Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.4.2.30 (PARP)
13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 22 kDa protein substrate of botulinum ADP-ribosyltransferase C3 was purified from porcine brain cytosol by acetone precipitation, CM-Sephadex, octyl-Sepharose and TSK phenyl-5PW HPLC chromatography to apparent homogeneity. ADP-ribosylation of the protein was increased by guanine nucleotides (GTP, GDP, GTP gamma S, each 100 microM) but not by GMP, ATP or ATP gamma S. The purified 22 kDa protein bound maximally 0.9 mol [35S]GTP gamma S and hydrolyzed GTP with the rate 0.007 mol per mol protein. Amino acid sequences were obtained from two tryptic peptides, selected from an in situ digestion of Immobilon electrotransferred, gel purified ADP-ribosylated substrate. The two sequences obtained, cover 23 residues from the corresponding sequences in human rho.
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PMID:Purification of the 22 kDa protein substrate of botulinum ADP-ribosyltransferase C3 from porcine brain cytosol and its characterization as a GTP-binding protein highly homologous to the rho gene product. 249 91

The interaction of nucleotides with pertussis toxin (PT), and their effects on the ability of the toxin to ADP-ribosylate pure Ni, were evaluated. [32P]ATP (10 nM) bound directly to dithiothreitol-activated PT. This binding was competitively inhibited by nucleotides and anions with the following IC50 concentrations in order of decreasing potency: ATP = ATP gamma S (adenosine-5'-O-(3-thiotriphosphate)) = 0.2-0.3 microM, GDP beta S (guanosine-5'-O-(2-thiodiphosphate)) = 2-3 microM, GTP gamma S (guanosine-5'-O-(3-thiotriphosphate)) = 10-15 microM, ADP = 20-25 microM, GTP = 30-40 microM, GMP-P(NH)P (guanyl-5'-yl imidodiphosphate) = 100-150 microM, GDP = 150-200 microM, Pi = SO4(2-) = 20 mM and Cl- = acetate = 30-35 mM. Treatment of PT with ATP, AMP-P(NH)P, GTP, GDP, or GDP beta S, resulted in a stimulated state of NAD+-Ni ADP-ribosyltransferase activity. Addition of ATP, AMP-P(NH)P (adenyl-5'-yl imidodiphosphate), GTP, GDP, and GDP beta S to the ADP-ribosylation reactions resulted in increased rates of ADP-ribosyl-Ni formation. It is concluded that these effects on the nucleotides are due to their action to stimulate the activity of PT. At concentrations of PT between 0.04 and 0.4 microgram/ml, the stimulation of ADP-ribosylation of Ni effected by nucleotides was hysteretic in nature, exhibiting an approximately 25-min long lag when GDP was used as the activating nucleotide. These lags decreased with increasing concentrations of PT, and were abolished by pretreatment of the toxin with GDP or ATP. Preliminary incubation of Ni with GDP had no effect on the lag in its ADP-ribosylation by non-nucleotide treated PT. Addition of divalent cations (Mg2+, Mn2+, and Ca2+) inhibited formation of ADP-ribosyl-Ni, possibly by causing aggregation and denaturation of Ni. This is the first demonstration that both adenine and guanine nucleotides interact directly with PT and act to stimulate its activity to ADP-ribosylate Ni, and that guanine nucleotides do so regardless of whether they are nucleoside di- or triphosphates.
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PMID:The interaction of nucleotides with pertussis toxin. Direct evidence for a nucleotide binding site on the toxin regulating the rate of ADP-ribosylation of Ni, the inhibitory regulatory component of adenylyl cyclase. 309 44

