scholarly journals Biosynthesis of Arabinogalactan-Protein in Lolium multiflorum (Ryegrass) Endosperm Cells

1983 ◽  
Vol 72 (3) ◽  
pp. 754-758 ◽  
Author(s):  
Peter B. Cohen ◽  
Angelo Schibeci ◽  
Geoffrey B. Fincher
Keyword(s):  
Lolium Multiflorum ◽  
Arabinogalactan Protein

scholarly journals Characterization of the hydroxyproline-rich protein core of an arabinogalactan-protein secreted from suspension-cultured Lolium multiflorum (Italian ryegrass) endosperm cells

1989 ◽  
Vol 264 (3) ◽  
pp. 857-862 ◽  
Author(s):  
P A Gleeson ◽  
M McNamara ◽  
R E H Wettenhall ◽  
B A Stone ◽  
G B Fincher
Keyword(s):  
Polyclonal Antibodies ◽  
Lolium Multiflorum ◽  
Italian Ryegrass ◽  
Arabinogalactan Protein ◽  
Myeloma Protein ◽  
Protein Core ◽  
Liquid Suspension ◽  
Peptide Component ◽  
Immunodominant Epitopes

An arabinogalactan-protein (AGP) purified from the filtrate of liquid-suspension-cultured Italian-ryegrass (Lolium multiflorum) endosperm cells by affinity chromatography on myeloma protein J539-Sepharose was deglycosylated with trifluoromethanesulphonic acid to remove polysaccharide chains that are covalently associated with hydroxyproline residues in the peptide component of the proteoglycan. The protein core, which accounts for less than 10% (w/w) of the intact proteoglycan, was purified by h.p.l.c. It has an apparent Mr of 35,000, but reacts very poorly with both Coomassie Brilliant Blue R and silver stains. Amino-acid-sequence analysis of the N-terminus of the h.p.l.c.-purified protein core and of tryptic peptides generated from the unpurified protein reveals a high content of hydroxyproline and alanine. These are sometimes arranged in short (Ala-Hyp) repeat sequences of up to six residues. Polyclonal antibodies raised against the protein core do not cross-react with native AGP, the synthetic peptide (Ala-Hyp)4, poly-L-hydroxyproline or poly-L-proline. The results suggest that the polysaccharide chains in the native AGP render the protein core of the proteoglycan inaccessible to the antibodies and that the immunodominant epitopes include domains of the protein other than those rich in Ala-Hyp repeating units.

Fine structure of the arabinogalactan-protein from Lolium multiflorum

1987 ◽  
Vol 162 (1) ◽  
pp. 85-93 ◽  
Author(s):  
Antony Bacic ◽  
Shirley C. Churms ◽  
Alistair M. Stephen ◽  
Peter B. Cohen ◽  
Geoffrey B. Fincher
Keyword(s):  
Fine Structure ◽  
Lolium Multiflorum ◽  
Arabinogalactan Protein

Biosynthesis of Arabinogalactan-Protein in Lolium multiflorum Ryegrass Endosperm Cells. I. Hydroxylation of Peptidyl Proline

1981 ◽  
Vol 8 (2) ◽  
pp. 121
Author(s):  
PC Pollard ◽  
GB Fincher
Keyword(s):  
Lolium Multiflorum ◽  
Total Radioactivity ◽  
Ferrous Ion ◽  
Arabinogalactan Protein ◽  
Trichloracetic Acid ◽  
Radioactive Label ◽  
Insoluble Material ◽  
Imino Acid ◽  
Proline Hydroxylation ◽  
Protein Moiety

Suspension-cultured endosperm cells from L. multiflorum secrete into the medium an arabinogalactan-protein in which the protein moiety is rich in hydroxyproline. When cells are grown in the presence of proline labelled with 14C or 3H, the imino acid is rapidly removed from the medium and radio- activity can subsequently be detected in extracellular trichloracetic acid-soluble, ethanol-insoluble material. In this fraction, which contains the arabinogalactan-protein and other polysaccharides, radioactive label is distributed between proline and hydroxyproline. α,α'-Dipyridyl, a chelator of ferrous ion, has no effect on the total radioactivity secreted but markedly alters the distribution of radioactivity in favour of peptidyl proline. Although this inhibition of peptidyl proline hydroxylation can be reversed by ferrous or zinc ions, it is not possible to conclude that ferrous ion, which is required for hydroxylation in other systems, participates specifically in the reaction in ryegrass endosperm cells. Concomitant with the inhibition of proline hydroxylation, α,α'-dipyridyl suppresses the biosynthesis or secretion of extracellular arabinogalactan-protein and arabinoxylan.

