflows may be useful for improving the characterization of glycans and glycosylated biomolecules.

More than a Leaving Group: N‐Phenyltrifluoroacetimidate as a Remote Directing Group for Highly α‐Selective 1,2‐cis Glycosylation

AbstractThe anomeric configuration can greatly affect the biological functions and activities of carbohydrates. Herein, we report that N‐phenyltrifluoroacetimidoyl (PTFAI), a well‐known leaving group for catalytic glycosylation, can act as a stereodirecting group for the challenging 1,2‐cis α‐glycosylation. Utilizing rapidly accessible 1,6‐di‐OPTFAI glycosyl donors, TMSOTf‐catalyzed glycosylation occurred with excellent α‐selectivity and broad substrate scope, and the remaining 6‐OPTFAI group can be cleaved chemoselectively. The remote participation of 6‐OPTFAI is supported by the first characterization of the crucial 1,6‐bridged bicyclic oxazepinium ion intermediates by low‐temperature NMR spectroscopy. These cations were found to be relatively stable and mainly responsible for the present stereoselectivities. Further application is highlighted in glycosylation reactions toward trisaccharide heparins as well as the convergent synthesis of chacotriose derivatives using a bulky 2,4‐di‐O‐glycosylated donor.

More than a Leaving Group: N-Phenyltrifluoroacetimidate as a Remote Directing Group for Highly α-Selective 1,2-cis Glycosylation.

The anomeric configuration can greatly affect the biological functions and activities of carbohydrates. Herein, we report that N-phenyltrifluoroacetimidoyl (PTFAI), a well-known leaving group for catalytic glycosylation, can act as a stereodirecting group for the challenging 1,2-cis α-glycosylation. Utilizing rapidly accessible 1,6-di-OPTFAI glycosyl donors, TMSOTf-catalyzed glycosylation occurred with excellent α-selectivity and broad substrate scope, and the remaining 6-OPTFAI group can be cleaved chemoselectively. The remote participation of 6-OPTFAI is supported by the first characterization of the crucial 1,6-bridged bicyclic oxazepinium ion intermediates by low-temperature NMR spectroscopy. These cations were found to be relatively stable and mainly responsible for the present stereoselectivities. Further application is highlighted in glycosylation reactions toward trisaccharide heparins as well as the convergent synthesis of chacotriose derivatives using a bulky 2,4-di-O-glycosylated donor.

1, 2-trans-Stereoselective 7-O-Glycosylation of Flavonoids with Unprotected Pyranoses by Mitsunobu Reaction.

The glycosylation of protecting-group-free pyranoses with flavonoids to generate flavonoid O-glycosides under Mitsunobu conditions was reported. The methodology allows to prepare a wide range of natural 7-flavonoid O-glycosides and their derivatives from commercially available chemicals in good to excellent yields with exclusive 1,2-trans-stereoselectivity regardless the anomeric configuration of employed pyranoses. The highly regioselective glycosylation was also achieved among different types of hydroxyl groups on the glycosyl acceptors.

D-Mannosamine hydrochloride (2-amino-2-deoxy-D-mannose hydrochloride): ionic hydrogen bonding in saccharides involving chloride and aminium ions.

D-Mannosamine hydrochloride (2-amino-2-deoxy-D-mannose hydrochloride), C6H14NO5+·Cl-, (I), crystallized from a methanol/ethyl acetate/n-hexane solvent mixture at room temperature in a 4C1 chair conformation that is slightly distorted towards the C3,O5B form. A comparison of the structural parameters of (I) with the corresponding parameters in α-D-glucosamine hydrochloride, (II), and β-D-galactosamine hydrochloride, (III)/(III'), was undertaken to evaluate the effects of ionic hydrogen bonding on structural properties. Three types of ionic hydrogen bonds are present in the crystals of (I)-(III)/(III'), i.e. N+-H...O, N+-H...Cl-, and O-H...Cl-. The exocyclic structural parameters in (I), (II), and (III)/(III') appear to be most influenced by this bonding, especially the exocyclic hydroxy groups, which adopt eclipsed conformations enabled by ionic hydrogen bonding to the chloride anion. Anomeric disorder was observed in crystals of (I), with an α:β ratio of 37:63. However, anomeric configuration appears to exert minimal structural effects; that is, bond lengths, bond angles, and torsion angles are essentially identical in both anomers. The observed disorder at the anomeric C atom of (I) appears to be caused by the presence of the chloride anion and atom O3 or O4 in proximal voids, which provide opportunities for hydrogen bonding to atom O1 in both axial and equatorial orientations.

Chiral evasion and stereospecific antifolate resistance in Staphylococcus aureus

Antimicrobial resistance presents a significant health care crisis. The mutation F98Y in Staphylococcus aureus dihydrofolate reductase (SaDHFR) confers resistance to the clinically important antifolate trimethoprim (TMP). Propargyl-linked antifolates (PLAs), next generation DHFR inhibitors, are much more resilient than TMP against this F98Y variant, yet this F98Y substitution still reduces efficacy of these agents. Surprisingly, differences in the enantiomeric configuration at the stereogenic center of PLAs influence the isomeric state of the NADPH cofactor. To understand the molecular basis of F98Y-mediated resistance and how PLAs' inhibition drives NADPH isomeric states, we used protein design algorithms in the osprey protein design software suite to analyze a comprehensive suite of structural, biophysical, biochemical, and computational data. Here, we present a model showing how F98Y SaDHFR exploits a different anomeric configuration of NADPH to evade certain PLAs' inhibition, while other PLAs remain unaffected by this resistance mechanism.

Shear-induced nano structural changes in micelles formed by sugar-based surfactants with varied anomeric configuration

Shear-induced nano structural changes in micelles formed by sugar-based surfactants with varied anomeric configuration

Cover Feature: Mutagenesis of Catalytic Nucleophile of β‐Galactosidase Retains Residual Hydrolytic Activity and Affords a Transgalactosidase (ChemCatChem 21/2021)

The Cover Feature shows an unexpected enzymatic reaction catalyzed by the mutant glycoside hydrolase enzyme – a glycosynthase. Glycosynthases are commonly considered to be hydrolytically inactive enzyme variants that can only process certain substrates of opposite anomeric configuration, such as glycosyl fluorides. In their Full Paper, M. Hovorková et al. show that this principle is not quite so versatile. The catalytic nucleophile mutant of β-galactosidase from Bacillus circulans (BgaD-A) retained traces of its hydrolytic activity and was able to process a β-galactoside as a galactosyl donor, affording disaccharides in a good yield. Thus, the mutation that typically yields glycosynthases surprisingly resulted in a transglycosidase. More information can be found in the Full Paper by M. Hovorková et al.