The coprophilic ascomycete Coniochaeta ellipsoidea DSM 13856 forms the new antibiotic coniosetin (1) in surface cultures grown on a medium containing malt extract and oatmeal. The structure of the compound C25H35NO4, MW 413, was determined by 2D-NMR and mass spectrometric studies. Coniosetin belongs to the class of tetramic acids; it consists of a substituted aliphatic bicyclic ring system linked to a tetramic acid subunit through a carbonyl center. The absolute configuration was determined by measuring its circular dichroism spectrum and comparing the data with those of equisetin. Coniosetin has a pronounced antibacterial and antifungal action, inhibiting even multi drug-resistant strains of negative bacteria.An obvious consequence of the development of resistance by pathogenic microorganisms1) is a growing demand for new medicines for the control of infectious diseases. However, a review article by J. J. BRONSON and J.

The novel peptide feglymycin has been isolated from cultures of Streptomyces sp. DSM 11171 by solid phase extraction, size exclusion chromatography and repeated reversed-phase chromatography. The molecular weight was found to be 1900.90 g/mol and the molecular formula is C95H97N13O30. Feglymycin contains 13 amino acids of which four are 3-hydroxyphenylglycine and five are 3,5-dihydroxyphenylglycine residues. The

Recombinant Desulfovibrio vulgaris flavodoxin (molecular mass 16.3 kDa) was produced in Escherichia coli. The oxidized protein has been investigated with a combination of homonuclear and heteronuclear two-dimensional and heteronuclear three-dimensional NMR spectroscopy. Sequencespecific assignment of all backbone and most of the side chain 'H and 15N resonances has been obtained. The secondary structure has been inferred from the pattern of sequential, medium-, and long-range NOES, together with information about slowly exchanging amide hydrogens and HN-W spin-spin coupling constants. In solution, flavodoxin consists of a five-stranded parallel B-sheet and four a-helices. Residues 3-9, 32-36, 52-58, 87-96, and 123-128 are involved in the P-sheet whereas the a-helical regions comprise residues 13-28, 69-76, 104-114, and 134-148. Several proton resonances of the bound flavin mononucleotide cofactor have been assigned. NOE contacts between the prosthetic group and the apoprotein have been detected.Desulfovibrio vulgaris flavodoxin is a member of a group of small microbial electron-transfer proteins which contain a molecule of non-covalently bound FMN as their redox-active group. It consists of 148 amino acid residues and has a molecular mass of 16.3 kDa (Dubourdieu and Fox, 1977). The protein-bound flavin can occur in three distinct redox states : an oxidized (quinone), a one-electron-reduced (semiquinone) and a two-electron-reduced (hydroquinone) form (Ghisla and Massey, 1989). In most physiological reactions the flavodoxins shuttle between the one-electron-reduced and the twoelectron-reduced state (Simondson and Tollin, 1980). The redox potentials for this transition vary from -320 mV to -518 mV among flavodoxins from different organisms (Vervoort, 1991 ;Deistung and Thorneley, 1986), whereas the value for the free FMN is -124 mV (Anderson, 1983). This indicates that the binding of the flavin to the apoflavodoxin causes significant changes in its redox properties. Ring strain, the burial of charge in a hydrophobic environment,

Two novel compounds, kodaistatin A, C35H34On, molecular weight 630, and kodaistatin C, C35H34O12,molecular weight 646, have been isolated from cultures ofAspergillus terreus Thorn DSM1 1247 by solid-phase extraction, size-exclusion chromatography, and various preparative HPLCsteps. The use of a range of 2D NMRmeasurements, in particular 13C-13C correlation measurements, has led to the clarification of the structure of kodaistatin A. Kodaistatin C is a hydroxylated derivative of kodaistatin A. Both natural products contain hydroxylated aspulvinones and identical highly substituted polyketide units. An X-ray single crystal structure analysis of aspulvinon E demonstrated the z-configuration at the central double bond. The kodaistatins are effective inhibitors of the glucose-6-phosphate translocase component of the glucose-6-phosphatase system (EC 3.1.3.9), an enzyme system which is important for the

The new pluramycin-type antibiotics pluraflavin A, C43H54N2O14, pluraflavin B, C43H56N2O15, and pluraflavin E, C36H41NO14 were isolated from cultures of the Saccharothrix species DSM12931. The structures of the novel compounds were elucidated with the aid of 2D NMR and mass spectrometric investigations.The characteristic structural element of pluraflavins A and B is an additional 4-epi-vancosamine unit at position 13 of the anthraquinone-7-pyrone ring system. Pluraflavin E has a carboxyl group in this position. Pluraflavin A has a reactive dimethyl epoxide side chain at position 2 of the anthraquinone-7-pyrone aglycon, which may explain the high activity of the antibiotic.The outstanding biological characteristic of pluraflavin A is its powerful, organ-dependent cytostatic action: the IC50 in the colon carcinoma proliferation assay is in the subnanomolar range.