Kazuo Furihata

The structure of neocarzinostatin chromophore possessing a novel bicyclo-[7,3,0]dodecadiyne system

Abstract The structure of the chromophore of an antitumor antibiotic neocarzinostatin has been elucidated as a bicycro[7,3,0]dodecadiyne system having naphthalenecarboxylic acid, aminosugar and ethylene carbonate units.

An Alternative Menaquinone Biosynthetic Pathway Operating in Microorganisms

In microorganisms, menaquinone is an obligatory component of the electron-transfer pathway. It is derived from chorismate by seven enzymes in Escherichia coli. However, a bioinformatic analysis of whole genome sequences has suggested that some microorganisms, including pathogenic species such as Helicobacter pylori and Campylobacter jejuni, do not have orthologs of the men genes, even though they synthesize menaquinone. We deduced the outline of this alternative pathway in a nonpathogenic strain of Streptomyces by bioinformatic screening, gene knockouts, shotgun cloning with isolated mutants, and in vitro studies with recombinant enzymes. As humans and commensal intestinal bacteria, including lactobacilli, lack this pathway, it represents an attractive target for the development of chemotherapeutics.

SIMULTANEOUS OPERATION OF THE MEVALONATE AND NON-MEVALONATE PATHWAYS IN THE BIOSYNTHESIS OF ISOPENTENYL DIPHOSPHATE IN STREPTOMYCES AERIOUVIFER

Abstract Labeling experiments using [1,2-13C2]acetate and [U-13C6]glucose on menaquinone and naphterpin produced by Streptomyces aeriouvifer proved simultaneous operation of the mevalonate and non-mevalonate pathways for the formation of isopentenyl diphosphate in this organism.

Constant time HMBC (CT-HMBC), a new HMBC technique useful for improving separation of cross peaks

Abstract New NMR pulse sequences CT-HMBC-1 and CT-HMBC-2 which incorporate constant time evolution period are more useful than the conventional HMBC technique for improving separation of cross peaks.

J-Resolved HMBC, a new NMR technique for measuring heteronuclear long-range coupling constants

Abstract A new NMR pulse sequence that incorporates J -scaling into HMBC enables efficient measurement of heteronuclear long-range coupling.

Structure of a New Antibiotic, Roseophilin

Abstract The structure of a new antibiotic, roseophilin, was elucidated to be as shown in Fig. 1 by NMR spectral analysis including a variety of two-dimensional techniques. Roseophilin was found to possess a novel skeleton containing pyrrole and furan moieties.

Spiruchostatins A and B, novel gene expression-enhancing substances produced by Pseudomonas sp.

Abstract Spiruchostatins A and B were isolated from Pseudomonas sp. as gene expression-enhancing substances. They possess novel bicyclic depsipeptides involving 4-amino-3-hydroxy-5-methylhexanoic acid and 4-amino-3-hydroxy-5-methylheptanoic acid residues, respectively, as shown in Fig. 1 Download high-res image (1KB) Download full-size image Figure 1 . Structures of spiruchostatins A ( 1 ) and B ( 2 ). .

Eubacterial Diterpene Cyclase Genes Essential for Production of the Isoprenoid Antibiotic Terpentecin

A gene cluster containing the mevalonate pathway genes (open reading frame 2 [ORF2] to ORF7) for the formation of isopentenyl diphosphate and a geranylgeranyl diphosphate (GGDP) synthase gene (ORF1) had previously been cloned from Streptomyces griseolosporeus strain MF730-N6, a diterpenoid antibiotic, terpentecin (TP) producer (Y. Hamano, T. Dairi, M. Yamamoto, T. Kawasaki, K Kaneda, T. Kuzuyama, N. Itoh, and H. Seto, Biosci. Biotech. Biochem. 65:1627-1635, 2001). Sequence analysis in the upstream region of the cluster revealed seven new ORFs, ORF8 to ORF14, which were suggested to encode TP biosynthetic genes. We constructed two mutants, in which ORF11 and ORF12, which encode a protein showing similarities to eukaryotic diterpene cyclases (DCs) and a eubacterial pentalenene synthase, respectively, were inactivated by gene disruptions. The mutants produced no TP, confirming that these cyclase genes are essential for the production of TP. The two cyclase genes were also expressed in Streptomyces lividans together with the GGDP synthase gene under the control of the ermE* constitutive promoter. The transformant produced a novel cyclic diterpenoid, ent-clerod-3,13(16),14-triene (terpentetriene), which has the same basic skeleton as TP. The two enzymes, each of which was overproduced in Escherichia coli and purified to homogeneity, converted GGDP into terpentetriene. To the best of our knowledge, this is the first report of a eubacterial DC.

Versipelostatin, a novel GRP78/Bip molecular chaperone down-regulator of microbial origin

Abstract We discovered a novel down-regulator of grp 78 gene expression designated as versipelostatin from the culture broth of Streptomyces versipellis 4083-SVS6. Its structure was determined to be a macrocyclic compound consisting of an α-acyltetronic acid and sugar moieties.

Roasting Process of Coffee Beans as Studied by Nuclear Magnetic Resonance: Time Course of Changes in Composition

In this paper, we report a (1)H and (13)C nuclear magnetic resonance (NMR)-based comprehensive analysis of coffee bean extracts of different degrees of roast. The roasting process of coffee bean extracts was chemically characterized using detailed signal assignment information coupled with multivariate data analysis. A total of 30 NMR-visible components of coffee bean extracts were monitored simultaneously as a function of the roasting duration. During roasting, components such as sucrose and chlorogenic acids were degraded and components such as quinic acids, N-methylpyridinium, and water-soluble polysaccharides were formed. Caffeine and myo-inositol were relatively thermally stable. Multivariate data analysis indicated that some components such as sucrose, chlorogenic acids, quinic acids, and polysaccharides could serve as chemical markers during coffee bean roasting. The present composition-based quality analysis provides an excellent holistic method and suggests useful chemical markers to control and characterize the coffee-roasting process.