Biosynthesis of Arabinogalactan-Protein in Lolium multiflorum (Ryegrass) Endosperm Cells. II. In vitro Incorporation of Galactosyl Residues From UDPgalactose Into Polymeric Products

1982 ◽  
Vol 9 (1) ◽  
pp. 31 ◽  
Author(s):  
T Mascara ◽  
GB Fincher
Keyword(s):  
Cell Walls ◽  
Membrane Fraction ◽  
Lolium Multiflorum ◽  
Apparent Molecular Weight ◽  
Arabinogalactan Protein ◽  
Methylation Data ◽  
Myeloma Protein ◽  
Mouse Myeloma ◽  
Galactosyl Residues

When mixed-membrane fractions from suspension-cultured Lolium multiflorum endosperm cells are incubated in vitro with UDP-[14C]galactose, 66% ethanol-insoluble products of apparent molecular weight greater than 60 000 are labelled in both galactosyl and glucosyl residues, suggesting that an active UDPgalactose 4-epimerase is present on the membrane fraction. The epimerase can be inhibited with ADPribose, to produce polymeric material in which [14C]galactosyl residues pre-dominate. While some of these residues appear to be associated with glycoproteins, affinity chromatography of the products on mouse myeloma protein J539-Sepharose provides evidence that β-galactans containing 1,6-linkages are amongst the products. Monosaccharide analyses and methylation data indicate that the mixed-membrane preparations contain associated polysaccharide of structure analogous to the 1,3;1,4-β-glucans, arabinoxylans and arabino-3,6-galactans normally found in cell walls or secreted into the medium.

Uptake and Metabolism of Hydroxyproline in Endosperm Cells of Lolium multiflorum (Ryegrass)

1981 ◽  
Vol 8 (6) ◽  
pp. 535 ◽  
Author(s):  
PC Pollard ◽  
PW Way ◽  
GB Fincher
Keyword(s):  
Lolium Multiflorum ◽  
Metabolic Energy ◽  
Arabinogalactan Protein ◽  
Intracellular Protein ◽  
Pyrrolidine Ring ◽  
Peptide Linkage ◽  
Imino Acids ◽  
Hydroxyproline Metabolism ◽  
Uptake And Metabolism ◽  
Extracellular Fraction

Hydroxyproline is rapidly removed from the medium by suspension-cultured endosperm cells of ryegrass (Lolium multiflorum) in a process which exhibits Michaelis-Menten kinetics and is dependent on temperature and metabolic energy. Following uptake by the cells, hydroxyproline is rapidly converted to proline by a route which appears to be more direct than the pathways of hydroxyproline metabolism in mammalian and bacterial systems and which results in substantial conservation of the pyrrolidine ring. Four hours after providing the cells with 5.5 nM [3H]hydroxyproline, approximately 50% of the radioactivity is recovered as intracellular imino acids, intracellular protein and extracellular peptide material. The radioactivity is associated predominantly with proline and hydroxyproline residues. In common with other plant and animal systems, hydroxyproline is not incorporated directly into protein. However, radioactivity originating in extracellular hydroxyproline is detected eventually in peptide linkage, where it appears first as peptidyl proline. In the extracellular fraction which contains arabinogalactan-protein, peptidyl proline is hydroxylated to form peptidyl hydroxyproline and, after 4 h, approximately 18% of the original 3H label is found in this fraction.

scholarly journals Reaction of Some Invertebrate and Plant Agglutinins and a Mouse Myeloma Anti-Galactan Protein With an Arabinogalactan From Wheat

1978 ◽  
Vol 31 (2) ◽  
pp. 149 ◽  
Author(s):  
BA Baldo ◽  
H Neukom ◽  
BA Stone ◽  
G Uhlenbruck
Keyword(s):  
Ricinus Communis ◽  
Lolium Multiflorum ◽  
Arabinogalactan Protein ◽  
Myeloma Protein ◽  
Tridacna Maxima ◽  
The Difference ◽  
Inhibition Studies ◽  
Mild Acid ◽  
Mouse Myeloma ◽  
Galactosyl Residues

