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PubMed1994

The complete amino acid sequence and disulphide bond arrangement of oat alcohol-soluble avenin-3.

We have elucidated the complete amino acid sequence of one of the avenin components, avenin-3, isolated from oat (Avena sativa L.), variety Narymsky 943. The sequence of the protein was determined by sequencing of CNBr and trypsin-generated peptides in combination with mass spectrometry. The protein is a single polypeptide chain, consisting of 201 amino acid residues with M(r) 23,252.8. The N-terminal amino acid residue of the protein is blocked with 5-oxoproline (pyroglutamic acid). All eight cysteine residues in avenin-3 are involved in disulphide bonds. The positions of these bonds were established by identification of a CNBr cleavage product of the intact avenin containing all the disulfide bonds (S-S core). Subsequent subdigestion of this S-S core allowed isolation of disulphide bonded peptides detected by differential reverse-phase HPLC before and after reduction. As a result, all four disulphides Cys50 Cys183, Cys58 Cys77, Cys84 Cys85 and Cys97 Cys191 were identified. Comparison of avenins with other prolamins demonstrates a high degree of similarity, which is especially pronounced around the cysteine residues. Avenins differ slightly from other prolamins in having unique N-terminal sequences and some differences in the repeated sequence motifs.

Amino Acid Sequence↗

PubMedDate not supplied

Characterization of low-molecular-weight glutenin subunit genes from Hordeum brevisubulatum ssp. turkestanicum.

Three novel low-molecular-weight glutenin subunit (LMW-GS) genes (designated as Ht1, Ht2, and Ht3) were isolated from the genomic DNA of Hordeum brevisubulatum ssp. turkestanicum by PCR amplification (accession no. Y0695). The coding regions of Ht1, Ht2, and Ht3 were 924, 924, and 903 bp, respectively. The deduced amino acid sequences were 306, 306, and 299 amino acid residues each with a signal peptide, a central repetitive region rich in proline and glutamine, and N- and C-terminal non-repetitive domains. A comparison was carried out of these genes with other known B hordein genes from cultivated barley and LMW glutenin genes from wheat. The results indicated that Ht1, Ht2, and Ht3 had a more similar structure and a higher level of homology with the LMW-GS genes than the B hordein genes. In order to investigate the evolutionary relationship of the novel genes with the prolamin genes from barley and wheat, the phylogenetic tree was constructed and the subfamilies of these prolamin genes were identified. The results suggested that the three novel genes were glutenin-like proteins designated as LMW-m type genes.

Amino Acid Sequence↗

PubMed2003

Studies on the amino acid and mineral content of buckwheat protein fractions.

Protein fractions were extracted by successive extraction and analysis method in four buckwheat varieties including Japanese spring buckwheat, Japanese summer buckwheat, Yuqiao No. 1 and Yuqiao 6-21. The amino acid and the mineral content of each protein fraction were also analyzed in this paper. The basis for the data on the experiment was the relationship between protein fractions and amino acids, and the mineral contents of protein fractions. The distribution and proportion of amino acids and the minerals in each protein fraction in the buckwheat kernel as well as the nutritional value of buckwheat kernel were discussed. The results showed that there is a high amount of soluble protein and very low amount of prolamin in the buckwheat kernel. Leucine is the first limited amino acid in buckwheat, and buckwheat protein is only a seminutritional protein. The buckwheat kernel is rich in K, Zn in the albumin, Ca, Mg and Mn in the globulin, Na in the prolamin and glutelin.

Amino Acids↗

PubMed2003

Molecular modeling of various peptide sequences of gliadins and low-molecular-weight glutenin subunits.

The contribution of the three-dimensional structures of one heptapeptide (PQPQPFP) sequence and one pentapeptide (PQQPY) repeat sequence of alpha/beta-gliadins, one heptapeptide (PQQPFPQ) repeat sequence of gamma-gliadins, two heptapeptide (PQQPPFS and QQQQPVL) repeat motifs of low-molecular-weight (LMW) subunits and a tetrapeptide sequence in polyQ region of S-rich prolamins to their conformations are investigated by using the recently developed multicanonical simulation procedure. Ramachandran plots were prepared and analysed to predict the relative occurrence probabilities of gamma-tutn, gamma-turn, and helical structures. The probability of inverse 7-turn was generally higher than that of beta-turns in all sequences investigated. Occurrence probability of helical structure in the repetitive domain of gliadins was low. Structural predictions of QQQQPVL sequence of LMW-glutenin subunits and QQQQ sequence in the polyQ region of S-rich prolamins indicate the presence of helical structures with the probability of >20%. The probability of helical structure significantly decreased around 100 degrees C.

