Copper Complexes as Bioinspired Models for Lytic Polysaccharide Monooxygenases.

We report here two copper complexes as first functional models for lytic polysaccharide monooxygenases, mononuclear copper-containing enzymes involved in recalcitrant polysaccharide breakdown. These complexes feature structural and spectroscopic properties similar to those of the enzyme. In addition, they catalyze oxidative cleavage of the model substrate p-nitrophenyl-β-d-glucopyranoside.

Inhibitory properties of 1,4-dideoxy-1,4-imino-d-arabinitol (DAB) derivatives acting on glycogen metabolising enzymes.

Glycogen synthase (GS) and glycogen phosphorylase (GP) are the key enzymes that control, respectively, the synthesis and degradation of glycogen, a multi-branched glucose polymer that serves as a form of energy storage in bacteria, fungi and animals. An abnormal glycogen metabolism is associated with several human diseases. Thus, GS and GP constitute adequate pharmacological targets to modulate cellular glycogen levels by means of their selective inhibition.

Inhibitor versus chaperone behaviour of d-fagomine, DAB and LAB sp(2)-iminosugar conjugates against glycosidases: A structure-activity relationship study in Gaucher fibroblasts.

A library of sp(2)-iminosugar conjugates derived from the piperidine iminosugar d-fagomine and the enantiomeric pyrrolidine iminosugars DAB and LAB has been generated in only two steps involving direct coupling of the fully unprotected polyhydroxylated heterocycles with isothiocyanates, to give monocyclic thiourea adducts, and further intramolecular nucleophilic displacement of the δ-located primary hydroxyl group by the thiocarbonyl sulphur atom, affording bicyclic isothioureas. These transformations led to a dramatic shift in the inhibitory selectivity from α- to β-glucosidases, with inhibition potencies that depended strongly on the nature of the aglycone-type moiety in the conjugates. Some of the new derivatives behaved as potent inhibitors of human β-glucocerebrosidase (GCase), the lysosomal enzyme whose dysfunction is responsible for Gaucher disease.

Casuarine stereoisomers from achiral substrates: chemoenzymatic synthesis and inhibitory properties.

A straightforward chemoenzymatic synthesis of four uncovered casuarine stereoisomers is described. The strategy consists of L-fuculose-1-phosphate aldolase F131A-variant-catalyzed aldol addition of dihydroxyacetone phosphate to aldehyde derivatives of 1,4-dideoxy-1,4-imino-D-arabinitol (DAB) and its enantiomer (LAB) and subsequent one-pot catalytic deprotection-reductive amination. DAB and LAB were obtained from dihydroxyacetone and aminoethanol using D-fructose-6-phosphate aldolase and L-rhamnulose-1-phosphate aldolase catalysts, respectively.

Chemo-enzymatic synthesis and glycosidase inhibitory properties of DAB and LAB derivatives.

A chemo-enzymatic strategy for the preparation of 2-aminomethyl derivatives of (2R,3R,4R)-2-(hydroxymethyl)pyrrolidine-3,4-diol (also called 1,4-dideoxy-1,4-imino-D-arabinitol, DAB) and its enantiomer LAB is presented. The synthesis is based on the enzymatic preparation of DAB and LAB followed by the chemical modification of their hydroxymethyl functionality to afford diverse 2-aminomethyl derivatives. This strategy leads to novel aromatic, aminoalcohol and 2-oxopiperazine DAB and LAB derivatives.

D-fructose-6-phosphate aldolase in organic synthesis: cascade chemical-enzymatic preparation of sugar-related polyhydroxylated compounds.

Novel aldol addition reactions of dihydroxyacetone (DHA) and hydroxyacetone (HA) to a variety of aldehydes catalyzed by D-fructose-6-phosphate aldolase (FSA) are presented. In a chemical-enzymatic cascade reaction approach, 1-deoxynojirimycin and 1-deoxymannojirimycin were synthesized starting from (R)- and (S)-3-(N-Cbz-amino)-2-hydroxypropanal, respectively. Furthermore, 1,4-dideoxy-1,4-imino-D-arabinitol and 1,4,5-trideoxy-1,4-imino-D-arabinitol were prepared from N-Cbz-glycinal.