scholarly journals Purification and characterization of a sialic acid-specific lectin from Tritrichomonas mobilensis

1994 ◽  
Vol 299 (2) ◽  
pp. 341-346 ◽  
Author(s):  
P Babál ◽  
F F Pindak ◽  
D J Wells ◽  
W A Gardner
Keyword(s):  
Monoclonal Antibodies ◽  
Sialic Acid ◽  
Haemagglutination Inhibition ◽  
Submaxillary Gland ◽  
Inhibitory Effect ◽  
Size Exclusion ◽  
Western Blots ◽  
Reducing Conditions ◽  
Sds Page ◽  
Exclusion Chromatography

New sialic acid-specific lectin has been isolated from culture supernatant of the protozoan Tritrichomonas mobilensis. It was purified by adsorption by erythrocytes or bovine submaxillary gland mucin (BSM)-Sepharose affinity chromatography. The T. mobilensis lectin (TML) does not require bivalent cations for activity and agglutinates all human erythrocytes. The lectin forms multimeric complexes with molecular mass 556 and 491 kDa as determined by size-exclusion chromatography. SDS/PAGE under reducing conditions disclosed a large band of 343 kDa and three bands of 246, 265 and 286 kDa which, after denaturation with urea, were split into three subunits of 56, 61 and 66 kDa; under non-reducing conditions there were two bands, of 360 and 260 kDa. Western blots performed with anti-TML monoclonal antibodies revealed bands identical with those in the silver-stained gels, suggesting homogeneity of the BSM -Sepharose-purified lectin. TML is a highly glycosylated protein with approx. 8% of N-linked glycosides found by protein-N-glycanase F treatment; the total amount of saccharides revealed by chemical deglycosylation was 20%. Haemagglutination-inhibition studies documented exclusive specificity for sialic acid (NeuAc). Both (alpha 2->6)- and (alpha 2->3)-linked and free NeuAc were eight times more potent inhibitors than N-glycolylneuraminic acid. The lectin does not require O-acetyl groups on NeuAc for recognition. A spectrum of mono- and oligo-saccharides other than sialic acid had no inhibitory effect at 200 mM. Anti-TML monoclonal antibodies strongly inhibited the lectin activity. TML was stable at temperatures below 4 degrees C and lyophilized with 3% (w/w) glycerol.

PLATELETS OF A PATIENT LACKING GLYCOPROTEINS lib AND Ilia AGGREGATE TO HIGH CONCENTRATIONS OF THROMBIN OR COLLAGEN

1987 ◽  
Author(s):  
J L McGregor ◽  
L McGregor ◽  
M Hans ◽  
A Sayegh ◽  
M C Trzeeiak ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Polyclonal Antibodies ◽  
Two Dimensional ◽  
Binding Studies ◽  
Western Blots ◽  
Glycoprotein Complex ◽  
Sds Page ◽  
Bleeding Episodes ◽  
High Concentrations ◽  
Induced Aggregation

The aim of this study was to investigate the platelets of a patient having bleeding episodes that began in infancy. The patient’s platelets in citrated-PRP did not aggregate when stimulated with ADP (5 and 10 uM), collagen (2.5 ug/ml), or sodium arachidonate (1 uM). However, washed patient platelets, in the presence of 2mM calcium, aggregated and secreted when stimulated with high concentrations of thrombin (0.36, 0.72 and lU/ml) or collagen (2, 4, 10 ug/ml). Monoclonal antibodies (Mab) LYP18 (directed against the IIb-IIIa glycoprotein complex) and LYP8 (anti-thrombospondin) inhibited thrombin and collagen induced aggregation of control but not the patient platelets. Patient thrombin -stimulated platelets did not bind 125I-labelled fibrinogen (40 to 320 ug/ml). Moreover, stimulating the washed patient's platelets with ADP (10-100 uM), in the presence of fibrinogen (2mg/ml), did not result in aggregation. Binding studies using Mab 125I-LYP2 (directed against the IIb-IIIa glycoprotein complex) showed the absence of the complex on the patient's platelets. The absence of the IIb-IIIa complex on the patient's platelets was also observed using crossed immunoelectro -phoresis and Mab 125I-LYP2 or 125I-LYP18. Individual glycoproteins (lib or Ilia) were not detected on silver stained two-dimensional (non-reduced/reduced) SDS-PAGE. Moreover, Western blots of |he patients platelets used in combination with anti-PLA or anti-LEK polyclonal antibodies failed to detect the presence of these two glycoproteins. These results indicate that this patient has Glanzmann's thrombasthenia or a variant of this disease. Moreover, this study shows that platelets lacking the IIb-IIIa glycoprotein complex can aggregate in responseto collagen or thrombin in the presence of physiological concentrations of calcium.

