G. Hauser

The active conformation of avilamycin A is conferred by AviX12, a radical AdoMet enzyme.

The antibiotic avilamycin A is produced by Streptomyces viridochromogenes Tü57. Avilamycin belongs to the family of orthosomycins with a linear heptasaccharide chain linked to a terminal dichloroisoeverninic acid as aglycone. The gene cluster for avilamycin biosynthesis contains 54 open reading frames. Inactivation of one of these genes, namely aviX12, led to the formation of a novel avilamycin derivative named gavibamycin N1. The structure of the new metabolite was confirmed by mass spectrometry (MS) and NMR analysis. It harbors glucose as a component of the heptasaccharide chain instead of a mannose moiety in avilamycin A. Antibacterial activity tests against a spectrum of Gram-positive organisms showed that the new derivative possesses drastically decreased biological activity in comparison to avilamycin A. Thus, AviX12 seems to be implicated in converting avilamycin to its bioactive conformation by catalyzing an unusual epimerization reaction. Sequence comparisons grouped AviX12 in the radical S-adenosylmethionine protein family. AviX12 engineered with a His tag was overexpressed in Escherichia coli and purified by affinity chromatography. The iron sulfur cluster [Fe-S] present in radical AdoMet enzymes was detected in purified AviX12 by means of electron paramagnetic resonance spectroscopy.

Genes Involved in Formation and Attachment of a Two-Carbon Chain as a Component of Eurekanate, a Branched-Chain Sugar Moiety of Avilamycin A

ABSTRACT Eurekanate belongs to the important class of branched-chain carbohydrates present in a wide variety of natural sources. It is a component of avilamycin A, a potent inhibitor of bacterial protein synthesis targeting the 50S ribosomal subunit. The present work provides experimental proof for the function of two genes of the avilamycin biosynthetic gene cluster, aviB1 and aviO2, that are both involved in avilamycin structure modification. The functions of both genes were identified by gene inactivation experiments and nuclear magnetic resonance analyses of extracts produced by the mutants. We suggest that both AviO2 and AviB1 are involved in the biosynthesis of eurekanate within avilamycin biosynthesis. Moreover, two other genes (aviO1 and aviO3) have been inactivated, resulting in a breakdown of avilamycin production in the mutants ITO1 and ITO3, which clearly shows the essential role of both enzymes in avilamycin biosynthesis. The exact functions of both aviO1 and aviO3 remained unknown.

Klimaentlastung durch Massivholzbauarten (Teil 1)

Die Moglichkeit der Klimaentlastung durch die stoffliche Nutzung nachwachsender Rohstoffe im Bauwesen, insbesondere von Holz, findet bisher wenig Beachtung. Obwohl die Qualitat von Holz als wirksamer Kohlenstoffspeicher im Grundsatz bekannt ist und seine Berucksichtigung in der Gestaltung der Treibhausgasbudgets im Rahmen des Intergovernmental Panel on Climate Change (IPCC)-Prozesses entsprechend intensiv diskutiert wird, fehlt es noch an strategischen Ansatzen dieses Potential zu aktivieren. Insbesondere geben die ordnungsrechtlichen Anforderungen an die Energieeffizienz von Gebauden bislang keine Anreize fur eine stoffliche Verwendung von Holz als aktive CO2-Senke, obwohl hier mehr als in jedem anderen Nutzungsbereich von Holz eine dauerhafte verrottungsfreie Speichermoglichkeit von Kohlenstoffdioxid gegeben ist. In dem vorliegenden Beitrag wird die CO2-Senkenwirkung durch stoffliche Holznutzung im Bauwesen gegenuber den energiebedarfsinduzierten CO2-Emissionen neuer Gebaude abgewogen. Es zeigt sich, dass die stoffliche CO2-Senkenleistung im Zusammenspiel mit der heute erreichten Emissionsminderung durch Energieeffizienzmasnahmen und den Einsatz erneuerbarer Energietrager erheblich an Bedeutung gewinnt. Im Interesse des Klimaschutzes ist daher eine Steigerung des stofflichen Einsatzes von Holz anzustreben. Allerdings sind etliche Massivholzbausysteme auf Grund der schon kurzfristig anstehenden Verscharfungen der Anforderungen an die Energieeffizienz von Gebauden durch die Fortschreibung der Energieeinsparverordnung, vor allem aber durch die Forderungen der EU, ab 2018 bzw. 2020 ausschlieslich Niedrigstenergiehauser zuzulassen (Hauser, die nahezu keinen Primarenergiebedarf aufweisen), akut gefahrdet. Es wird daher ein Vorschlag erarbeitet, der Kohlenstoffsenkenleistung des Baustoffes Holz in den offentlich/rechtlichen Anforderungen an die Energieeffizienz von Gebauden Rechnung tragen zu konnen. Using solid wood construction methods in order to reduce emissions affecting the climate; principles and options for reducing the CO2 output created by external building components by using solid wood construction as part of the legal requirements for the energy efficiency of buildings, part 1. Up to now, the use of renewable resources, particularly timber, in order to reduce emissions affecting the climate has not received much attention. In spite of the fact that the properties of timber as an effective carbon store are well known in principle and its use has been extensively discussed for the purpose of determining the greenhouse gas budget within the context of the Intergovernmental Panel on Climate Change (IPCC) process, there is still a lack of strategic approaches to activate this potential. In particular, the statutory requirements for the energy efficiency of buildings have up to now not provided any incentives for the use of timber as a construction material in spite of the fact that timber provides a more durable and lasting carbon dioxide storage opportunity in construction than in any other application of the material. The article below weighs up the CO2 sink effect through use in construction compared with the CO2 emissions of new buildings created by the demand for energy. It is shown that the CO2 sink effect of timber in combination with the emission reductions through energy efficiency measures achievable today, and the use of renewable fuels is of considerable significance. It follows that the increased use of timber as a building material is desirable in the interest of climate protection. Against this background it is worth noting that many solid timber construction systems are currently in danger of being outlawed by the increased requirements for the energy efficiency of buildings which are imminent through the new revision of the Energy Conservation Directive and, above all, the EU demands for extremely low energy houses (houses which have an almost zero demand for primary energy) from 2018/2020. For this reason, the submitted proposal suggests ways of adequately representing the carbon sink effect of timber as a construction material in the statutory requirements for the energy efficiency of buildings.

