scholarly journals Characterization and purification of a novel dATP-binding protein in eukaryotes

1992 ◽  
Vol 287 (3) ◽  
pp. 871-879 ◽  
Author(s):  
A Dalton ◽  
D P Hornby ◽  
S P Langston ◽  
G M Blackburn
Keyword(s):  
Binding Protein ◽  
Active Form ◽  
Direct Interaction ◽  
Nuclear Fraction ◽  
Yeast Saccharomyces Cerevisiae ◽  
Naturally Occurring ◽  
Sds Page ◽  
Marked Preference ◽  
High Degree ◽  
Page Electrophoresis

We characterized and purified an acidic dATP-binding protein, which, in its active form, resides in the nuclear fraction of a range of cells from mammals (including pig liver) and baker's yeast (Saccharomyces cerevisiae). This protein exhibits a high degree of specificity for the deoxy form of the naturally occurring nucleoside triphosphates and shows a marked preference for the purine deoxynucleoside triphosphates dATP and dGTP. The protein cleaves the terminal phosphate of dATP and appears to retain the dADP moiety of the nucleotide in a reaction that is resistant to both SDS and 8 M-urea. Fractionation of the nuclear preparation followed by non-denaturing PAGE and SDS/PAGE electrophoresis was sufficient to produce pure protein. The occurrence of this activity in all nuclei tested suggests that it plays an important role in nuclear metabolism. The specificity of the enzyme for deoxynucleoside triphosphates further suggests a role for this enzyme in DNA replication or repair, but the acidity of the protein argues against a direct interaction with DNA, and, indeed, the catalytic activity is not modulated by the inclusion of DNA in a variety of physical forms.

scholarly journals Solubilization and purification of a membrane-associated 3,3′,5-tri-iodo-l-thyronine-binding protein from rat erythrocytes

1990 ◽  
Vol 270 (3) ◽  
pp. 577-582 ◽  
Author(s):  
R C Angel ◽  
J A Botta ◽  
R D Morero ◽  
R N Farias
Keyword(s):  
Hormone Receptors ◽  
Specific Binding ◽  
Binding Protein ◽  
Active Form ◽  
Binding Activity ◽  
Erythrocyte Membranes ◽  
Major Protein ◽  
Sds Page ◽  
Affinity Labelling ◽  
Zwitterionic Detergent

3,3′,5-Tri-iodo-L-thyronine (L-T3) binding sites from rat erythrocyte membranes were solubilized in an active form by using the zwitterionic detergent CHAPS or the anionic detergent lauroylsarcosine. The binding protein was successively purified by Sephadex G-200 and affinity chromatography. The purified material retained its binding activity and exhibited high affinity and specificity compared with those displayed in the original membrane. Yield was about 10% of the starting activity. The specific binding activity was enriched by approx. 100-fold, which represents a purity of only 0.1%. Analysis of the purified preparation on SDS/PAGE showed two major protein bands (Mr 64,000 and Mr 50,000), but these could not represent the binding protein since the purity obtained was low. However, affinity-labelling experiments with N-bromoacetyl-L-[125I]T3 in intact membranes showed that two proteins (also with Mr values of 64,000 and 50,000) bound the hormone specifically, suggesting a co-migration of hormone receptors and contaminants on gel electrophoresis.

scholarly journals Purification and Characterization of Glutathione Binding Protein GsiB from Escherichia coli

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Zhongshan Wang ◽  
Xiaokun Xia ◽  
Meixian Zhang ◽  
Jiawei Fang ◽  
Yanqiang Li ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Knockout ◽  
Binding Protein ◽  
Gel Filtration ◽  
Direct Interaction ◽  
Protein Band ◽  
Sulfur Source ◽  
E Coli ◽  
Sds Page ◽  
Glutathione Binding

Objectives. To purify and characterize the glutathione binding protein GsiB of glutathione importer (GSI) in Escherichia coli (E. coli). Results. The coding sequence of GsiB was cloned from E. coli MG1655 and expressed in BL21(DE3). GsiB protein was expressed and purified to homogeneity using Ni-affinity and gel filtration chromatography. SDS-PAGE of purified GsiB showed a single protein band of molecular mass 56 kDa, while native gel showed two bands around 56 kDa and 110 kDa. Gene knockout showed that GsiB was essential for GSI mediated glutathione import. Interactions of GsiA, B, C, and D were determined using bacterial two-hybrid method. Without glutathione, GsiB showed no direct interaction with the other three proteins. However, GsiB could interact with GsiC and GsiD when using glutathione as sole sulfur source. Conclusions. GsiB functions in E. coli was characterized which could help elucidate the glutathione import mechanism in gram-negative bacteria.