scholarly journals Molecular cloning and biochemical characterization of rabbit factor XI

2002 ◽  
Vol 367 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Dipali SINHA ◽  
Mariola MARCINKIEWICZ ◽  
David GAILANI ◽  
Peter N. WALSH
Keyword(s):  
Human Factor ◽  
Biochemical Characterization ◽  
Protein A ◽  
Size Exclusion ◽  
Factor Xi ◽  
Sds Page ◽  
Exclusion Chromatography ◽  
Intracellular Process ◽  
And Function

Human factor XI, a plasma glycoprotein required for normal haemostasis, is a homodimer (160kDa) formed by a single interchain disulphide bond linking the Cys-321 of each Apple 4 domain. Bovine, porcine and murine factor XI are also disulphide-linked homodimers. Rabbit factor XI, however, is an 80kDa polypeptide on non-reducing SDS/PAGE, suggesting that rabbit factor XI exists and functions physiologically either as a monomer, as does prekallikrein, a structural homologue to factor XI, or as a non-covalent homodimer. We have investigated the structure and function of rabbit factor XI to gain insight into the relation between homodimeric structure and factor XI function. Characterization of the cDNA sequence of rabbit factor XI and its amino acid translation revealed that in the rabbit protein a His residue replaces the Cys-321 that forms the interchain disulphide linkage in human factor XI, explaining why rabbit factor XI is a monomer in non-reducing SDS/PAGE. On size-exclusion chromatography, however, purified plasma rabbit factor XI, like the human protein and unlike prekallikrein, eluted as a dimer, demonstrating that rabbit factor XI circulates as a non-covalent dimer. In functional assays rabbit factor XI and human factor XI behaved similarly. Both monomeric and dimeric factor XI were detected in extracts of cells expressing rabbit factor XI. We conclude that the failure of rabbit factor XI to form a covalent homodimer due to the replacement of Cys-321 with His does not impair its functional activity because it exists in plasma as a non-covalent homodimer and homodimerization is an intracellular process.

scholarly journals Human platelet glycoprotein IIIb binds to thrombospondin fragments bearing the C-terminal region, and/or the type I repeats (CSVTCG motif), but not to the N-terminal heparin-binding region

1992 ◽  
Vol 284 (1) ◽  
pp. 231-236 ◽  
Author(s):  
B Catimel ◽  
L Leung ◽  
H el Ghissasi ◽  
N Mercier ◽  
J McGregor
Keyword(s):  
Plasmodium Falciparum ◽  
Sequence Similarity ◽  
Terminal Region ◽  
Platelet Glycoprotein ◽  
Affinity Column ◽  
Type I ◽  
Heparin Binding ◽  
Western Blots ◽  
Reducing Conditions ◽  
Sds Page