The effect of the addition of guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S), the GTP analog which activates the inhibitory guanine nucleotide-binding regulatory protein of adenylyl cyclase (Ni), on the pertussis toxin-mediated ADP-ribosylation reaction was studied in detail. Two effects were discerned: a stimulation of the ADP-ribosyltransferase activity of the toxin, akin to what was described for ATP and GDP in a previous report (Mattera, R., Codina, J., Sekura, R., and Birnbaumer, L. (1986) J. Biol. Chem. 261, 11173-11179), and a decrease in the ability of Ni to be a substrate for the activated toxin. Both effects were time-dependent with activation of the toxin being somewhat faster than inactivation of Ni. The effect of the addition of GTP gamma S on Ni was readily reversed by excess GDP and attenuated by increasing EDTA in the medium from 0.35 to 10 mM, suggesting dependence on trace concentrations of a divalent cation. It is suggested that this cation is Mg2+ on the basis that low (5-10 nM) concentrations of Mg2+ are needed for the endogenous GTPase activity of Ni (Sunyer, T., Codina, J., and Birnbaumer, L. (1984) J. Biol. Chem. 259, 15447-15451). Sucrose density gradient analysis of the Ni X GTP gamma S complexes with decreased susceptibility to ADP-ribosylation by pertussis toxin showed the same sedimentation parameters as Ni or Ni X GDP complexes, indicating that the molecule of Ni with GTP gamma S bound is heterotrimetric as opposed to dissociated into alpha i X GTP gamma S plus beta X gamma. Thus, these experiments define two conformations of heterotrimeric Ni: one -pt+, ADP-ribosylated by pertussis toxin, and the other pt-, poorly or not ADP-ribosylated by pertussis toxin. This latter, hitherto unrecognized conformation, is stabilized by the addition of strongly activating guanine nucleotides such as GTP gamma S and guanyl-5'-yl imidodiphosphate and should be important in the train of events that lead from an inactive heterotrimeric Ni to a fully active and dissociated Ni.
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PMID:Guanosine 5'-O-(3-thiotriphosphate) reduces ADP-ribosylation of the inhibitory guanine nucleotide-binding regulatory protein of adenylyl cyclase (Ni) by pertussis toxin without causing dissociation of the subunits of Ni. Evidence of existence of heterotrimeric pt+ and pt- conformations of Ni. 311 55

A novel ADP-ribosyltransferase C3 was purified to homogeneity from filtrates of certain strains of Clostridium botulinum type C by ammonium sulfate precipitation, gel filtration, ion-exchange chromatography and heat treatment. The molecular mass of botulinum ADP-ribosyltransferase C3 was found to be 25 kDa. In the presence of [32P]NAD but not with [carbonyl-14C]NAD, C3 labelled 21-24-kDa protein(s) in membranes of human platelets and other tissues. The Km value of the ADP-ribosylation reaction for NAD was about 2 microM. Labelling of the 21-24-kDa protein(s) by C3 was largely reduced by addition of nicotinamide. Snake venom phosphodiesterase cleaved the ADP-ribose attached to the 21-24-kDa protein(s) by C3 and released 5'AMP. C3 catalyzed hydrolysis of [carbonyl-14C]NAD and released [carbonyl-14C]nicotinamide. ADP-ribosylation of 21-24-kDa platelet membrane protein(s) was biphasically regulated by Mg2+, Mn2+ and Ca2+. In the absence of free divalent cations GTP, GTP[gamma S] and GDP but not GDP[beta S], GMP, ATP or ATP[gamma S] increased labelling by C3. In the presence of Mg2+, GTP[gamma S] was inhibitory. Guanine nucleotides prevented heat inactivation of the substrate protein(s) with the rank order GTP[gamma S] = GTP = GDP greater than GDP[beta S] greater than GMP much greater than ATP = GMP = ATP[gamma S]. The data support the view that the novel ADP-ribosyltransferase C3 modifies eukaryotic 21-24-kDa GTP-binding protein(s).
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PMID:Botulinum ADP-ribosyltransferase C3. Purification of the enzyme and characterization of the ADP-ribosylation reaction in platelet membranes. 312 9

