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81.
Production of tailor-made fructans in sugar beet by expression of onion fructosyltransferase genes 总被引:3,自引:0,他引:3
Weyens G Ritsema T Van Dun K Meyer D Lommel M Lathouwers J Rosquin I Denys P Tossens A Nijs M Turk S Gerrits N Bink S Walraven B Lefèbvre M Smeekens S 《Plant biotechnology journal》2004,2(4):321-327
The consumption of fructans as a low caloric food ingredient or dietary fibre is rapidly increasing due to health benefits. Presently, the most important fructan source is chicory, but these fructans have a simple linear structure and are prone to degradation. Additional sources of high-quality tailor-made fructans would provide novel opportunities for their use as food ingredients. Sugar beet is a highly productive crop that does not normally synthesize fructans. We have introduced specific onion fructosyltransferases into sugar beet. This resulted in an efficient conversion of sucrose into complex, onion-type fructans, without the loss of storage carbohydrate content. 相似文献
82.
Gianfrani C Troncone R Mugione P Cosentini E De Pascale M Faruolo C Senger S Terrazzano G Southwood S Auricchio S Sette A 《Journal of immunology (Baltimore, Md. : 1950)》2003,170(5):2719-2726
One of the diagnostic hallmarks of the histological lesions associated with celiac disease is the extensive infiltration of the small intestinal epithelium by CD8(+) T cells of unknown Ag specificity. In this study, we report recognition of the gliadin-derived peptide (A-gliadin 123-132) by CD8(+) T lymphocytes from celiac patients. A-gliadin 123-132-specific IFN-gamma production and cytotoxic activity were detected in PBMCs derived from patients on gluten-free diet, but not from either celiac patients on gluten-containing diet or healthy controls. In contrast, A-gliadin 123-132-specific cells were isolated from small intestine biopsies of patients on either gluten-free or gluten-containing diets. Short-term T cell lines derived from the small intestinal mucosa and specific for the 123-132 epitope recognized human APC pulsed with either whole recombinant alpha-gliadin or a partial pepsin-trypsin gliadin digest. Finally, we speculate on a possible mechanism leading to processing and presentation of class I-restricted gliadin-derived epitopes in celiac disease patients. 相似文献
83.
Evidence for packaging of rep-cap sequences into adeno-associated virus (AAV) type 2 capsids in the absence of inverted terminal repeats: a model for generation of rep-positive AAV particles 下载免费PDF全文
We previously reported that a 350-bp region of the adeno-associated virus (AAV) type 2 rep gene contains a cis-acting element responsible for the Rep-dependent replication of a transiently transfected rep-cap plasmid. In this study, we further report that replicated rep-cap sequences can be packaged into AAV capsids in the absence of the inverted terminal repeats. 相似文献
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Trivelli X Krimm I Ebel C Verdoucq L Prouzet-Mauléon V Chartier Y Tsan P Lauquin G Meyer Y Lancelin JM 《Biochemistry》2003,42(48):14139-14149
Peroxiredoxins (Prx's) are a superfamily of thiol-specific antioxidant proteins present in all organisms and involved in the hydroperoxide detoxification of the cell. The catalytic cysteine of Prx's reduces hydroperoxides and is transformed into a transient sulfenic acid (Cys-SOH). At high hydroperoxide concentration, the sulfenic acid can be overoxidized into a sulfinate, or even a sulfonate. We present here the first peroxiredoxin characterization by solution NMR of the Saccharomyces cerevisiae alkylhydroperoxide reductase (Ahp1) in its reduced and in vitro overoxidized forms. NMR (15)N relaxation data and ultracentrifugation experiments indicate that the protein behaves principally as a homodimer (2 x 19 kDa) in solution, regardless of the redox state. In vitro treatment of Ahp1 by a large excess of tBuOOH leads to an inactive form, with the catalytic cysteine overoxidized into sulfonate, as demonstrated by (13)C NMR. Depending on the amino acid sequence of their active site, Prx's are classified into five different families. In this classification, Ahp1 is a member of the scarcely studied D-type Prx's. Ahp1 is unique among the D-type Prx's in its ability to form an intermolecular disulfide. The peptidic sequence of Ahp1 was analyzed and compared to other D-type Prx sequences. 相似文献
86.
Schütz M Schoepp-Cothenet B Lojou E Woodstra M Lexa D Tron P Dolla A Durand MC Stetter KO Baymann F 《Biochemistry》2003,42(36):10800-10808
Phylogenetic analysis of constituent proteins of Rieske/cytochrome b complexes [Schütz et al. (2000) J. Mol. Biol. 300, 663-675] indicated that the respective enzyme from the hyperthermophile Aquifex (A.) aeolicus is closely related to proteobacterial counterparts, in disagreement with positioning of its parent species on small subunit rRNA trees. An assessment of the details and possible reasons for this discrepancy necessitates a thorough understanding of the biochemical and biophysical properties of the enzyme in addition to the bioinformatic data. The cytochrome bc(1) complex from A. aeolicus, which is part of the "Knallgasreaction" pathway, was therefore studied in membranes and in detergent-solubilized, isolated complex. Hemes b(L) (E(m,7) = -190 mV; g(z)= 3.7), b(H) (E(m,7) = -60 mV; g(z )= 3.45), and c(1) (E(m,7) = +160 mV; g(z )= 3.55) were identified by EPR and optical spectroscopy in combination with electrochemical methods. Two electrochemically distinct (E(m,7) = +95 mV; E(m,7) = +210 mV) Rieske centers were detected in membranes, and the +210 mV species was shown to correspond to the Rieske center of the cyt bc(1) complex. The gene coding for this latter Rieske protein was heterologously expressed in Escherichia coli, and the resulting protein was characterized in detail. The pool quinone of A. aeolicus was determined to be naphthoquinone. The redox poises of the individual electron-transfer steps are compared to those of other Rieske/cyt b complexes. The Aquifex enzyme was found to represent the only extant naphthoquinol oxidizing true cyt bc(1) complex described so far. An improved scenario for the phylogenetic positioning of the Aquifex cyt bc(1) complex is proposed. 相似文献
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InlB, a surface-localized protein of Listeria monocytogenes, induces phagocytosis in non-phagocytic mammalian cells by activating Met, a receptor tyrosine kinase. InlB also binds glycosaminoglycans and the protein gC1q-R, two additional host ligands implicated in invasion. We present the structure of InlB, revealing a highly elongated molecule with leucine-rich repeats that bind Met at one end, and GW domains that dissociably bind the bacterial surface at the other. Surprisingly, the GW domains are seen to resemble SH3 domains. Despite this, GW domains are unlikely to act as functional mimics of SH3 domains since their potential proline-binding sites are blocked or destroyed. However, we do show that the GW domains, in addition to binding glycosaminoglycans, bind gC1q-R specifically, and that this binding requires release of InlB from the bacterial surface. Dissociable attachment to the bacterial surface via the GW domains may be responsible for restricting Met activation to a small, localized area of the host cell and for coupling InlB-induced host membrane dynamics with bacterial proximity during invasion. 相似文献
90.