Publications by authors named "Marie-Bernard Lascombe"

Angiogenesis is tightly regulated through the binding of vascular endothelial growth factors (VEGFs) to their receptors (VEGFRs). In this context, we showed that human VEGFR1 domain 2 crystallizes in the presence of Zn2+, Co2+ or Cu2+ as a dimer that forms via metal-ion interactions and interlocked hydrophobic surfaces. SAXS, NMR and size exclusion chromatography analyses confirm the formation of this dimer in solution in the presence of Co2+, Cd2+ or Cu2+.

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Among the different mechanisms used by bacteria to resist antibiotics, active efflux plays a major role. In Gram-negative bacteria, active efflux is carried out by tripartite efflux pumps that form a macromolecular assembly spanning both membranes of the cellular wall. At the outer membrane level, a well-conserved outer membrane factor (OMF) protein acts as an exit duct, but its sequence varies greatly among different species.

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Originally described in bacteria, drug transporters are now recognized as major determinants in antibiotics resistance. For Gram-negative bacteria, the reversible assembly consisting of an inner membrane protein responsible for the active transport, a periplasmic protein, and an exit outer membrane channel achieves transport. The opening of the outer membrane protein OprM from Pseudomonas aeruginosa was modeled through normal mode analysis starting from a new X-ray structure solved at 2.

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Screening of transfer DNA (tDNA) tagged lines of Arabidopsis thaliana for mutants defective in systemic acquired resistance led to the characterization of dir1-1 (defective in induced resistance [systemic acquired resistance, SAR]) mutant. It has been suggested that the protein encoded by the dir1 gene, i.e.

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The structure of sylvaticin, a 10 kDa major pythin protein excreted by the parasitic oomycete Pythium sylvaticum, has been determined. Although closely related to alpha-elicitins in its biological response, toxicity and overall structure, sylvaticin presents a number of structural features that make it an unusual member of the elicitin class. Elicitins possess a large hydrophobic cavity and the mechanism of the systemic acquired resistance induced in planta is known to proceed through lipid transport and complexation within this cavity.

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DIR1, a putative LTP2 protein from Arabidopsis thaliana implicated in systemic acquired resistance in planta, has been crystallized in space group P2(1)2(1)2(1) with one molecule per asymmetric unit. The crystals diffract to a resolution of 1.6 angstroms.

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OprM and OprN belong to the outer membrane factor family proteins. These approximately 52 kDa proteins are part of the tripartite efflux pumps found in Pseudomonas aeruginosa and are responsible in part for the antibiotic resistance observed in these bacteria. Both proteins have been expressed in Escherichia coli as His-tag proteins and purified accordingly by affinity chromatography in the presence of n-octyl-beta-D-glucopyranoside detergent.

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Sylvaticin belongs to the elicitin family. These 10 kDa oomycetous proteins induce a hypersensitive response in plants, including necrosis and cell death, but subsequently leading to a non-specific systemic acquired resistance (SAR) against other pathogens. Sylvaticin has been crystallized using PEG 2000 MME as a precipitant agent in the presence of nickel chloride.

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Cryptogein is a small 10 kDa elicitor produced by the phytoparasitic oomycete Phytophthora cryptogea. The protein also displays a sterol carrier activity. The native protein crystallizes in space group P4(1)22, with unit-cell parameters a = b = 46.

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The crystal structure of Clostridium thermocellum endoglucanase CelA in complex with cellopentaose has been determined at 0.94 A resolution. The oligosaccharide occupies six D-glucosyl-binding subsites, three on either side of the scissile glycosidic linkage.

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