Amino Acid Sequence↗

PubMed1992

Cloning and characterization of a cDNA encoding a sulfur-rich coixin.

A full-length cDNA clone encoding a sulfur-rich Coix prolamin was isolated using a cDNA library constructed from polysomal mRNA prepared from immature Coix endosperm. The deduced amino acid sequence of the cDNA clone predicted a polypeptide of 194 residues, which shared 64% homology with the 17 kDa beta-zein. The mature protein contains the familiar composition of the prolamins and an unusually high content of the sulfur-containing amino acids methionine (11.6%) and cysteine (5.2%). In vitro transcription followed by in vitro translation of the coding region of the pBCX17.9S clone gave rise to a polypeptide with an apparent molecular weight corresponding to the C4 alpha-coixin. Hydropathy analysis showed that C4 alpha-coixin is slightly more hydrophobic than beta-zein.

Amino Acid Sequence↗

PubMed1995

Analysis of randomly isolated cDNAs from developing endosperm of rice (Oryza sativa L.): evaluation of expressed sequence tags, and expression levels of mRNAs.

Using a cDNA library prepared from poly(A)+ RNA from 10-day-old rice endosperm, partial nucleotide sequences of randomly isolated clones were analyzed. A total of 153 (30.6%) out of 500 cDNA clones showed high amino acid identity to previously identified genes. There was significant redundancy in cDNAs encoding prolamine and glutelin. About 21.0% of the cDNA clones were found to code for seed storage protein genes. Consequently, 37 independent genes were identified. Using cDNA clones encoding glutelin, prolamine, seed allergen, alpha-1,4-glucan branching enzyme, glycine-rich RNA binding protein, metallothionein, non-specific lipid-transfer protein and ubiquitin conjugating enzyme the accumulation of mRNA during rice seed development was compared. Genes associated with seed storage protein and starch biosynthesis were expressed according to expected developmental stages. Glycine-rich RNA binding protein genes as well as metallothionein-like protein genes were highly expressed in developing seeds, but low in leaves of whole plants.

Blotting, Northern↗

PubMed1994

Structural characterization and promoter activity analysis of the gamma-kafirin gene from sorghum.

A genomic clone encoding the gamma-kafirin gene from sorghum was isolated and sequenced. A 2938 bp sequenced fragment includes an intronless open reading frame of 636 nucleotides encoding a putative polypeptide of 212 amino acids. Comparison of the deduced amino acid sequence of gamma-kafirin with the published sequences of gamma-prolamins of maize, and Coix revealed highly conserved domains. The N-terminal region of these proteins contains the conserved hexapeptide PPPVHL, which is repeated eight times in gamma-zein, four times in gamma-kafirin and three times in gamma-coixin. The number of PPPVHL repeats accounts predominantly for the differences in the molecular weights of gamma-prolamins. Several putative regulatory sequences common to the gamma-kafirin and gamma-zein genes were identified in both the 5' and the 3' flanking regions. Putative GCN4-like regulatory sequences were found at positions -192 and -476 in the 5' flanking region of gamma-kafirin. In the 3' noncoding region, three putative polyadenylation signals, two AATAAT and one AATGAA, were found at positions +658, +716, and +785, respectively. In order to investigate the role of the putative GCN4-like motifs and other possible cis-acting element(s) of the gamma-kafirin promoter, a series of deleted and chimeric promoter constructs were introduced into maize, Coix and sorghum tissues by particle bombardment. Histochemical analysis of beta-glucuronidase (GUS) activity in different tissues indicated that the element(s) responsible for tissue specificity is probably located in the 285-bp proximal region of the promoter, while the remaining promoter sequence seems to carry the element(s) responsible for the quantitative response.

Amino Acid Sequence↗

PubMed1995

Amaranth seed proteins: effect of defatting on extraction yield and on electrophoretic patterns.

