41 research outputs found

    Globin-like proteins in Caenorhabditis elegans: in vivo localization, ligand binding and structural properties

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    Background: The genome of the nematode Caenorhabditis elegans contains more than 30 putative globin genes that all are transcribed. Although their translated amino acid sequences fit the globin fold, a variety of amino-acid substitutions and extensions generate a wide structural diversity among the putative globins. No information is available on the physicochemical properties and the in vivo expression. Results: We expressed the globins in a bacterial system, characterized the purified proteins by optical and resonance Raman spectroscopy, measured the kinetics and equilibria of O2 binding and determined the crystal structure of GLB-1* (CysGH2 T Ser mutant). Furthermore, we studied the expression patterns of glb-1 (ZK637.13) and glb-26 (T22C1.2) in the worms using green fluorescent protein technology and measured alterations of their transcript abundances under hypoxic conditions.GLB-1* displays the classical three-over-three α-helical sandwich of vertebrate globins, assembled in a homodimer associated through facing E- and F-helices. Within the heme pocket the dioxygen molecule is stabilized by a hydrogen bonded network including TyrB10 and GlnE7.GLB-1 exhibits high ligand affinity, which is, however, lower than in other globins with the same distal TyrB10-GlnE7 amino-acid pair. In the absence of external ligands, the heme ferrous iron of GLB-26 is strongly hexacoordinated with HisE7, which could explain its extremely low affinity for CO. This globin oxidizes instantly to the ferric form in the presence of oxygen and is therefore incapable of reversible oxygen binding. Conclusion: The presented data indicate that GLB-1 and GLB-26 belong to two functionally-different globin classes

    Streptocollin, a Type IV Lanthipeptide Produced by Streptomyces collinus Tü 365

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    Lanthipeptides are ribosomally synthesized and post-translationally modified microbial secondary metabolites. Here, we report the identification and isolation of streptocollin from Streptomyces collinus Tü 365, a new member of class IV lanthipeptides. Insertion of the constitutive ermE* promoter upstream of the lanthipeptide synthetase gene stcL resulted in peptide production. The streptocollin gene cluster was heterologously expressed in S. coelicolor M1146 and M1152 with 3.5- and 5.5-fold increased yields, respectively. The structure and ring topology of streptocollin were determined by high resolution MS/MS analysis. Streptocollin contains four macrocyclic rings, with one lanthionine and three methyllanthionine residues. To the best of our knowledge, this is the first report on the isolation of a class IV lanthipeptide in preparative amounts, and on the successful heterologous expression of a class IV lanthipeptide gene cluster

    Revolution postponed? Tracing the development and limitations of open content filmmaking

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    Networked information technologies have brought about extensive changes in the production and distribution of creative cultural work. Inspired by the widespread success of Free-Libre/Open Source Software (FLOSS), many proponents of open access advocate reconceptualisation of existing legal protection frameworks in creative works. This paper traces the attempted appropriation of Creative Commons (CC) licences by filmmakers and the consequent formation of an Open Content Filmmaking (OCF) movement. OCF proponents articulated notions of technology-enabled transformation in content creation and distribution, similar to those that inspire the visions of FLOSS and CC advocates. It examines how these creators attempted to address the relevance of openness to their own activities and develop practical open models for filmmaking. Difficulties experienced in establishing viable livelihoods with OCF (as FLOSS developers had done), created tensions between those with a pragmatic or more ideological orientation. The initial vision of a consistent OCF movement, enabled by CC, thus became fragmented. In contrast to FLOSS, where many actors were able to find ways to develop sustainable careers within the industry while contributing to Open Source Software, such generic strategies have not readily emerged for OCF. Drawing insights from Sørensen’s (1996) Social Learning framework (Learning technology, constructing culture. Sociotechnical change as social learning: University of Trondheim, STS working paper 18/96) in this paper we untangle the elaborate but often messy strategies deployed by Open Content Filmmakers (OCFs) and trace the multiple and often partial ways they have worked out to utilise CC elements and tools in producing, monetising and distributing their films

    The Sail-Backed Reptile Ctenosauriscus from the Latest Early Triassic of Germany and the Timing and Biogeography of the Early Archosaur Radiation

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    Background Archosaurs (birds, crocodilians and their extinct relatives including dinosaurs) dominated Mesozoic continental ecosystems from the Late Triassic onwards, and still form a major component of modern ecosystems (>10,000 species). The earliest diverse archosaur faunal assemblages are known from the Middle Triassic (c. 244 Ma), implying that the archosaur radiation began in the Early Triassic (252.3–247.2 Ma). Understanding of this radiation is currently limited by the poor early fossil record of the group in terms of skeletal remains. Methodology/Principal Findings We redescribe the anatomy and stratigraphic position of the type specimen of Ctenosauriscus koeneni (Huene), a sail-backed reptile from the Early Triassic (late Olenekian) Solling Formation of northern Germany that potentially represents the oldest known archosaur. We critically discuss previous biomechanical work on the ‘sail’ of Ctenosauriscus, which is formed by a series of elongated neural spines. In addition, we describe Ctenosauriscus-like postcranial material from the earliest Middle Triassic (early Anisian) Röt Formation of Waldhaus, southwestern Germany. Finally, we review the spatial and temporal distribution of the earliest archosaur fossils and their implications for understanding the dynamics of the archosaur radiation. Conclusions/Significance Comprehensive numerical phylogenetic analyses demonstrate that both Ctenosauriscus and the Waldhaus taxon are members of a monophyletic grouping of poposauroid archosaurs, Ctenosauriscidae, characterised by greatly elongated neural spines in the posterior cervical to anterior caudal vertebrae. The earliest archosaurs, including Ctenosauriscus, appear in the body fossil record just prior to the Olenekian/Anisian boundary (c. 248 Ma), less than 5 million years after the Permian–Triassic mass extinction. These earliest archosaur assemblages are dominated by ctenosauriscids, which were broadly distributed across northern Pangea and which appear to have been the first global radiation of archosaurs

    Complete Genome Sequence of the Actinobacterium Amycolatopsis japonica MG417-CF17T (=DSM 44213T) producing (S,S)-N,N'-ethylenediaminedisuccinic acid

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    Stegmann E, Albersmeier A, Spohn M, et al. Complete Genome Sequence of the Actinobacterium Amycolatopsis japonica MG417-CF17T (=DSM 44213T) producing (S,S)-N,N'-ethylenediaminedisuccinic acid. Journal of biotechnology. 2014;189:46-47.: We report the complete genome sequence of Amycolatopsis japonica MG417-CF17(T) (=DSM 44213(T)) which was identified as the producer of (S,S)-N,N'-ethylenediamine-disuccinic acid during a screening for phospholipase C inhibitors. The genome of A. japonica MG417-CF17(T) consists of two replicons: the chromosome (8,961,318 bp, 68.89 % G+C content) and the plasmid pAmyja1 (92,539 bp, 68.23 % G+C content), encoding a total of 8,422 protein coding genes. Analysis of the sequence data revealed 30 clusters encoding the biosynthesis of secondary metabolites
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