scholarly journals Characterization of xyloglucan-specific fucosyltransferase activity in Golgi-enriched microsomal preparations from wheat seedlings

2019 ◽  
Author(s):  
Richard E. Wiemels ◽  
Wei Zeng ◽  
Nan Jiang ◽  
Ahmed Faik

AbstractXyloglucan (XyG) is a major hemicellulosic polymer in primary cell walls of dicotyledonous plants but represents only a minor constituent of cell walls from graminaceous monocotyledons (Poaceae). Our current information on XyG biosynthesis in vitro comes exclusively from studies on dicotyledonous plants. While XyG has been reported in grass cell walls, there are no studies of XyG biosynthesis in vitro in grasses. In this report, we investigated XyG structure and biosynthesis in etiolated wheat seedlings and showed that their walls contain small amounts (4-14%) of XyG. Furthermore, structural analysis using electrospray ionization mass spectrometry (ESI-MS) and high pH anion exchange chromatography (HPAEC) revealed that wheat XyG may be of XXGGG-type. Interestingly, detergent extracts from root microsomes were able to fucosylate tamarind XyG in vitro in a similar way as fucosyltransferase activity from Arabidopsis thaliana (AtFUT1) and pea (PsFUT1). Endoglucanase digestion of the [14C]fucosylated-tamarind XyG formed by the wheat fucosyltransferase activity released radiolabeled oligosaccharides that co-eluted with authentic fucoslyated XyG oligosaccharides (XXFG and XLFG). Although wheat fucosyltransferase activity was low, it appeared to be specific to XyG and required divalent ions (Mg2+ or Mn2+) for full activity. Together, these results suggest that the XyG fucosylation mechanism is conserved between monocots and dicots.

1988 ◽  
Vol 89 (3) ◽  
pp. 387-395
Author(s):  
F. P. GIBSON ◽  
B. DAVID HAMES

Spore coat protein synthesis during development by submerged pseudoplasmodia of Dictyostelium discoideum requires a low molecular weight factor secreted by cells incubated at high density inbuffer. The further characterization of this sporeprotein inducing factor (SPIF) is reported. Its behaviour during anion-exchange chromatography and the loss of activity upon esterification suggests the presence of a carboxylic acid group essential for biological activity. Gel permeation chromatography resolves a major SPEF activity with Mr ∼ 160–200 and a minor activity with Mr ∼ 340–420. Anion-exchange HPLC further resolves the major SPIF activity into four components, one major and three minor. Methionine, analogues of methionine, and precursors of methioninebio synthesis are all effective in maintainingspore coat protein synthesis. Condition edmedium contains methionine at a concentration sufficient to account for its SPIF activity and this activity is abolished by cyanogen bromide treatment. These results indicate that SPIF is eithermethionine or a close analogue of methionine.


2021 ◽  
Vol 11 (7) ◽  
pp. 3212
Author(s):  
Noa Miguez ◽  
Peter Kidibule ◽  
Paloma Santos-Moriano ◽  
Antonio O. Ballesteros ◽  
Maria Fernandez-Lobato ◽  
...  

Chitooligosaccharides (COS) are homo- or hetero-oligomers of D-glucosamine (GlcN) and N-acetyl-D-glucosamine (GlcNAc) that can be obtained by chitosan or chitin hydrolysis. Their enzymatic production is preferred over other methodologies (physical, chemical, etc.) due to the mild conditions required, the fewer amounts of waste and its efficiency to control product composition. By properly selecting the enzyme (chitinase, chitosanase or nonspecific enzymes) and the substrate properties (degree of deacetylation, molecular weight, etc.), it is possible to direct the synthesis towards any of the three COS types: fully acetylated (faCOS), partially acetylated (paCOS) and fully deacetylated (fdCOS). In this article, we review the main strategies to steer the COS production towards a specific group. The chemical characterization of COS by advanced techniques, e.g., high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and MALDI-TOF mass spectrometry, is critical for structure–function studies. The scaling of processes to synthesize specific COS mixtures is difficult due to the low solubility of chitin/chitosan, the heterogeneity of the reaction mixtures, and high amounts of salts. Enzyme immobilization can help to minimize such hurdles. The main bioactive properties of COS are herein reviewed. Finally, the anti-inflammatory activity of three COS mixtures was assayed in murine macrophages after stimulation with lipopolysaccharides.