Acetone and hexane were used to know the effect of defatting amaranth flour on the extraction yield of protein fractions and on the electrophoretic patterns. It was found that albumins (33%) and globulins (20%) did not present yield changes when using these two solvents, but it was noted that with hexane compared to acetone, prolamins extraction was reduced by half (3.0 to 1.6%) whereas glutelins increased from 26.5 to 30%. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns of prolamins extracted with acetone and hexane showed one band of low molecular weight (22 KDa) and five bands between 52 to 22 KDa, respectively. No electrophoretic changes were observed in the remaining fractions.

Acetone↗

PubMed1988

Characterization of seed storage proteins of urdbean (Vigna mungo).

Dehulled and defatted flour of urdbean (Vigna mungo), Var T-9, contained 25% protein with maximum contribution by globulins (63%). Albumins and glutelins contributed 12% and 21% respectively, whereas prolamins were present only in traces (1%). Globulins were further fractionated into legumin and vicilin type proteins which were present in the ratio of 4:1. All the protein fractions were heterogenous in nature as revealed by high performance liquid chromatography. SDS-polyacrylamide gel electrophoresis revealed the total protein sample to contain 21 different components with molecular weights ranging from 8.92 to 117.49 kd. Albumins, globulins, prolamins and glutelins resolved into 4, 8, 6 and 13 different sized components of molecular weights ranging from 10.23 to 25.53, 10.84 to 112.72, 10.33 to 51.52 and 8.91 to 112.72 kd, respectively. Amino acid analysis of all fractions revealed that glutamic acid was present in maximum concentration followed by aspartic acid and lysine. Just like other pulse proteins, the urdbean proteins were also deficient in sulphur containing amino acids.

Albumins↗

PubMed1983

[Functional evaluation of islet cells following pancreatic duct occlusion--a long-term study].

The transduodenal occlusion of the pancreatic duct with Prolamin (Ethibloc) was carried out in an experiment with 38 Göttinger minipigs. Occlusion of the pancreatic duct leads to selective atrophy of the excretory pancreatic parenchyma. Up until now it has not been clear whether the endocrine functional capacity of the gland stays intact in a long-term experiment or whether the islands of Langerhans are also altered by the pancreatic duct occlusion. The following tests were carried out by us to determine the endocrine status: 1. Intravenous glucose tolerance test (i.v. GTT); 2. Glucose assimilation analysis after CONARD (K-value); 3. Insulin analysis during i.v. GTT; 4. Intravenous Tolbutamid test. Twelve months after the occlusion, reduced glucose tolerance and a reduction in insulin secretion were detected in the intravenous glucose tolerance test. Glucose assimilation (K-value) was not changed significantly. Fasting blood sugar and basic insulin level remained unchanged. Only a small blood-sugar decrease was measured after selective B-cell stimulation with Tolbutamid. The fibrosclerosis produced by the occlusion of the pancreatic duct with Prolamin also seemed to attack the cells of the islands and lead to their partial destruction.

Animals↗

PubMed1989

[Insulin reserve and morphology of the tail of the pancreas following resection of the head of the pancreas using various surgical methods].

Four modifications of dealing surgically with the remaining pancreas after resection of the pancreatic head were compared to each other in dogs. Insulin response and corresponding blood sugar levels were controlled, the remaining pancreas was examined histologically. The obstruction of the pancreatic ducts by prolamine showed mainly sclerosis of the exocrine tissue whereas the duct ligation was followed by atrophy. The free intraperitoneal draining of the duct system showed both alterations, the pancreatojejunostomy did hardly impair the exocrine pancreas. According to the grade of sclerosis of the exocrine tissue, the insulin response was delayed followed by a pathologic glucose tolerance. This was shown particularly for the obstruction of the ducts by prolamine.

Amylases↗

PubMed1995

Molecular flexibility in wheat gluten proteins submitted to heating.

