Kenji Monde

Spirocyclization strategy toward indole phytoalexins. The first synthesis of (′)-1-methoxyspirobrassinin, (′)-1-methoxyspirobrassinol, and (′)-1-methoxyspirobrassinol methyl ether

Abstract The first syntheses of cruciferous indole phytoalexins (±)-1-methoxyspirobrassinin, (±)-1-methoxyspirobrassinol, (±)-1-methoxyspirobrassinol methyl ether as well as a new syntheses of phytoalexins (±)-spirobrassinin and cyclobrassinin were achieved by dioxane dibromide (DDB)-mediated spirocyclization of brassinin and its 1-substituted derivatives.

Efficient and versatile synthesis of mucin-like glycoprotein mimics

An efficient synthetic method of sequential glycopeptide-polymer by means of the combined chemical and enzymatic strategy was applied to the practical synthesis of some tandem repeating mucin-type glycoproteins. Versatility of the present synthetic strategy was demonstrated by elucidating some physicochemical and conformational analyses of these synthetic mucins.

Preparation of cruciferous phytoalexin related metabolites, (−)-dioxibrassinin and (−)-3-cyanomethyl-3-hydroxyoxindole, and determination of their absolute configurations by vibrational circular dichroism (VCD)

Abstract Cruciferous phytoalexin related metabolites, (−)-dioxibrassinin ( 1 ) and (−)-3-cyanomethyl-3-hydroxyoxindole ( 2 ) were prepared from isatin as racemates and were resolved by chiral HPLC. Their absolute configurations were determined by the new chiroptical technique, vibrational circular dichroism (VCD), as well as by the conventional electronic circular dichroism (ECD). It is concluded that the absolute configurations of the naturally occurring (−)- 1 and (−)- 2 are both S.

An Engineered Hyaluronan Synthase CHARACTERIZATION OF RECOMBINANT HUMAN HYALURONAN SYNTHASE 2 EXPRESSED IN ESCHERICHIA COLI

The Class I hyaluronan synthase (HAS) is a unique glycosyltransferase synthesizing hyaluronan (HA), a polysaccharide composed of GlcUA and GlcNAc, by using one catalytic domain that elongates two different monosaccharides. As for the synthetic mechanism, there are two alternative manners for the sugar elongation process. Some bacterial HASs add new sugars to the non-reducing end of the acceptor to grow polymers. On the other hand, some vertebrate enzymes seem to transfer sugars to the reducing end. Expression of vertebrate HASs as active and soluble proteins will accelerate further precise insight into mechanisms of sugar elongation reactions by natural HASs. Since large scale production of HA polymers and oligomers would become powerful tools both for basic studies and new biotechnology to create functional carbohydrates in medicinal purposes, advent of an efficient method for the expression of HASs in Escherichia coli is strongly expected. Here we communicate the first success of the production of recombinant human HAS2 proteins composed of only the catalytic region in E. coli as the active form. It was demonstrated that an engineered HAS2 expressed in E. coli exhibited significant activity to synthesize a mixture of HAS oligomers from 8-mer (HA8) to 16-mer (HA16). Engineered HAS2 prepared herein elongated sugars from exogenous tetrasaccharide to form polymers with a direction to the non-reducing end. According to the present results, large scale production of engineered recombinant HASs is to be performed using E. coli that will provide practical and economic advantages in manufacturing enzymes for use in the synthesis of various oligomeric HA molecules and their industrial applications.

Erythrocyte-like liposomes prepared by means of amphiphilic cyclodextrin sulfates

A novel class of sulfated glycolipids with excellent self-assembling capacity to form stable monolayers at an air-water interface and specific erythrocyte-like liposomes was synthesised from alpha, beta, and gamma-cyclodextrins as starting materials.