Major blood membrane platelet glycoprotein IIIb (GPIIIb), also termed GPIV or CD365, has been identified as a receptor for thrombospondin (TSP), collagen and Plasmodium falciparum-infected erythrocytes. The aim of the present study was to identify region(s) of TSP involved in binding of GPIIIb. Proteolytic fragments of TSP (M(r) 140 kDa, 120-18 kDa and 27 kDa on SDS/PAGE under reducing conditions) were purified by f.p.l.c. and identified by N-terminal gas-phase sequencing, e.l.i.s.a. and Western blots using monoclonal antibodies directed against defined domains of TSP. The 140 kDa and 120-18 kDa fragments (C-terminal region), but not the 27 kDa fragment (N-terminal region), were shown to bind to GPIIIb by using e.l.i.s.a. and affinity-chromatography systems. TSP binding to a GPIIIb-affinity column was Ca(2+)-dependent and reduced by 45% in the presence of EDTA. Moreover, TSP was only partially eluted with EDTA from a Ca(2+)-equilibrated GPIIIb column. A fragment of 68 kDa, obtained by further digestion of the 140 kDa fragment, bound to the GPIIIb-Sepharose affinity column. This fragment, or stalk-like region, bears the TSP type I repeats that show sequence similarity to regions on properdin, Plasmodium falciparum proteins and antistasin. Peptides (CSVTCG or SVTCGGGV) representing these repeats bound isolated GPIIIb in a Ca(2+)-independent way, but did not completely inhibit the GPIIIb and TSP interaction. These studies indicate that GPIIIb binds to the TSP via the C-terminal region and/or the CSVTCG motif, but not to the N-terminal region. Interaction between GPIIIb and the TSP C-terminal region or the CSVTCG motif is respectively Ca(2+)-dependent and -independent.

Important role of fungal intracellular laccase for melanin synthesis: purification and characterization of an intracellular laccase from Lentinula edodes fruit bodies

Microbiology ◽  
2003 ◽  
Vol 149 (9) ◽  
pp. 2455-2462 ◽  
Author(s):  
Masaru Nagai ◽  
Maki Kawata ◽  
Hisayuki Watanabe ◽  
Machiko Ogawa ◽  
Kumiko Saito ◽  
...  
Keyword(s):  
Lentinula Edodes ◽  
Veratryl Alcohol ◽  
Size Exclusion ◽  
Melanin Synthesis ◽  
Sds Page ◽  
Diammonium Salt ◽  
Exclusion Chromatography ◽  
Homogeneous Preparation

A laccase (EC 1.10.3.2) was isolated from the fully browned gills of Lentinula edodes fruit bodies. The enzyme was purified to a homogeneous preparation using hydrophobic, cation-exchange and size-exclusion chromatography. SDS-PAGE analysis showed the purified laccase, Lcc 2, to be a monomeric protein of 58·0 kDa. The enzyme had an isoelectric point of around pH 6·9. The optimum pH for enzyme activity was around 3·0 against 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt (ABTS), and it was most active at 40 °C and stable up to 50 °C. The enzyme contained 8·6 % carbohydrate and some copper atoms. The enzyme oxidized ABTS, p-phenylenediamine, pyrogallol, guaiacol, 2,6-dimethoxyphenol, catechol and ferulic acid, but not veratryl alcohol and tyrosine. β-(3,4-Dihydroxyphenyl)alanine (l-DOPA), which was not oxidized by a laccase previously reported from the culture filtrate of L. edodes, was also oxidized by Lcc 2, and the oxidative product of l-dopa was identified as l-DOPA quinone by HPLC analysis. Lcc 2 was able to oxidize phenolic compounds extracted from fresh gills to brown-coloured products, suggesting a role for laccase in melanin synthesis in this strain.

scholarly journals Single extracellular vesicle analysis performed by imaging flow cytometry in contrast to NTA rigorously assesses the accuracy of urinary extracellular vesicle preparation techniques

2021 ◽  
Author(s):  
Marvin Droste ◽  
Tobias Tertel ◽  
Stefanie Jeruschke ◽  
Robin Dittrich ◽  
Evangelia Kontopoulou ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Method Comparison ◽  
Extracellular Vesicle ◽  
Size Exclusion ◽  
Western Blots ◽  
Preparation Methods ◽  
Imaging Flow Cytometry ◽  
Particle Yield ◽  
Exclusion Chromatography ◽  
Ultra Filtration