Prolamin proteins are responsible for the network that gives wheat dough its viscoelastic properties. Non-prolamin depleted gluten was prepared under conditions that preserve its functionality. Electron Spin Resonance (ESR) was used to provide information about the dynamics of the protein at temperatures between 5 and 90 degrees C by specific spin labelling of its cysteine residues. The spectra were of a composite type, resulting from at least two populations of spin labels largely differing in molecular mobility. The correlation time of the less mobile nitroxide radicals was determined by saturation transfer ESR. Upon heating there was a transfer from the slow to the fast moving population of radicals, and an increase of mobility of this last catagory that followed the Arrhenius law. The effect of temperature on molecular flexibility was reversible. This was not the case for purified, polymerised glutenin subunits extracted from gluten. Urea created similar modifications on gluten as heat.

Electron Spin Resonance Spectroscopy↗

PubMed1990

Comparison of graft morphology and endocrine function after vascularized whole-pancrease transplantation in the rat by different surgical techniques.

Graft morphology and endocrine function following vascularized pancreas transplantation by different surgical techniques were determined in streptozotocin-diabetic rats. Eight different surgical techniques were studied. Intestinal drainage of exocrine secretion was accomplished by pancreaticoduodenal transplantation or by utilizing only a patch of the donor duodenum for duodenojejunostomy. Following pancreaticoureterostomy and pancreaticocystostomy, the graft's exocrine secretion was drained to the recipient's urinary tract. The exocrine secretion was allowed to drain freely into the recipient's peritoneal cavity following transverse or longitudinal incision of the common bile duct. Exocrine secretion was suppressed either by duct ligation or by retrograde ductal injection of prolamine. Following enteric or urinary exocrine graft drainage, the architecture of both the endocrine and exocrine pancreas was perfectly preserved. Pancreatic juice had remarkably few adverse effects on the recipient's urinary tract. Obstruction of the exocrine secretion induced atrophy of the acinar cells, proliferation of small pancreatic ducts, and a typical fragmentation of the islets of Langerhans. Prolamine was biologically degraded within 28 days. Following free intraperitoneal drainage, spontaneous suppression of the exocrine graft function occurred early after transplantation. Metabolic signs of diabetes mellitus including hypoinsulinemia, hyperglycemia, polydipsia, polyuria, and impaired glucose tolerance were completely normalized by pancreas transplantation irrespective of the surgical technique used. Despite fundamental differences in graft architecture no alteration of endocrine graft function was noted following vascularized pancreas transplantation by different surgical techniques.

Animals↗

PubMed2005

Plant food allergens--structural and functional aspects of allergenicity.

The three dominating plant food allergen groups belong to the prolamin and cupin superfamilies and to the family 10 of pathogenesis-related proteins. The prolamin superfamily comprises allergenic 2S albumins, nonspecific lipid transfer proteins and cereal alpha-amylase/trypsin inhibitors. These allergens have related structures and are stable to thermal processing and proteolysis. The cupin superfamily comprises the allergenic 7S and 11S globulin storage proteins from peanuts, soybean and tree nuts which are heat stable and can form immunogenicity enhancing aggregates. The Bet v 1 family of allergens includes tree pollinosis-associated food allergens with low stability which induce the symptoms of the oral allergy syndrome.

Allergens↗

PubMed2001

Uptake and distribution of rare earth elements in rice seeds cultured in fertilizer solution of rare earth elements.

The uptake behavior of rare earth elements (REEs) under pot conditions using deionized water and a REE fertilizer solution as the culture media as well as the distribution of REEs in rice proteins were studied. The uptake of REEs in rice seeds increased dramatically after a lag period of approximately three days. Roots can accumulate a much higher content of REEs than germs and the resting seeds. The REE content in each water-soluble (albumin) and salt-soluble (globulin) component of the rice seeds accounted for 5-8% and 4-6% of the total REEs, respectively. However, there are less than 1.5% of the total REEs were found in the alcohol-soluble (prolamin) and acetic acid-soluble (glutelin) components. The high performance liquid chromatography (HPLC) in the gel permeation and the reserved-phase were used to monitor changes in the molecular weight distribution changes of the soluble proteins of rice seeds during germination after having been cultured in the same solution for seven days. No changes occurred in the prolamin, while a slight change occurred in the albumin, globulin and glutelin. Fractionation of the albumin of rice seeds cultured in a REE fertilizer solution on the Sephadex G-100 column indicated that REEs, especially Ce, La, Pr and Nd, were associated mainly with biological compounds of a molecular weight between 10,000 and 12,000.

