Champacyclin, a New Cyclic Octapeptide from Streptomyces Strain C42 Isolated from the Baltic Sea

New isolates of Streptomyces champavatii were isolated from marine sediments of the Gotland Deep (Baltic Sea), from the Urania Basin (Eastern Mediterranean), and from the Kiel Bight (Baltic Sea). The isolates produced several oligopeptidic secondary metabolites, including the new octapeptide champacyclin (1a) present in all three strains. Herein, we report on the isolation, structure elucidation and determination of the absolute stereochemistry of this isoleucine/leucine (Ile/Leu = Xle) rich cyclic octapeptide champacyclin (1a). As 2D nuclear magnetic resonance (NMR) spectroscopy could not fully resolve the structure of (1a), additional information on sequence and configuration of stereocenters were obtained by a combination of multi stage mass spectrometry (MSn) studies, amino acid analysis, partial hydrolysis and subsequent enantiomer analytics with gas chromatography positive chmical ionization/electron impact mass spectrometry (GC-PCI/EI-MS) supported by comparison to reference dipeptides. Proof of the head-to-tail cyclization of (1a) was accomplished by solid phase peptide synthesis (SPPS) compared to an alternatively side chain cyclized derivative (2). Champacyclin (1a) is likely synthesized by a non-ribosomal peptide synthetase (NRPS), because of its high content of (d)-amino acids. The compound (1a) showed antimicrobial activity against the phytopathogen Erwinia amylovora causing the fire blight disease of certain plants

Involvement and Unusual Substrate Specificity of a Prolyl Oligopeptidase in Class III Lanthipeptide Maturation

Lanthipeptides represent an important group of ribosomally synthesized and post-translationally modified peptides (RiPPs). Commonly, in the last steps of their maturation, a part of the peptide, termed the leader, is removed, providing the active compound. This contribution describes for the first time the identification of a protease involved in the removal of the leader peptide of a class III lanthipeptide. Four putative class III biosynthetic gene clusters were identified in bacterial genomes, each containing a gene encoding a prolyl oligopeptidase (POP). Further in vitro investigations of the gene cluster from Kribbella flavida, involving reconstitution of the biosynthesis of the new lanthipeptide flavipeptin, proved that a POP-type FlaP protease is responsible for leader removal. Interestingly, detailed in vitro studies of the substrate specificity revealed that FlaP is specific to the post-translationally modified peptide and can discriminate between N- and C-terminal rings. Therefore, it has been shown for the first time that factors other than size and amino acid sequence might be involved in substrate recognition by POPs

Bauteilintegrierte Heiz- und Haustechnik fuer zukuenftige Baukonzepte (Hybride Heizsysteme). Projektstufe 3/2: Umsetzung am Einfamilienhaus Zaberfeld Abschlussbericht

Hybride Heizsysteme sparen Heizenergie durch solare Energienutzung. In Phase 1 und 2 des Projekts wurde ein Hybridsystem entwickelt, optimiert und unter Laborbedingungen getestet. In Phase 3 war experimentell zu untersuchen, welche Heizenergieeinsparung sich unter praktischen Wohnbedingungen erzielen laesst und welche Temperaturen sich in Gebaeude und Hybridanlage unter sommerlichen und winterlichen Klimabedingungen einstellen. Die Messungen der Temperaturen von Gebaeude und Hybridanlage im Sommer ergab, dass keine Ueberhitzung im Gebaeude auftrat und dass bei Stillstand der Hybridanlage keine Schaeden an den verwendeten Materialien infolge zu hoher Temperaturen zu befuerchten sind. Der gemessene Heizenergieverbrauch betrug in der Heizperiode 1996/97 8524 kWh, was einen Anteil von 55% in der Energiebilanz auf der Gewinnseite und einen wohnflaechenbezogenen Verbrauch von 93,9 kWh/m"2 bedeutet. Der Anteil der Hydriddecke belaeuft sich auf 976 kWh entsprechend 6% in der Energiebilanz. Der Ausnutzungsgrad des Kollektors lag bei 15,3%. Die Mehrkosten fuer das Hybridsystem in der Prototypversion (Kleinstserie) belaufen sich auf 55190 DM, wovon auf die Kollektoren 25770 DM entfallen. In der weiteren Umsetzung von Hybridanlagen muss vordergruendig auf der Kostenseite angesetzt werden. Hier bietet sich an, statt Kollektoren Abluftfenster einzusetzen. Weitere Umsetzungsmassnahmen sind Erhoehung der Daemmschichtdicke zwischen Kollektor und Wand auf 100 mm, Schaffung einer homogeneren Temperaturverteilung in der Decke durch eine andere Rohrfuehrung und Kombination des Hybridsystems mit einem rasch regelnden Heizsystem. (orig.)Hybrid heating systems save heating energy by using solar energy. A hybrid system has been developed, optimized and tested under laboratory conditions in phase 1 and 2 of the project. The aim of phase 3 was to investigate which heating energy savings are possible under practical living conditions and which temperatures result in the building and the hybrid plant under summer and winter climate conditions. Temperature measurements in the building and the hybrid plant indicate, that no overheating occurs inside the building. Furthermore there is no reason for damage to the materials used because of overheating. The measured heating energy consumption within the heating period 1996/97 amounted to 8524 kWh contributing to 55% to the energy balance and an energy consumption value of 93,9 kWh per m"2 floor area. The percentage of hybrid system amounts to 6% to the energy balance. The collector efficiency was 15,3%. This prototype of a hybrid system costs 55190 DM, whereby the collector unit costs 25770 DM. Further realization of hybrid plants is only possible by reducing costs for instance by using windows producing warm air instead of collectors. Further steps are increasing the thickness of the insulation layer between collector and wall to 100 mm, optimizing layout of pipes making temperature distribution more homogeneous and combining the hybrid system with a fast reacting auxiliary heating system. (orig.)Available from TIB Hannover: RO 5074(1998,141)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Dissecting Reactions of Nonlinear Precursor Peptide Processing of the Class III Lanthipeptide Curvopeptin

Lanthipeptides are ribosomally synthesized peptides which undergo extensive post-translational modifications. In addition to novel structural features and bioactivities, the <i>in vitro</i> study on the biosynthesis of the class III lanthipeptide labyrinthopeptin revealed a unique C- to N-terminal directionality of biosynthetic processing. The recently described class III lanthipeptide curvopeptin allowed investigating the directionality aspect in much greater detail: Structural characterization of nine curvopeptin biosynthesis intermediates by high-resolution mass spectrometry combined with a deuterium-labeling approach enabled for the first time building a comprehensive biosynthesis model featuring all three post-translational modification reactions: phosphorylation, elimination, and cyclization. These results point to a nonlinear processing scheme with a predominant C → N-terminal directionality. Our data give important mechanistic insights into the concerted processing and directionality of the multifunctional class III modifying enzymes. The data are of significance in the light of obtaining a mechanistic understanding of the post-translational biosynthesis machinery of the growing variety of ribosomally synthesized and post-translationally modified peptides