Plant, invertebrate and vertebrate proteins which show anti-galactan combining specificities were used in precipitation and inhibition studies with arabinogalactan preparations from wheat and ryegrass (Lolium multiflorum). Of the agglutinins studied, only mouse anti-galactan myeloma protein J539 showed strong reactivity with wheat arabinoglactan-peptide. Weak reactions were observed with the agglutinins from the clam Tridacna maxima, the sponge Axinella polypoides and the anemone Cerianthus membranaceus. No reactions were detected with lectins from the plants Abrus precatorius and Ricinus communis. Reactions readily occurred between Lolium arabinogalactan-protein and the invertebrate and vertebrate agglutinins. Removal of terminal arabinosyl residues from the wheat and Lotium arabinogalactans either by mild acid hydrolysis or by treatment with an arabinofuranosidase increased the reactivity of both peptidoglycans with all of the agglutinins examined except the Ricinus RCAl lectin. Results obtained with wheat arabinogalactan indicate that few D-galactose units are terminal and available for reaction. The difference in reactivities between the wheat and Lotium arabinogalactans may be due to the differences in the galactose:arabinose ratios or to differences in linkage of the galactosyl residues on the two peptidoglycans, or both. Results indicate that the mouse anti-galactan could be a useful reagent for the subcellular localization of wheat arabinogalactan and that tridacnin and Axinella agglutinins could be used to localize the arabinogalactan in L. multiflorum cells.

A Carbohydrate-Binding Arabinogalactan-Protein From Liquid Suspension Cultures of Endosperm From Lolium multiflorum

1977 ◽  
Vol 4 (1) ◽  
pp. 143 ◽  
Author(s):  
RL Anderson ◽  
AE Clarke ◽  
MA Jermyn ◽  
RB Knox ◽  
BA Stone
Keyword(s):  
Lolium Multiflorum ◽  
Molecular Size ◽  
Water Soluble ◽  
Arabinogalactan Protein ◽  
Carbohydrate Binding ◽  
Rye Grass ◽  
Liquid Suspension ◽  
Artificial Antigen ◽  
Lima Beans ◽  
Protein Portion

Water-soluble arabinogalactan-proteins have been isolated from tissue-cultured rye grass endosperm cells and their culture medium by precipitation with the β-glucosyl Yariv artificial antigen. The intracellular and extracellular polymers are similar in composition and molecular size (apparent mol. wt 2.2 — 2.8 × 105). The protein portion represents up to 7% of the molecule and is rich in hydroxyproline, alanine and serine. The carbohydrate portion (84%) consists solely of arabinose (36%) and galactose (64%) and methylation analysis shows it to be a branched 1,3 : 1,6-galactan substituted by arabinofuranosyl residues. The carbohydrate compositions and methylation analyses for polymers precipitated by the β-glucosyl Yariv antigen from lima beans, cashew, tomato, silver beet and asparagus and an arabinogalactan-peptide from wheat endosperm are compared. As a group, they show homologies both in their peptide and polysaccharide portions. A histochemical method, based on precipitation with the β-glucosyl Yariv antigen, showed the binding polymers to be localized in discrete irregular vesicles in the tissue-cultured rye grass endosperm cells. Native rye grass endosperm cells show staining between starch granules, and staining is also seen in the aleurone cells of barley, wheat and rye grass.

scholarly journals Biosynthesis of arabinogalactan-protein in Lolium multiflorum (Italian ryegrass) endosperm cells. Subcellular distribution of galactosyltransferases

1984 ◽  
Vol 218 (2) ◽  
pp. 633-636 ◽  
Author(s):  
A Schibeci ◽  
A Pnjak ◽  
G B Fincher
Keyword(s):  
Golgi Apparatus ◽  
Subcellular Distribution ◽  
Lolium Multiflorum ◽  
Italian Ryegrass ◽  
Arabinogalactan Protein ◽  
Enzyme Assays ◽  
Marker Enzyme ◽  
Carbohydrate Component ◽  
Myeloma Protein ◽  
Putative Marker

Intracellular membranes from protoplasts of Italian-ryegrass (Lolium multiflorum) endosperm cells have been fractionated on sucrose density gradients and identified on the basis of putative-marker-enzyme assays. Galactosyltransferases capable of incorporating galactose from UDP galactose into 66% ethanol-soluble products are associated with all membrane fractions. Affinity chromatography of the ethanol-insoluble products on (murine myeloma protein J539)-Sepharose reveals that the enzymes responsible for the synthesis of polymers containing (1→6)-beta-D-galactose residues are associated exclusively with subcellular fractions enriched in Golgi-derived membranes. This suggests that the Golgi apparatus plays an important part in the synthesis of the carbohydrate component of the ryegrass arabinogalactan-protein.

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