2021 ◽  
Author(s):  
Amrutha Bindu ◽  
Lakshmi Devi

Abstract The focus of present study was to characterize antimicrobial peptide produced by probiotic cultures, Enterococcus durans DB-1aa (MCC4243), Lactobacillus plantarum Cu2-PM7 (MCC4246) and Lactobacillus fermentum Cu3-PM8 (MCC4233) against Staphylococus aureus and E. coli. The growth kinetic assay revealed 24 h of incubation to be optimum for bacteriocin production. The partially purified compound after ion-exchange chromatography was found to be thermoresistant and stable under wide range of pH. The compound was sensitive to proteinase-K, but resistant to trypsin, a-amylase and lipase. The apparent molecular weight of bacteriocin from MCC4243 and MCC4246 was found to be 3.5 KDa. Translated partial amino acid sequence of plnA gene in MCC4246 displayed 48 amino acid sequences showing 100% similarity with plantaricin A of Lactobacillus plantarum (WP_0036419). The sequence revealed 7 β sheets, 6 α sheets, 6 predicted coils and 9 predicted turns. The functions on cytoplasm show 10.82 isoelectric point and 48.6% hydrophobicity. The molecular approach of using Geneious Prime software and protein prediction data base for characterization of bacteriocin is novel and predicts “KSSAYSLQMGATAIKQVKKLFKKWGW” as peptide responsible for antimicrobial activity. The study provides information about broad spectrum bacteriocin in native probiotic culture and paves a way towards its application in functional foods as biopreservative agents.


2002 ◽  
Vol 115 (9) ◽  
pp. 1973-1984
Author(s):  
Kwanghee Kim ◽  
Min Son ◽  
Joan B. Peterson ◽  
David L. Nelson

We purified two small, acidic calcium-binding proteins(ParameciumCa2+-binding proteins, PCBP-25α and PCBP-25β) from Paramecium tetraurelia by Ca2+-dependent chromatography on phenyl-Sepharose and by anion-exchange chromatography. The proteins were immunologically distinct. Monoclonal antibodies against PCBP-25β did not react with PCBP-25α, and antibodies against centrin from Chlamydomonas reacted with PCBP-25α but not with PCBP-25β. Like the centrins described previously, both PCBPs were associated with the infraciliary lattice (ICL), a fibrillar cytoskeletal element in Paramecium. Both were also present in isolated cilia, from which they could be released (with dynein) by a high-salt wash, and both PCBPs cosedimented with dynein in a sucrose gradient. PCBP-25β was especially prominent in cilia and in the deciliation supernatant, a soluble fraction released during the process of deciliation. The results of immunoreactivity and localization experiments suggest that PCBP-25α is a Paramecium centrin and that PCBP-25β is a distinct Ca2+-binding protein that confers Ca2+ sensitivity on some component of the cilium, ciliary basal body or ICL.We characterized these proteins and Paramecium calmodulin as substrates for two Ca2+-dependent protein kinases purified from Paramecium. PCBP-25α and calmodulin were in vitro substrates for one of the two Ca2+-dependent protein kinases (CaPK-2), but only PCBP-25α was phosphorylated by CaPK-1. These results raise the possibility that the biological activities of PCBP-25α and calmodulin are regulated by phosphorylation.


