Tadao Kondo

Human Homolog of Caenorhabditis elegans sqv-3 Gene Is Galactosyltransferase I Involved in the Biosynthesis of the Glycosaminoglycan-Protein Linkage Region of Proteoglycans

A cDNA encoding a novel galactosyltransferase was identified based on BLAST analysis of expressed sequence tags, and the cDNA clones were isolated from a human melanoma line library. The new cDNA sequence encoded a type II membrane protein with 327 amino acid sequence and showed 38% homology to theCaenorhabditis elegans sqv-3 gene involved in the vulval invagination and oocyte development. Extracts from L cells transfected with the galactosyltransferase cDNA in an expression vector and a fusion protein with protein A exhibited marked galactosyltransferase activity specific forp-nitrophenyl-β-d-xylopyranoside. Moreover, transfection with the cloned cDNA restored glycosaminoglycan synthesis of galactosyltransferase I-deficient Chinese hamster ovary mutant pgsB-761 cells. Analysis of the enzyme product by β-galactosidase digestion, mass spectroscopy, and NMR spectroscopy revealed that the reaction product was formed via β-1,4 linkage, indicating that the enzyme is galactosyltransferase I (UDP-galactose:O-β-d-xylosylprotein 4-β-d-galactosyltransferase, EC 2.4.1.133) involved in the synthesis of the glycosaminoglycan-protein linkage region of proteoglycans.

Structure of gentiodelphin, an acylated anthocyanin isolated from Gentiana Makinoi, that is stable in dilute aqueous solution

Abstract Structure of gentiodelphin is determined to be 5, 3′-d8-O-(6-O- trans -caffeoylβ-D-glucosyl)-3-O-(β-D-glucosyl)delphinidin. The anthocyanin is stable in dilute neutral aqueous solution. This stabilization may be caused from intramoleculaur hydrophobic interactions among the aromatic nuclei; the anthocyanidin being sandwiched win between two caffeic acids.

An antifungal compound, 9,12,13-trihydroxy-(E)-10-octadecenoic acid, from Colocasia antiquorum inoculated with Ceratocystis fimbriata

Abstract An antifungal compound has been isolated from tubers of taro ( Colocasia antiquorum ) inoculated with black rot fungus ( Ceratocystis fimbriata ) and identified as 9,12,13-trihydroxy-( E )-10-octadecenoic acid.

Structure determination of heavenly blue anthocyanin, a complex monomeric anthocyanin from the morning glory Ipomoea tricolor, by means of the negative Noe method

Abstract The structure of heavenly blue anthocyanin was elucidated to be 3-0-(2-0-(6-0-( trans -3-0-(β-D-glucopyranosyl)caffeyl)-β-D-glucopyranosyl)-6-0 -( trans -4-0-(6-0-( trans -3-0-(β-D-glucopyranosyl)caffeyl)-β-D-gluco-pyranosyl)caffeyl)-β-D-glucopyranosyl)-5-0-(β-D-glucopyranosyl)peonidin by application of the negative NOE difference spectroscopy.

Copigmentation gives bluer flowers on transgenic torenia plants with the antisense dihydroflavonol-4-reductase gene

When anthocyanins in plants make complexes with copigments such as flavones or flavonols (copigmentation), the visible absorption maximum of the flowers is shifted so that it becomes longer: that is, the flowers look bluer. In an earlier study, our group reported the modification of flower color in torenia (Torenia fournieri Lind.) by re-introduction of the dihydroflavonol-4-reductase (DFR) gene or the chalcone synthase (CHS) gene. Our initial observation of torenia transformants was that plants with the antisense DFR gene produced bluer flowers than plants with the antisense CHS gene. In the present study we found that inactivation of the DFR gene by genetic transformation caused the accumulation of flavones - possible copigments - and that the resulting copigmentation likely to make the torenia flowers bluer. This method could be applied to other plant species to produce bluer flowers.

Intramolecular stacking conformation of gentiodelphin, a diacylated anthocyanin from Gentiana makinoi

Gentiodelphin from Gentiana makinoi is unusually stable in neutral aqueous solutions and may be stabilized by intramolecular sandwich-type stacking of two caffeic acids. Although in acidic methanol solution, evidence for intramolecular stacking of gentiodelphin was obtained from electronic spectra and 1H NMR analysis. Using computer-assisted conformational analysis with NOE constraints and bond angle constraints, we first established the intramolecular stacking conformation of aromatic acid to the anthocyanidin nucleus. Under acidic conditions, one caffeic acid attached at the glucose of the 2-position of the B-ring was stacked to the delphinidin nucleus but the other acid attached at the glucose of the 5-position was not stacked.

Structure of pamamycin-607, an aerial mycelium-inducing substance of Streptomyces alboniger

Abstract Pamamycin-607 with aerial mycelium-inducing activity has been isolated from Streptomyces alboniger , and its structure with the relative stereochemistry has been determined as a novel ionophore compound ( 1 ) on the basis of spectral analysis mainly by 2D 1 H 13 C and 1 H 1 H correlation NMR and NOE difference spectroscopy.

A NEW MOLECULAR MECHANISM OF BLUE COLOR DEVELOPMENT WITH PROTOCYANIN, A SUPRAMOLECULAR PIGMENT FROM CORNFLOWER, CENTAUREA CYANUS

Protocyanin (1), a blue pigment of Centaurea cyanus, is composed of six molecules each of malonylflavone (2) and succinylcyanin (3), complexed with magnesium and ferric ions. The blue color of 1 is developed by an LMCT interaction between anthocyanin and ferric ion, rather than arising from the formation of a simple anhydrobase anion of the chromophore. The supramolecular structure of 1 was elucidated.

Syntheses of (α2–9) and (α2–8) linked neuraminylneuraminic acid derivatives

Abstract A newly prepared glycosyl donor, the acetyl protected 2β-bromo-3β-hydroxy- N -acetylneuraminic ester was condensed with the protected 2-deoxy-2,3-dehydroneuraminic ester having a free hydroxy group at 9- or 8-position to form NeuAc(α2–9)NeuAc and NeuAc(α2–8)NeuAc linkage, respectively, which are involved in the group C meningococcal polysaccharides and gangliosides. The obtained 3β-hydroxy disaccharides were phenoxythiocarbonylated, reduced with tri- n -butylstannane, and deprotected to give the free glycosides in high yields.

Flavonol glycosides from flowers of Crocus speciosus and C. antalyensis

From the flower extracts of Crocus speciosus and C. antalyensis nine flavonol glycosides have been isolated. One of these products is a new flavonol glycoside identified as kaempferol 3-O-alpha-(2,3-di-O-beta-D-glucopyranosyl)rhamnopyranoside by UV, mass and NMR spectroscopy.