Detection of both Type 1 and Type 2 Plasminogen Activator Inhibitors in Human Monocytes

1990 ◽  
Vol 63 (01) ◽  
pp. 067-071 ◽  
Author(s):  
Joan C Castellote ◽  
Enric Grau ◽  
Maria A Linde ◽  
Nuria Pujol-Moix ◽  
Miquel LI Rutllant
Keyword(s):  
Molecular Mass ◽  
Plasminogen Activator ◽  
Human Peripheral Blood ◽  
Direct Interaction ◽  
Apparent Molecular Weight ◽  
Fibrinolytic System ◽  
Human Monocytes ◽  
Blood Monocytes ◽  
Single Chain ◽  
Sds Page

SummaryIncreasing evidence suggests the involvement of leukocytes in the fibrinolytic system. Monocytes secrete pro-urokinase (Grau, Thromb Res 1989; 53: 145) and it has been shown that these cells have specific receptors for urokinase and plasminogen (Miles, Thromb Haemostas 1987; 58: 936). The aim of this study was to analyse the presence of plasminogen activator inhibitor(s) in platelet-free suspensions of human peripheral blood monocytes and polymorphonuclear leukocytes (PMN). SDS-PAGE and reverse fibrin autography showed an inhibitory band of 50 kDa in the monocyte extracts (Triton X-100) but not in the PMN extracts. Urokinase (u-PA) was mixed with increasing amounts of monocyte extract for 10 min and the mixtures were added to 125Ifibrin coated wells containing plasminogen. A dose-dependent decrease in the u-PA fibrinolytic activity was observed. The amount of inhibition increased when the monocyte releasates were preincubated with u-PA (40% inhibition after 5 min preincubation and 80% after 15 min), indicating a direct interaction between this activator and an inhibitor(s). After SDS-PAGE of monocyte extracts, immunoblotting and peroxidase staining identified both PAI1 and PAI2, with an apparent molecular weight of 47-50 kDa. Monocyte-associated PAI1 formed complexes with single chain t-PA with a molecular mass 50 kDa higher than the molecular mass of the free PAI1. However, a significant amount of PAI remained unbound to t-PA. This inactive PAI1 could have come from a rapid inactivation of the primary active PAI1. These PAI1 and PAI2 detected in human monocytes may be transcendent in the regulation of the fibrinolytic system.

ASSOCIATION BEHAVIOUR OF THE OESTRADIOL-BINDING PROTEIN COMPLEX WITH THE NUCLEAR FRACTION

1972 ◽  
Vol 71 (2_Suppla) ◽  
pp. S420-S438 ◽  
Author(s):  
David L. Williams ◽  
Jack Gorski
Keyword(s):  
Binding Site ◽  
Protein Complex ◽  
Binding Protein ◽  
Nuclear Fraction ◽  
Site Saturation ◽  
Total Binding

ABSTRACT A number of studies have been carried out to examine the distribution of the oestradiol-binding protein complex between cytosol and nuclear fractions as a function of total binding site saturation. The results of these studies suggest that each binding protein has one binding site for the hormone. In addition, these studies suggest that the interaction of the oestradiol-binding protein complex with the nucleus involves a large number of low affinity association sites.

scholarly journals Studies on regulation of IGF (insulin-like growth factor)-binding protein (IGFBP) 4 proteolysis by pregnancy-associated plasma protein-A (PAPP-A) in cells treated with phorbol ester

2004 ◽  
Vol 379 (1) ◽  
pp. 57-64 ◽  
Author(s):  
Arun S. SIVANANDAM ◽  
Subburaman MOHAN ◽  
Hirohito KITA ◽  
Sanjay KAPUR ◽  
Shin-Tai CHEN ◽  
...  
Keyword(s):  
Growth Factor ◽  
Proteolytic Activity ◽  
Plasma Protein ◽  
Binding Protein ◽  
Protein A ◽  
Insulin Like Growth Factor ◽  
Factor Binding ◽  
Fold Reduction ◽  
Sds Page ◽  
Eosinophil Major Basic Protein