Extracellular vesicles (EVs) from several body fluids, including urine, appear as promising biomarkers. Within the last decade, numerous groups have compared the efficacy of EV preparation protocols. Frequently, the efficacy of EV preparation methods is judged by the recovery of particles as estimated by conventional nanoparticle tracking analysis (NTA) or other particle quantification devices. Here, at the example of different urinary EV (uEV) preparation methods, we determined the particle yield in obtained samples with conventional NTA, analyzed their EV content by imaging flow cytometry (IFCM) and quantified the intensity of TSG101 and the contaminant protein uromodulin (UMOD) in Western blots. Our results demonstrate a correlation among CD9-positive objects detected by IFCM and TSG101 Western blot intensities, while particle numbers as determined by NTA correlated with the amount of UMOD. Consequently, our results question the reliability of conventional NTA analyses for identifying the optimal EV preparation method. Here, in our method comparison, a combination of size exclusion chromatography followed by ultra-filtration showed the highest CD9-positive object and TSG101 protein recovery, and in relation to the number of CD9-positive objects, the lowest amount of UMOD contamination.

scholarly journals The interaction of the mitochondrial protein importer TOMM34 with HSP70 is regulated by TOMM34 phosphorylation and binding to 14-3-3 adaptors

2020 ◽  
Vol 295 (27) ◽  
pp. 8928-8944 ◽  
Author(s):  
Filip Trcka ◽  
Michal Durech ◽  
Pavla Vankova ◽  
Veronika Vandova ◽  
Oliver Simoncik ◽  
...  
Keyword(s):  
Structural Changes ◽  
Protein Transport ◽  
Mitochondrial Protein ◽  
Inhibitory Effect ◽  
Size Exclusion ◽  
Tetratricopeptide Repeat ◽  
Interaction Interface ◽  
Exclusion Chromatography ◽  
Hydrogen Deuterium

Translocase of outer mitochondrial membrane 34 (TOMM34) orchestrates heat shock protein 70 (HSP70)/HSP90–mediated transport of mitochondrial precursor proteins. Here, using in vitro phosphorylation and refolding assays, analytical size-exclusion chromatography, and hydrogen/deuterium exchange MS, we found that TOMM34 associates with 14-3-3 proteins after its phosphorylation by protein kinase A (PKA). PKA preferentially targeted two serine residues in TOMM34: Ser93 and Ser160, located in the tetratricopeptide repeat 1 (TPR1) domain and the interdomain linker, respectively. Both of these residues were necessary for efficient 14-3-3 protein binding. We determined that phosphorylation-induced structural changes in TOMM34 are further augmented by binding to 14-3-3, leading to destabilization of TOMM34's secondary structure. We also observed that this interaction with 14-3-3 occludes the TOMM34 interaction interface with ATP-bound HSP70 dimers, which leaves them intact and thereby eliminates an inhibitory effect of TOMM34 on HSP70-mediated refolding in vitro. In contrast, we noted that TOMM34 in complex with 14-3-3 could bind HSP90. Both TOMM34 and 14-3-3 participated in cytosolic precursor protein transport mediated by the coordinated activities of HSP70 and HSP90. Our results provide important insights into how PKA-mediated phosphorylation and 14-3-3 binding regulate the availability of TOMM34 for its interaction with HSP70.

scholarly journals The rapid “teabag” method for high-end purification of membrane proteins

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jenny Hering ◽  
Julie Winkel Missel ◽  
Liying Zhang ◽  
Anders Gunnarsson ◽  
Marie Castaldo ◽  
...  
Keyword(s):  
Applied Sciences ◽  
Membrane Proteins ◽  
Size Exclusion ◽  
Purification Method ◽  
New Approach ◽  
Purification Time ◽  
Sds Page ◽  
Exclusion Chromatography ◽  
Processing Steps

Abstract Overproduction and purification of membrane proteins are generally challenging and time-consuming procedures due to low expression levels, misfolding, and low stability once extracted from the membrane. Reducing processing steps and shortening the timespan for purification represent attractive approaches to overcome some of these challenges. We have therefore compared a fast “teabag” purification method with conventional purification for five different membrane proteins (MraY, AQP10, ClC-1, PAR2 and KCC2). Notably, this new approach reduces the purification time significantly, and the quality of the purified membrane proteins is equal to or exceeds conventional methods as assessed by size exclusion chromatography, SDS-PAGE and downstream applications such as ITC, crystallization and cryo-EM. Furthermore, the method is scalable, applicable to a range of affinity resins and allows for parallelization. Consequently, the technique has the potential to substantially simplify purification efforts of membrane proteins in basic and applied sciences.

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