The substrate for ADP-ribosyltransferase from Clostridium botulinum was purified from the cytosol of bovine adrenal gland. Purification procedures consisted of ammonium sulfate fractionation, chromatographies on columns of DEAE-Sepharose and phenyl-Sepharose, gel filtration on a TSK-gel G3000SW column, and Mono Q fast protein liquid chromatography. On DEAE-Sepharose chromatography, the substrate activity was eluted in two separate peaks, and electrophoretic analyses revealed that the substrates in the two peaks are of similar molecular weight but different isoelectric points. The major peak of the substrate was further purified. It was purified about 1,800-fold with a recovery of 2.2% by the above procedures. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the final preparation showed a single protein band at Mr 22,000. The purified protein served as a substrate for botulinum ADP-ribosyltransferase and was maximally ADP-ribosylated to the extent of about 0.7 mol of ADP-ribose/mol of protein. A guanosine 5'-(3-O-thio)triphosphate (GTP gamma S) binding activity was co-purified with the ADP-ribosylation substrate, and the purified protein maximally bound about 0.5 mol of GTP gamma S/mol. GTP gamma S binding was effectively competed by GTP and GDP but not by GMP, ATP, and ADP. Thus, the ADP-ribosylation substrate is a GTP-binding protein. This protein, designated Gb (b for botulinum), is widely distributed in various tissues. It was rich in brain, pituitary, and adrenal glands, and poor in heart, smooth, and skeletal muscles.
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PMID:Purification and properties of the cytosolic substrate for botulinum ADP-ribosyltransferase. Identification as an Mr 22,000 guanine nucleotide-binding protein. 313 28

Triton X-114 phase partitioning, a procedure used for purifying integral membrane proteins, was used to study protein components of the mammalian visual transduction cascade. An integral membrane protein, rhodopsin, and two isoprenylated protein complexes, cyclic GMP phosphodiesterase and Gt beta gamma, partitioned into the detergent-rich phase. Arrestin, a soluble protein, accumulated in the aqueous phase. Gt alpha distributed about equally between phases whether GDP (Gt alpha.GDP) or GTP (Gt alpha.GTP) was bound. Gt beta gamma increased recovery of Gt alpha.GDP but not Gt alpha.GTP in the detergent phase. Trypsin-treated Gt alpha, which lacks the fatty acylated amino-terminal 2-kDa region, accumulated to a greater extent in the aqueous phase than did intact Gt alpha. Trypsinized cGMP phosphodiesterase, which lacks the isoprenyl group, partitioned into the aqueous phase. A carboxyl-terminal truncated mutant (Val-331 stop) of Gt alpha accumulated more in the aqueous phase then did recombinant full-length Gt alpha, supporting the role of the carboxyl terminus in increasing its hydrophobicity. N-Myristoylated recombinant Go alpha was more hydrophobic than recombinant Go alpha without myristate. ADP-ribosylation of Gt alpha catalyzed by NAD:arginine ADP-ribosyltransferase, but not by pertussis toxin, increased hydrophilicity. Triton X-114 phase partitioning can thus semiquantify the hydrophobic nature of proteins and protein domains. It may aid in evaluating changes associated with post-translational protein modification and protein-protein interactions in a defined system.
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PMID:Hydrophobicity and subunit interactions of rod outer segment proteins investigated using Triton X-114 phase partitioning. 762 4

ADP-ribosylation factors (ARFs) are approximately 20-kDa guanine nucleotide-binding proteins that activate cholera toxin ADP-ribosyltransferase in vitro and participate in intracellular vesicular membrane trafficking. ARFs are activated when bound GDP is replaced by GTP and inactivated by hydrolysis of bound GTP to yield ARF-GDP. Usually, ARFs are isolated in an inactive GDP-bound state and require addition of GTP along with detergent or phospholipid for activity. Purified mutant recombinant ARF1 lacking the first 13 amino acids (r delta 13ARF1-P) stimulated cholera toxin activity essentially equally with or without added GTP (and phospholipid or detergent), at least in part due to the presence of bound nucleotides, which later were identified as GTP and GDP. Nucleotide-free r delta 13ARF1 (r delta 13ARF1-F), prepared by dialysis against 7 M urea, was active without added GTP in the absence of SDS but inactive without added GTP in its presence. Renaturation of r delta 13ARF1-F in the presence of GTP, ITP, or GDP yielded, respectively, r delta 13ARF1-GTP and r delta 13ARF1-ITP, which were active, and r delta 13ARF1-GDP, which was inactive. Effects of phospholipids and detergents on nucleotide exchangeability evaluated as effects on activity of rARF1 and r delta 13ARF1-F differed. With r delta 13ARF1-F, 100 microM ITP and 100 microM GTP were essentially equally effective in the presence of cardiolipin or SDS. The finding that r delta 13ARF1 differs from rARF1 in the effects of phospholipids and detergents on nucleotide binding is consistent with the conclusion that the ARF amino terminus plays an important role in nucleotide binding and its specificity as well as the molecular conformation and associated activity.
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PMID:Isolation of an amino-terminal deleted recombinant ADP-ribosylation factor 1 in an activated nucleotide-free state. 770 74