PAPP-A (pregnancy-associated plasma protein-A) is produced by hSFs (human skin fibroblasts) and hOBs (human osteoblasts) and enhances the mitogenic activity of IGFs (insulin-like growth factors) by degradation of IGFBP-4 (insulin-like growth factor-binding protein 4). PKC (protein kinase C) activation in these cells led to reduction in IGFBP-4 proteolysis. This study was undertaken to determine the mechanism by which activation of PKC suppresses IGFBP-4 proteolysis. Treatment of hSFs/hOBs with TPA (PMA; 100 nM) reduced IGFBP-4 proteolysis without significantly decreasing the PAPP-A level in the CM (conditioned medium). Immunodepletion of the proform of eosinophil major basic protein (proMBP), a known PAPP-A inhibitor, from CM of TPA-treated cells (TPA CM) failed to increase IGFBP-4 proteolytic activity. Transduction of hSFs with proMBP retrovirus increased the concentration of proMBP up to 30 ng/ml and led to a moderate reduction in IGFBP-4 proteolysis. In contrast, TPA treatment blocked IGFBP-4 proteolysis but failed to induce a detectable amount of proMBP in the CM. While proMBP overexpression led to the formation of a covalent proMBP–PAPP-A complex and reduced the migration of PAPP-A on SDS/PAGE, TPA treatment dose- and time-dependently increased the conversion of a ≈470 kDa PAPP-A form (PAPP-A470) to a ≈400 kDa PAPP-A form (PAPP-A400). Since unreduced PAPP-A400 co-migrated with the 400 kDa recombinant PAPP-A homodimer and since PAPP-A monomers from reduced PAPP-A470 and PAPP-A400 co-migrated on SDS/PAGE, conversion of PAPP-A470 to PAPP-A400 is unlikely to be caused by proteolytic cleavage of PAPP-A. Consistent with the data showing that the increase in the ratio of PAPP-A400/PAPP-A470 is correlated with the extent of reduction in IGFBP-4 proteolysis, partially purified PAPP-A400 exhibited a 4-fold reduction in IGFBP-4 proteolytic activity compared with PAPP-A470. These data suggest that a novel mechanism, namely conversion of PAPP-A470 to the less-active PAPP-A400, could account for the TPA-induced suppression of PAPP-A activity.

Direct interaction of the tau 1 transactivation domain of the human glucocorticoid receptor with the basal transcriptional machinery

1993 ◽  
Vol 13 (1) ◽  
pp. 399-407
Author(s):  
I J McEwan ◽  
A P Wright ◽  
K Dahlman-Wright ◽  
J Carlstedt-Duke ◽  
J A Gustafsson
Keyword(s):  
Glucocorticoid Receptor ◽  
Protein Interactions ◽  
Core Promoter ◽  
Specific Interaction ◽  
Direct Interaction ◽  
Dependent Manner ◽  
Transactivation Domain ◽  
Yeast Saccharomyces Cerevisiae ◽  
Concentration Dependent Manner

We have used a yeast (Saccharomyces cerevisiae) cell free transcription system to study protein-protein interactions involving the tau 1 transactivation domain of the human glucocorticoid receptor that are important for transcriptional transactivation by the receptor. Purified tau 1 specifically inhibited transcription from a basal promoter derived from the CYC1 gene and from the adenovirus 2 major late core promoter in a concentration-dependent manner. This inhibition or squelching was correlated with the transactivation activity of tau 1. Recombinant yeast TATA-binding protein (yTFIID), although active in vitro, did not specifically reverse the inhibitory effect of tau 1. In addition, no specific interaction between tau 1 and yTFIID could be shown in vitro by affinity chromatography. Taken together, these results indicate that the tau 1 transactivation domain of the human glucocorticoid receptor interacts directly with the general transcriptional apparatus through some target protein(s) that is distinct from the TATA-binding factor. Furthermore, this assay can be used to identify interacting factors, since after phosphocellulose chromatography of a whole-cell yeast extract, a fraction that contained an activity which selectively counteracted the squelching effect of tau 1 was found.

Degradation of ornithine decarboxylase: exposure of the C-terminal target by a polyamine-inducible inhibitory protein

1993 ◽  
Vol 13 (4) ◽  
pp. 2377-2383
Author(s):  
X Li ◽  
P Coffino
Keyword(s):  
Conformational Change ◽  
Ornithine Decarboxylase ◽  
Binding Protein ◽  
Active Form ◽  
Feedback Regulation ◽  
Degradation Process ◽  
Protein Inhibitor ◽  
Inhibitory Protein ◽  
C Terminus ◽  
N Terminus

Polyamine-mediated degradation of vertebrate ornithine decarboxylase (ODC) is associated with the production of antizyme, a reversible tightly binding protein inhibitor of ODC activity. The interaction of antizyme with a binding element near the N terminus of ODC is essential but not sufficient for regulation of the enzyme by polyamines (X. Li and P. Coffino, Mol. Cell. Biol. 12:3556-2562, 1992). We now show that a second element present at the C terminus is required for the degradation process. Antizyme caused a conformational change in ODC, which made the C terminus of ODC more accessible. Blocking the C terminus with antibody prevented degradation. Tethering the C terminus by creating a circularly permuted, enzymatically active form of ODC prevented antizyme-mediated degradation. These data elucidate a form of feedback regulation whereby excess polyamines induce destruction of ODC, the enzyme that initiates their biosynthesis.

