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41.
Etienne Levavasseur Isabelle Laffont-Proust émilie Morain Baptiste A. Faucheux Nicolas Privat Katell Peoc'h Véronique Sazdovitch Jean-Philippe Brandel Jean-Jacques Hauw Stéphane Ha?k 《PloS one》2008,3(7)
Objective
The glycoprofile of pathological prion protein (PrPres) is widely used as a diagnosis marker in Creutzfeldt-Jakob disease (CJD) and is thought to vary in a strain-specific manner. However, that the same glycoprofile of PrPres always accumulates in the whole brain of one individual has been questioned. We aimed to determine whether and how PrPres glycosylation is regulated in the brain of patients with sporadic and variant Creutzfeldt-Jakob disease.Methods
PrPres glycoprofiles in four brain regions from 134 patients with sporadic or variant CJD were analyzed as a function of the genotype at codon 129 of PRNP and the Western blot type of PrPres.Results
The regional distribution of PrPres glycoforms within one individual was heterogeneous in sporadic but not in variant CJD. PrPres glycoforms ratio significantly correlated with the genotype at codon 129 of the prion protein gene and the Western blot type of PrPres in a region-specific manner. In some cases of sCJD, the glycoprofile of thalamic PrPres was undistinguishable from that observed in variant CJD.Interpretation
Regulations leading to variations of PrPres pattern between brain regions in sCJD patients, involving host genotype and Western blot type of PrPres may contribute to the specific brain targeting of prion strains and have direct implications for the diagnosis of the different forms of CJD. 相似文献42.
Paumard P Arselin G Vaillier J Chaignepain S Bathany K Schmitter JM Brèthes D Velours J 《Biochemistry》2002,41(33):10390-10396
Cross-linking experiments showed that the supernumerary subunit i is close to the interface between two ATP synthases. These data were used to demonstrate the presence of ATP synthase dimers in the inner mitochondrial membrane of Saccharomyces cerevisiae. A cysteine residue was introduced into the inter-membrane space located C-terminal part of subunit i. Cross-linking experiments revealed a dimerization of subunit i. This cross-linking occurred only with the dimeric form of the enzyme after incubating intact mitochondria with a bis-maleimide reagent, thus indicating an inter-ATP synthase cross-linking, whereas the monomeric form of the enzyme exhibited only an intra-ATP synthase cross-linking with subunit 6, another component of the membranous domain of the ATP synthase. 相似文献
43.
Petit P Granier T d'Estaintot BL Manigand C Bathany K Schmitter JM Lauvergeat V Hamdi S Gallois B 《Journal of molecular biology》2007,368(5):1345-1357
The nicotinamide adenine dinucleotide phosphate (NADPH)-dependent enzyme dihydroflavonol 4-reductase (DFR) catalyzes a late step in the biosynthesis of anthocyanins and condensed tannins, two flavonoid classes of importance to plant survival and human nutrition. This enzyme has been widely investigated in many plant species, but little is known about its structural and biochemical properties. To provide a basis for detailed structure-function studies, the crystal structure of Vitis vinifera DFR, heterologously expressed in Escherichia coli, has been determined at 1.8 Å resolution. The 3D structure of the ternary complex obtained with the oxidized form of nicotinamide adenine dinucleotide phosphate and dihydroquercetin, one of the DFR substrates, presents common features with the short-chain dehydrogenase/reductase family, i.e., an N-terminal domain adopting a Rossmann fold and a variable C-terminal domain, which participates in substrate binding. The structure confirms the importance of the 131-156 region, which lines the substrate binding site and enlightens the role of a specific residue at position 133 (Asn or Asp), assumed to control substrate recognition. The activity of the wild-type enzyme and its variant N133D has been quantified in vitro, using dihydroquercetin or dihydrokaempferol. Our results demonstrate that position 133 cannot be solely responsible for the recognition of the B-ring hydroxylation pattern of dihydroflavonols. 相似文献
44.
Insights into the role of specific lipids in the formation and delivery of lipid microdomains to the plasma membrane of plant cells 总被引:1,自引:0,他引:1 下载免费PDF全文
Laloi M Perret AM Chatre L Melser S Cantrel C Vaultier MN Zachowski A Bathany K Schmitter JM Vallet M Lessire R Hartmann MA Moreau P 《Plant physiology》2007,143(1):461-472
The existence of sphingolipid- and sterol-enriched microdomains, known as lipid rafts, in the plasma membrane (PM) of eukaryotic cells is well documented. To obtain more insight into the lipid molecular species required for the formation of microdomains in plants, we have isolated detergent (Triton X-100)-resistant membranes (DRMs) from the PM of Arabidopsis (Arabidopsis thaliana) and leek (Allium porrum) seedlings as well as from Arabidopsis cell cultures. Here, we show that all DRM preparations are enriched in sterols, sterylglucosides, and glucosylceramides (GluCer) and depleted in glycerophospholipids. The GluCer of DRMs from leek seedlings contain hydroxypalmitic acid. We investigated the role of sterols in DRM formation along the secretory pathway in leek seedlings. We present evidence for the presence of DRMs in both the PM and the Golgi apparatus but not in the endoplasmic reticulum. In leek seedlings treated with fenpropimorph, a sterol biosynthesis inhibitor, the usual Delta(5)-sterols are replaced by 9beta,19-cyclopropylsterols. In these plants, sterols and hydroxypalmitic acid-containing GluCer do not reach the PM, and most DRMs are recovered from the Golgi apparatus, indicating that Delta(5)-sterols and GluCer play a crucial role in lipid microdomain formation and delivery to the PM. In addition, DRM formation in Arabidopsis cells is shown to depend on the unsaturation degree of fatty acyl chains as evidenced by the dramatic decrease in the amount of DRMs prepared from the Arabidopsis mutants, fad2 and Fad3+, affected in their fatty acid desaturases. 相似文献
45.
Bac Alain Rivoal Katell Cung Manh Thong Boussard Guy Marraud Michel Soudan Benoît Tetaert Daniel Degand Pierre 《International journal of peptide research and therapeutics》1997,4(4-6):251-258
Summary Consequences inherent to the substitution of aza-proline (AzPro) for proline in the octapeptide TTSAPTTS, representative of
the tandem repeat motif present in the peptide backbone of MUC5AC mucin, were analysed in terms of conformational perturbation
and O-glycosylation aptitude. In DMSO solution, we observed the same tendency previously noted in AzPro-tripeptide models,
i.e. AzPro prevents β-turn formation in which it would occupy the i+1 position, and therefore behaves quite opposite to Pro,
whereas both AzPro and Pro can support a β-turn in the i+2 position with a cis disposition of the preceding tertiary amide
function. The former structural modifications do not prevent O-glycosylation to take place at the same specific site, but
it occurs at a reduced rate. 相似文献