Blood ◽  
1992 ◽  
Vol 80 (4) ◽  
pp. 942-952 ◽  
Author(s):  
L Zhang ◽  
A Jhingan ◽  
FJ Castellino

Abstract To evaluate the contributions of individual gamma-carboxyglutamic acid (gla) residues to the overall Ca(2+)-dependent anticoagulant activity of activated human protein C (APC), we used recombinant (r) DNA technology to generate protein C (PC) variants in which each of the gla precursor glutamic acid (E) residues (positions 6, 7, 14, 16, 19, 20, 25, 26, and 29) was separately altered to aspartic acid (D). In one case, a gla26V mutation ([gla26V]r-PC) was constructed because a patient with this particular substitution in coagulation factor IX had been previously identified. Two additional r-PC mutants were generated, viz, an r-PC variant containing a substitution at arginine (R) 15 ([R15]r-PC), because this particular R residue is conserved in all gla- containing blood coagulation proteins, as well as a variant r-PC with substitution of an E at position 32 ([F31L, Q32E]r-PC), because gla residues are found in other proteins at this sequence location. This latter protein did undergo gamma-carboxylation at the newly inserted E32 position. For each of the 11 recombinant variants, a subpopulation of PC molecules that were gamma-carboxylated at all nonmutated gla- precursor E residues has been purified by anion exchange chromatography and, where necessary, affinity chromatography on an antihuman PC column. The r-PC muteins were converted to their respective r-APC forms and assayed for their amidolytic activities and Ca(2+)-dependent anticoagulant properties. While no significant differences were found between wild-type (wt) r-APC and r-APC mutants in the amidolytic assays, lack of a single gla residue at any of the following locations, viz, 7, 16, 20, or 26, led to virtual complete disappearance of the Ca(2+)-dependent anticoagulant activity of the relevant r-APC mutant, as compared with its wt counterpart. On the other hand, single eliminations of any of the gla residues located at positions 6, 14, or 19 of r-APC resulted in variant recombinant molecules with substantial anticoagulant activity (80% to 92%), relative to wtr-APC. Mutation of gla residues at positions 25 and 29 resulted in r-APC variants with significant but low (24% and 9% of wtr-APC, respectively) levels of anticoagulant activity. The variant, [R15L]r-APC, possessed only 19% of the anticoagulant activity of wrt-APC, while inclusion of gla at position 32 in the variant, [F31L, Q32gla]r-APC, resulted in a recombinant enzyme with an anticoagulant activity equivalent to that of wtr-APC.


1990 ◽  
Vol 269 (2) ◽  
pp. 393-402 ◽  
Author(s):  
P Ryden ◽  
R R Selvendran

1. Polymers were solubilized from the cell walls of parenchyma from mature runner-bean pods with minimum degradation by successive extractions with cyclohexane-trans-1,2-diamine-NNN′N′-tetra-acetate (CDTA), Na2CO3 and KOH to leave the alpha-cellulose residue, which contained cross-linked pectic polysaccharides and Hyp-rich glycoproteins. These were solubilized with chlorite/acetic acid and cellulase. The polymers were fractionated by anion-exchange chromatography, and fractions were subjected to methylation analysis. 2. The pectic polysaccharides differed in their ease of extraction, and a small proportion were highly cross-linked. The bulk of the pectic polysaccharides solubilized by CDTA and Na2CO3 were less branched than those solubilized by KOH. There was good evidence that most of the pectic polysaccharides were not degraded during extraction. 3. The protein-containing fractions included Hyp-rich and Hyp-poor glycoproteins associated with easily extractable pectic polysaccharides, Hyp-rich glycoproteins solubilized with 4M-KOH+borate, the bulk of which were not associated with pectic polysaccharides, and highly cross-linked Hyp-rich glycoproteins. 4. Isodityrosine was not detected, suggesting that it does not have a (major) cross-linking role in these walls. Instead, it is suggested that phenolics, presumably linked to C-5 of 3,5-linked Araf residues of Hyp-rich glycoproteins, serve to cross-link some of the polymers. 5. There were two main types of xyloglucan, with different degrees of branching. The bulk of the less branched xyloglucans were solubilized by more-concentrated alkali. The anomeric configurations of the sugars in one of the highly branched xyloglucans were determined by 13C-n.m.r. spectroscopy. 6. The structural features of the cell-wall polymers and complexes are discussed in relation to the structure of the cell walls of parenchyma tissues.


2010 ◽  
Vol 22 (1) ◽  
pp. 289
Author(s):  
C. R Ferreira ◽  
J. C. Borges ◽  
L. F. A. Santos ◽  
F. C. Gozzo ◽  
P. H. Franscechini ◽  
...  