scholarly journals Establishment of peritoneal liquid electrophoretogram from healthy horses and horses submitted to experimentally induced intestinal obstruction

2014 ◽  
Vol 66 (3) ◽  
pp. 665-671 ◽  
Author(s):  
A.F.S. Nogueira ◽  
P.A. Di Filippo ◽  
L.A. Anai ◽  
M.C. Vieira ◽  
K.M.M.G. Simplício ◽  
...  
Keyword(s):  
Intestinal Obstruction ◽  
Acute Phase ◽  
Acute Phase Proteins ◽  
Immunoglobulin A ◽  
Control Group ◽  
Protein Levels ◽  
Sds Page ◽  
Significant Difference ◽  
Page Electrophoresis ◽  
Experimentally Induced

The initial inflammatory stages of the colic syndrome include changes known as acute phase response. The aim of this study was to contribute with the establishment of reference values concerning the electrophoretogram of peritoneal liquid from healthy horses and horses submitted to experimentally induced intestinal obstruction. Twenty-one horses were allotted in four groups: duodenal obstruction (DG), ileum obstruction (IG), left-dorsal colon obstruction (MG), and control group (CG). Peritoneal liquid was sampled before obtruction (T0), with 3 hours of obstruction (T3) and 6, 30, 102 and 174 hours after desobstructing (T6, T30, T102 and T174, respectively). Total protein levels were determined by the biuret method and protein fractions were obtained by SDS-PAGE electrophoresis. The acute phase proteins (APP) identified were Immunoglobulin-A, ceruloplasmin, transferrin, albumin, α1-antitrypsin, heavy and light chains of immunoglobulin-G, haptoglobin, α1-acid glycoprotein and a still unnamed protein, which was called P24. There was no difference (P>0.3) in protein levels among groups, although a significant difference (P>0.05) was observed between distinct experimental moments in each group evidencing a higher response of the APP in the obstructed groups. The APP fractioning of the peritoneal liquid was standardized to establish a standard curve for healthy equines and those submitted to induced intestinal obstruction. Moreover, it was verified that the SDS-PAGE electrophoresis was sensitive and effective to help diagnose abdominal inflammatory processes.

scholarly journals Reinvestigation of the dysbindin subunit of BLOC-1 (biogenesis of lysosome-related organelles complex-1) as a dystrobrevin-binding protein

2006 ◽  
Vol 395 (3) ◽  
pp. 587-598 ◽  
Author(s):  
Ramin Nazarian ◽  
Marta Starcevic ◽  
Melissa J. Spencer ◽  
Esteban C. Dell'Angelica
Keyword(s):  
Recombinant Proteins ◽  
Binding Protein ◽  
Coiled Coil ◽  
Direct Interaction ◽  
Muscle Pathology ◽  
Binding Assays ◽  
Genetic Studies ◽  
Binding Interface ◽  
Lysosome Related Organelles

Dysbindin was identified as a dystrobrevin-binding protein potentially involved in the pathogenesis of muscular dystrophy. Subsequently, genetic studies have implicated variants of the human dysbindin-encoding gene, DTNBP1, in the pathogeneses of Hermansky–Pudlak syndrome and schizophrenia. The protein is a stable component of a multisubunit complex termed BLOC-1 (biogenesis of lysosome-related organelles complex-1). In the present study, the significance of the dystrobrevin–dysbindin interaction for BLOC-1 function was examined. Yeast two-hybrid analyses, and binding assays using recombinant proteins, demonstrated direct interaction involving coiled-coil-forming regions in both dysbindin and the dystrobrevins. However, recombinant proteins bearing the coiled-coil-forming regions of the dystrobrevins failed to bind endogenous BLOC-1 from HeLa cells or mouse brain or muscle, under conditions in which they bound the Dp71 isoform of dystrophin. Immunoprecipitation of endogenous dysbindin from brain or muscle resulted in robust co-immunoprecipitation of the pallidin subunit of BLOC-1 but no specific co-immunoprecipitation of dystrobrevin isoforms. Within BLOC-1, dysbindin is engaged in interactions with three other subunits, named pallidin, snapin and muted. We herein provide evidence that the same 69-residue region of dysbindin that is sufficient for dystrobrevin binding in vitro also contains the binding sites for pallidin and snapin, and at least part of the muted-binding interface. Functional, histological and immunohistochemical analyses failed to detect any sign of muscle pathology in BLOC-1-deficient, homozygous pallid mice. Taken together, these results suggest that dysbindin assembled into BLOC-1 is not a physiological binding partner of the dystrobrevins, likely due to engagement of its dystrobrevin-binding region in interactions with other subunits.

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