Absorption↗

PubMed2003

Distribution of storage proteins in low-glutelin rice seed determined using a fluorescent antibody.

To compare the distribution of storage proteins in low-glutelin rice seed with that in other cultivars having normal protein compositions, immunofluorescence labeling with specific antibodies was applied to visualize the distribution of storage proteins in endosperm tissues. The endosperm tissues from five cultivars were reacted with anti-prolamin and anti-glutelin antibodies, and then observed by light microscopy and confocal laser scanning microscopy (CLSM). In low-glutelin rice, using microscopic analysis, a large proportion of storage proteins was observed in the endosperm tissue of 70% polished rice. To determine the localization of two types of protein bodies in endosperm tissues, images of the distribution of the type I protein body (PB-I) and the type II protein body (PB-II) were obtained by CLSM. The CLSM images showed that, in low-glutelin rice, prolamin which accumulates in PB-I remains in the center of 70% polished rice grains despite the elimination of 30% of the outer layer of brown rice grains. However, the other cultivars mostly contained glutelin which accumulates in PB-II and is distributed throughout the endosperm tissues. This shows that low-glutelin rice differs from the other cultivars not only in the major storage protein composition but also in the distribution of storage proteins in endosperm tissues.

Journal Article↗

PubMed2004

Solution structure and stability against digestion of rproBnIb, a recombinant 2S albumin from rapeseed: relationship to its allergenic properties.

NMR spectroscopy has been used to determine the solution structure of the precursor form of the recombinant napin BnIb, rproBnIb, a 2S albumin, 109-residue protein from the seeds of Brassica napus. More than 90% of the side-chain proton resonances were unambiguously assigned from the analysis of two-dimensional correlation (COSY), total correlation (TOCSY), and nuclear Overhauser effect (NOESY) spectra. The final structures were computed by using restrained molecular dynamics on the basis of 1316 upper-limit distance constraints derived from NOE cross-correlation intensities. The computed structures exhibited a root-mean-square deviation (RMSD) radius of 0.66 A for the backbone and 1.16 A for the side-chain heavy atoms of the structural core. The resulting structure consists of five amphipathic helices arranged in a right-handed super helix, a folding motif found in other proteins of the prolamin superfamily. As in the case of the mature protein, the recombinant precursor behaves as a plant food allergen. To trace out the origin and characteristics of its allergenic properties, rproBnIb was assayed against simulated gastric fluid and found to be very resistant to proteolysis. Also, heat treatment of the protein followed up to 85 degrees C by circular dichroism showed a very limited unfolding, which was recovered after cooling to 20 degrees C, indicating a high thermal stability. These results suggest that rproBnIb, as other 2S albumins, may be able to reach the gut immune system intact. A comparison of the putative epitopes against IgE antibodies of the three members of the prolamine family [2S albumins, nonspecific lipid transfer proteins (nsLTPs), and alpha-amylase/trypsin inhibitors] indicates that there are not common surfaces of interaction with IgE. Though the epitopes appear to be located in different regions of the proteins, they do comply with the requirements of being solvent-exposed and flexible.

2S Albumins, Plant↗

PubMed2001

Characterization of yam bean (Pachyrhizus erosus) proteins.

Seed proteins from Mexican yam bean seeds (Pachyrhizus erosus L.) were sequentially extracted according to the Osborne classification. Albumins were the major fraction (52.1-31.0%), followed by globulins (30.7-27.5%). The minor protein fraction was prolamins (0.8%). Defatting with chloroform/methanol remarkably affected the distribution of protein solubility classes; albumins were the most affected fraction (4.3-17.5%). Electrophoretic patterns of albumins showed bands at 55, 40, 35, and 31 kDa. After reduction of the globulin fraction exhibited two triplets, one from 35 to 31 kDa and the second from 19 to 21 kDa, these could be compared to the acid and basic polypeptides of 11S-like proteins. Prolamins showed one band at 31 kDa, and glutelins after reduction showed three main bands at 52, 27, and 14 kDa. Trypsin inhibitors were assayed in saline extracts; the values found (1232-2608 IU/g of meal) were lower than those of other legumes. In general, yam bean seed proteins showed an excellent balance of all essential amino acids; albumins contain the highest amount of essential amino acids.

Albumins↗