ADP-ribosylation factors (ARFs) are approximately 20-kDa guanine nucleotide-binding proteins that participate in vesicular transport in the Golgi and other intracellular compartments and stimulate cholera toxin ADP-ribosyltransferase activity. ARFs are active in the GTP-bound form; hydrolysis of bound GTP to GDP, possibly with the assistance of a GTP hydrolysis (GTPase)-activating protein results in inactivation. Exchange of GDP for GTP and reactivation were shown by other workers to be enhanced by Golgi membranes in a brefeldin A-sensitive reaction, leading to the proposal that the guanine nucleotide-exchange protein (GEP) was a target of brefeldin A. In the studies reported here, a soluble GEP was partially purified from bovine brain. Exchange of nucleotide on ARFs 1 and 3, based on increased ARF activity in a toxin assay and stimulation of binding of guanosine 5'-[gamma-[35S]thio]triphosphate, was dependent on phospholipids, with phosphatidylserine being more effective than cardiolipin. GEP appeared to increase the rate of nucleotide exchange but did not affect the affinity of ARF for GTP. Whereas the crude GEP had a size of approximately 700 kDa, the partially purified GEP behaved on Ultrogel AcA 54 as a protein of 60 kDa. With purification, the GEP activity became insensitive to brefeldin A, consistent with the conclusion that, in contrast to earlier inferences, the exchange protein is not itself the target of brefeldin A.
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PMID:Identification of a brefeldin A-insensitive guanine nucleotide-exchange protein for ADP-ribosylation factor in bovine brain. 815 7

Brefeldin A (BFA) is a fungal metabolite that exerts profound and generally inhibitory actions on membrane transport. At least some of the BFA effects are due to inhibition of the GDP-GTP exchange on the ADP-ribosylation factor (ARF) catalyzed by membrane protein(s). ARF activation is likely to be a key event in the association of non-clathrin coat components, including ARF itself, onto transport organelles. ARF, in addition to participating in membrane transport, is known to function as a cofactor in the enzymatic activity of cholera toxin, a bacterial ADP-ribosyltransferase. In this study we have examined whether BFA, in addition to inhibiting membrane transport, might affect endogenous ADP-ribosylation in eukaryotic cells. Two cytosolic proteins of 38 and 50 kDa were enzymatically ADP-ribosylated in the presence of BFA in cellular extracts. The 38-kDa substrate was tentatively identified as the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase. The BFA-binding components mediating inhibition of membrane traffic and stimulation of ADP-ribosylation appear to have the same ligand specificity. These data demonstrate the existence of a BFA-sensitive mono(ADP-ribosyl)transferase that may play a role in membrane movements.
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PMID:Stimulation of endogenous ADP-ribosylation by brefeldin A. 830 39

Four monoclonal antibodies that inhibited ADP-ribosylation of 23 kDa protein(s) of ascidian eggs catalyzed by Clostridium botulinum ADP-ribosyltransferase C3 were produced. They also inhibited C3-catalyzed ADP-ribosylation of the 24 kDa protein of rat liver cytosol. By the immunoprecipitation technique, it was found that they recognized small GTP-binding proteins of ascidian eggs and mammalian brains, but did not interact with the rat brain activator of the ADP-ribosyltransferase reaction. The antibody can also immunoprecipitate recombinant Rho A irrespective as to whether the Rho A is the GDP-bound form or the GTPrS-bound form. Thus the antibodies are novel and useful tools in analyzing the physiological roles of the Rho family of GTP-binding proteins.
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PMID:Production of monoclonal antibodies that inhibit ADP-ribosylation of small GTP-binding proteins catalyzed by Clostridium botulinum ADP-ribosyltransferase C3. 840 81


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