Energieeinsparung in Gebäuden ndash; aktueller denn je!: Anforderungskonzept EnEV 2006 ndash; Vision Nachhaltigkeitsvektor

Die Notwendigkeit zur Energieeinsparung im Verbrauchssektor Gebaude resultiert aus den Aspekten Umweltschutz, Minderung der Importabhangigkeit, Senkung der zweiten Miete, Bausubstanz- und Werterhaltung sowie Komfortsteigerung und Ankurbelung der Bauwirtschaft. Die vorliegenden Einsparpotentiale sind fur den Wohngebaudebestand gut quantifizierbar, bei Nichtwohngebauden ist der Kenntnisstand deutlich geringer. Die durch die EU-Richtlinie “Gesamtenergieeffizienz von Gebauen” erforderlichen Neuerungen gegenuber der Energieeinsparverordnung (EnEV) 2002 liegen im wesentlichen in der Erfassung des Kunstlichtstrom- und des Kuhlenergiebedarfs. Beide Grosen spielen im Wohnungsbau praktisch keine Rolle. Deshalb erscheint es insbesondere angesichts des vorherrschenden Zeitdrucks zur Umsetzung der EU-Richtlinie zur Gesamtenergieeffizienz von Gebauden bis 2006 sinnvoll, die bisherige Behandlung des Wohnungsbaus beizubehalten. Fur Nichtwohngebaude liegen auch in den Bedarfsbereichen Heizung, Warmwasser und Luftung z. T. stark abweichende Verhaltnisse vom Wohnungsbau vor, auserdem kann die Erfassung des Kunstlichtstrom- und des Kuhlenergiebedarfs von groser Bedeutung sein. Fur diese Gebaude bedarf es neuer Berechnungsalgorithmen und der Formulierung von Anforderungen. Die Pramisse des vorgestellten Konzepts ist die nutzungsspezifische Formulierung der Anforderungen. Aus pragmatischen Grunden wird eine “Referenzgebaudemethode” empfohlen. Neben dem Aspekt der Energieeinsparung wird fur die Gebaudefunktion “Raumkonditionierung” die Einfuhrung eines Nachhaltigkeitsvektors vorgeschlagen. Fur die Beurteilungskriterien werden objektive Bewertungsfaktoren B eingefuhrt, die um individuelle Wichtungsfaktoren W erganzt werden. Energy saving in buildings ndash; more updated then ever! Concept of requirements EnEV 2006 ndash; vision vector of sustainability The necessity to conservate energy in the sector of energy consumption in buildings is a result of the aspects such as environment protection, decrease of dependency on import, lowering of second hires, conservation of basic fabric and value, as well as increase of comfort and pump priming of the building industry. Energy saving potentials are well quantifiable for the stock of residential buildings, at non-residential buildings the state of knowledge is clearly lower. The improvements from the Energy Performance of Buildings Directive (EPBD) compared to the German energy saving ordinance EnEV 2002 contain mainly the consideration of electricity for artificial lighting and cooling energy. Both components virtually do not play any role in residential buildings. Facing the predominant pressure of time ndash; the EPBD has to be converted until 2006 ndash; it seems to make sense to hold the present treatment of residential buildings. For space heating, hot water preparation and ventilation, there exist partly highly differing proportions in non-residential buildings in contrast to residential buildings; electricity for artificial lighting and cooling energy may become primarily important. For non-residential buildings, there is a need for development of new calculation methods and a new concept to formalize requirements. The premise of the presented concept is the formulation of usage-specified requirements. For pragmatic reasons, a “method of reference buildings” is recommended. In addition to the idea of energy saving, for the function of “room conditioning”, a vector of sustainability is proposed. For all rating criterions, objective evaluation factors B are established, which though are supplemented with weighting factors W.