Paul Celan - poetique de la rencontre en quete de l'etre humain

This article deals with Paul Celans poetics of the encounter as a reflection on the anthropological question.

Verwirklichende Raume - Poetik und Raumkonzeption bei Paul Celan und Martin Buber

This article with the conception of space in Paul Celan's poetics, comparing it to Martin Buber's and developing a notion of 'realisation', important to both Celan and Buber. Partant du concept du fantastique en tant qu'espace dans laquelle les phénomènes sont véritablement perçus au lieu de simplement se dérouler, l'article montre comment la rupture avec la réalité accoutumée peut mener à une sensation intense de l'être. Chez Martin Buber se trouve la description d'un telle espace, où l'unité est créée à partir de la polarité de tout ce qui est. Le poème peut représenter un exemple d'un tel espace « réalisant ». La conception de l'espace chez Buber est démontrée en dialogue avec le poème STEHEN de Paul Celan, afin de montrer comment le monde réifié est « réalisé » par la poésie. Ainsi sont mis en valeur le rapport mutuel et le lien indispensable entre réalités sociales et la réalité du non-espace.

Biosynthesis pathway of ADP-L-glycero-beta-D-manno-heptose in Escherichia coli

The steps involved in the biosynthesis of the ADP-L-glycero-beta-D-manno-heptose (ADP-L-beta-D-heptose) precursor of the inner core lipopolysaccharide (LPS) have not been completely elucidated. In this work, we have purified the enzymes involved in catalyzing the intermediate steps leading to the synthesis of ADP-D-beta-D-heptose and have biochemically characterized the reaction products by high-performance anion-exchange chromatography. We have also constructed a deletion in a novel gene, gmhB (formerly yaeD), which results in the formation of an altered LPS core. This mutation confirms that the GmhB protein is required for the formation of ADP-D-beta-D-heptose. Our results demonstrate that the synthesis of ADP-D-beta-D-heptose in Escherichia coli requires three proteins, GmhA (sedoheptulose 7-phosphate isomerase), HldE (bifunctional D-beta-D-heptose 7-phosphate kinase/D-beta-D-heptose 1-phosphate adenylyltransferase), and GmhB (D,D-heptose 1,7-bisphosphate phosphatase), as well as ATP and the ketose phosphate precursor sedoheptulose 7-phosphate. A previously characterized epimerase, formerly named WaaD (RfaD) and now renamed HldD, completes the pathway to form the ADP-L-beta-D-heptose precursor utilized in the assembly of inner core LPS.

Structural-Functional Studies of Burkholderia cenocepacia D-Glycero-beta-D-manno-heptose 7-Phosphate Kinase (HldA) and Characterization of Inhibitors with Antibiotic Adjuvant and Antivirulence Properties

As an essential constituent of the outer membrane of Gram-negative bacteria, lipopolysaccharide contributes significantly to virulence and antibiotic resistance. The lipopolysaccharide biosynthetic pathway therefore serves as a promising therapeutic target for antivirulence drugs and antibiotic adjuvants. Here we report the structural-functional studies of D-glycero-beta-D-manno-heptose 7-phosphate kinase (HldA), an absolutely conserved enzyme in this pathway, from Burkholderia cenocepacia. HldA is structurally similar to members of the PfkB carbohydrate kinase family and appears to catalyze heptose phosphorylation via an in-line mechanism mediated mainly by a conserved aspartate, Asp270. Moreover, we report the structures of HldA in complex with two potent inhibitors in which both inhibitors adopt a folded conformation and occupy the nucleotide-binding sites. Together, these results provide important insight into the mechanism of HldA-catalyzed heptose phosphorylation and necessary information for further development of HldA inhibitors.