A new distinct group of 2 S albumins from rapeseed. Amino acid sequence of two low molecular weight napins.
(17/59)
Two napins (nIa and nIb), isolated from Brassica napus (rapeseed) seeds, have been sequenced. The two proteins show the common structural pattern of the 2 S albumins, since they are composed of two disulfide-linked chains of different size, yet they exhibit an atypical low molecular weight (12.5 kDa vs. 14.5 kDa of the major napins). High sequence similarity has been found between these 2 proteins, but only 54% similarity can be estimated from their comparison with the 14.5 kDa major napins. Thus, nIa and nIb are considered representatives of a new distinct group of rapeseed napins since all the previously known napins exhibit 95% sequence similarity. Unexpectedly, the similarity increases when compared with the 2 S proteins from other species. (+info)
In situ localization of storage protein mRNAs in developing meristems of Brassica napus embryos.
(18/59)
Probes derived from cDNA clones of napin and cruciferin, the major storage proteins of Brassica napus, and in situ hybridization techniques were used to examine changes in the spatial and temporal distribution of storage protein messages during the course of embryogeny, with a special emphasis on the developing apical meristems. Napin mRNAs begin to accumulate in the cortex of the axis during late heart stage, in the outer faces of the cotyledons during torpedo stage and in the inner faces of the cotyledons during cotyledon stage. Cruciferin mRNAs accumulate in a similar pattern but approximately 5 days later. Cells in the apical regions where root and shoot meristems develop do not accumulate storage protein messages during early stages of embryogeny. In the upper axis, the boundary between these apical cells and immediately adjacent cells that accumulate napin and cruciferin mRNAs is particularly distinct. Our analysis indicates that this boundary is not related to differences in tissue or cell type, but appears instead to be coincident with the site of a particular set of early cell divisions. A major change in the mRNA accumulation patterns occurs halfway through embryogeny, as the embryos enter maturation stage and start drying down. Final maturation of the shoot apical meristem is associated with the development of leaf primordia and the accumulation of napin mRNAs in the meristem, associated leaf primordia and vascular tissue. Cruciferin mRNAs accumulate only in certain zones of the shoot apical meristem and on the flanks of leaf primordia. Neither type of mRNA accumulates in the root apical meristem at any stage. (+info)
Effector activity of peanut allergens: a critical role for Ara h 2, Ara h 6, and their variants.
(19/59)
A pivotal role of the basic leucine zipper transcription factor bZIP53 in the regulation of Arabidopsis seed maturation gene expression based on heterodimerization and protein complex formation.
(20/59)
Immunoglobulin E cross-reactivity between lupine conglutins and peanut allergens in serum of lupine-allergic individuals.
(21/59)
BACKGROUND: Lupine is used increasingly in food products. The development of lupine allergy in peanut-allergic patients is believed to occur as a result of cross-reactivity between lupine and peanut proteins. OBJECTIVE: To investigate the degree of immunoglobulin (Ig) E cross-reactivity between allergens in lupine and peanut. METHODS: We investigated IgE cross-reactivity between lupine alpha-, beta-, gamma-, and delta-conglutins and the major peanut allergens Ara h 1, Ara h 2 and Ara h 3 using enzyme-linked immunosorbent assay with sera from patients with coexisting peanut and lupine allergy. RESULTS: Peanut proteins inhibited IgE binding towards alpha- conglutins, delta-conglutins, and, to a lesser degree, beta-conglutins, while no IgE cross-reaction with delta-conglutin was observed. Ara h 2 most potently inhibited IgE binding to lupine and delta-conglutins, while Ara h 1 most potently cross-reacted with beta-conglutin. Ara h 3 was apparently not involved in these mechanisms. CONCLUSIONS: The present study reveals IgE cross-reactivity between the 2S albumins Ara h 2 and delta-conglutin, and the 7S vicilin-like Ara h 1 and beta-conglutin, which are possibly based on homologies between phylogenetically related proteins. Ara h 2 was the most potent inhibitor of IgE binding to lupine conglutins. (+info)
Primary sequence and site-selective hydroxylation of prolines in isoforms of a major peanut allergen protein Ara h 2.
(22/59)
Amino acid and cDNA sequences of a methionine-rich 2S protein from sunflower seed (Helianthus annuus L.).
(23/59)
The amino acid sequence of a methionine-rich 2S seed protein from sunflower (Helianthus annuus L.) and the sequence of a cDNA clone which codes for the entire primary translation product have been determined. The mature protein consists of a single polypeptide chain of 103 amino acids (molecular mass 12133 Da) which contains 16 residues of methionine and 8 residues of cysteine. The cDNA sequence established that the protein is synthesized as a precursor of 141 residues with a typical hydrophobic signal sequence of 25 residues followed by a further 13-residue hydrophobic pro-sequence which is presumably removed by post-translational cleavage. The sequence of the mature protein and that deduced from the cDNA were identical with no evidence of processing at the C-terminus. Comparison of the sunflower methionine-rich protein sequence with sequences of other seed 2S proteins from dicotyledons and monocotyledons showed limited but distinct sequence similarities; in particular the arrangement of the cysteine residues was conserved. The sunflower protein shows 34% identity with the methionine-rich Brazil nut 2S protein and the prepro regions of the precursors of these two proteins show about 50% identity. This similarity indicates that these methionine-rich 2S proteins have diverged as a subclass of the 2S superfamily of proteins which contain only 2-3% methionine. While the related 2S proteins from other dicotyledons are processed to a small and large subunit, the sunflower protein is not cleaved in this way. (+info)
Analysis of the promoter region of napin genes from Brassica napus demonstrates binding of nuclear protein in vitro to a conserved sequence motif.
(24/59)
Napin is a seed storage protein from Brassica napus (rape) that is encoded by a gene family. We have isolated and characterized a novel napin gene, napB. Comparisons of the 5'-upstream region of napB to the promoter regions of previously published napin genes reveal that certain sequence motives are evolutionary conserved and may be implicated in gene regulation. These consensus motives, that overlap with purine/pyrimidine stretches, are TACACAT and CATGCA both of which frequently occur as overlapping, direct repeats. Related or identical sequences are also found in the upstream regions of the homologous genes of Arabidopsis thaliana. One copy of the CATGCA motif occurs in close proximity to the TATA box in all the above genes. In this case it overlaps with an octamer sequence (ATGCAAAT) which is a sequence element common in many eukaryotic promoters and enhancers. The TACACAT sequence, as part of a longer purine/pyrimidine stretch, was found to interact with a protein present in crude nuclear extracts from developing B. napus seeds. Napin genes appear to be methylated to almost equal extents whether present in expressing or non-expressing tissue. (+info)