Matrix-assisted laser desorption-ionization mass spectrometry (MALDI-MS) has been applied to study sperm lipid profiles. Lipids are known to play a crucial role in sperm membrane physico-chemical behavior during cryopreservation. In this work, we show the results of characterization of sperm lipid profiles from 2 bulls with different capacities of in vitro embryo production by MALDI-MS direct analysis. The bull capacities judged by the rate of blastocyst formation after IVP with semen from seven different ejaculates per each animal were 19.1 and 35.3% for bulls 1 and 2, respectively (P < 0.05). For MALDI-MS analysis, frozen semen from each ejaculate was thawed in water at 25°C for 40 s. Sperm was washed 3 times by centrifugatin in 1 mL of PBS at 3000 × g for 10 min. Samples were stored at -20°C in 200 μL of methanol:PBS (vol/vol) solution until analysis. A Synapt HDMS mass spectrometer (Waters Corp., Milford, MA, USA) equipped with a MALDI was used. All spectra were collected for 45 s in the positive ion mode at the mass range of m/z 450 to 1200. The volume of 1 μL of the semen pellet was spotted in the target plate and allowed to dry. Afterward, 1 μL of 2,5-dihydroxybenzoic acid (DHB) was added as matrix. The 50 most intense monoisotopic ions were considered for principal component analysis (PCA). Values of m/z and relative ion intensities were processed using the software Pirouette v.3.11 (Infometrix, Woodinville, WA, USA). Direct MALDI-MS analysis of bulls 1 and 2 spermatozoa with no extraction provided informative spectra containing either [M + Na]+ or [M + H]+ ions characteristic of sphingomyelins, such as m/z 753.6 for SM 18:0, phosphocholines (m/z 780.6 for PC 34 : 2; 782.6 for PC 34 : 1; 806.6 for PC 36 : 6; 808.6 for 36 :2; 828.6 for PC38 : 6; and 830.6 for PC38 : 5), plasmalogens (m/z 790.6 for 1-palmitenyl-2-docosahexanoyl-GPC and 814.6 for 1-palmityl-2-docosaheaenoyl-GPC); and triacylglycerols (m/z 881.7 for sn-glycerol-palmitoleate-oleate-oleate). PCA showed clear separation between bulls 1 and 2 ejaculates, indicating that each bull presented a characteristic and reproducible (from different ejaculates) profiles. Differences in the relative intensities of the ions mentioned above contributed for bulls 1 and 2 differentiation by PCA. PC1 and PC2 explained 86.5% of the data variance. In conclusion, a fast sample preparation protocol followed by MALDI-MS appears to provide characteristic lipid fingerprints for crude spermatozoa (ejaculates) of bulls with different capacities of embryo in vitro production. Experiments involving a larger and more statically relevant set of samples are underway. We thank the Brazilian research foundations FAPESP (2008/10756-7) and CNPq.


2018 ◽  
Vol 13 (12) ◽  
pp. 1934578X1801301
Author(s):  
Huiqin Wang ◽  
Guanzhen Gao ◽  
Lijing Ke ◽  
Jianwu Zhou ◽  
Pingfan Rao

A novel lectin-like protein with MW 63.2 kDa, designated as SBLP, has been isolated and characterized from the dried roots of Scutellaria baicalensis Georgi (Lamiaceae). SBLP was purified by ammonium sulfate precipitation and anion exchange chromatography. It is a glycoprotein according to a PAS staining assay and consisting of protein (86.0%) and sugar (14.0%). Its N-terminal amino acid sequence was determined as GSAVGFLY by Edman degradation. SBLP showed hemagglutinating activity against human and rooster erythrocytes, which were stable below 60°C and in the pH range of 4 −10. Furthermore, SBLP was found to be stimulated by Ca2+, Na+, Ba2+, Zn2+ ions, which suggested it was a metal-dependent lectin. SBLP inhibited the growth of Fusarium oxysporum f.sp. lycopersici and Alternaria eichhorniae in the a dose-dependent manner, and suppressed the proliferation of HepG2 tumor cells with an IC50 of 1.00 μM. This is the first report of a lectin from Radix Scutellariae.


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