Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gonad-stimulating substance (GSS) secreted from radial nerves induces meiotic maturation of starfish oocytes by stimulating production of 1-methyladenine (1-MeAde) in ovarian follicle cells. We have previously shown that cAMP mediates the action of GSS on 1-MeAde synthesis by starfish ovarian follicle cells. The present study examines the possible involvement of guanine nucleotide-binding regulatory proteins (G-proteins) and adenylate cyclase in the action of GSS on 1-MeAde production by starfish (Asterina pectinifera) follicle cells. GSS slightly stimulated adenylate cyclase activity in crude membrane preparations of follicle cells. GTP markedly enhanced this action of GSS in a dose-dependent manner. Nonhydrolyzable GTP analogs such as guanosine 5'-O-(3-thiotriphosphate) and 5'-guanylylimidodiphosphate, NaF, and forskolin also stimulated adenylate cyclase activity. In addition, chorela toxin (CT) stimulated adenylate cyclase activity in membrane preparations in the presence of NAD and GTP. Unlike adenylate cyclase, phosphodiesterase activity was not influenced by GSS. When crude membranes of follicle cells were incubated with [alpha-32P]NAD in the presence of CT and pertussis toxin, 45-kDa and 41-kDa proteins were ADP-ribosylated, respectively, suggesting the presence of two types (stimulatory and inhibitory) of G-proteins. It is concluded that G-proteins and adenylate cyclase play an important role in the action of GSS on 1-MeAde production by starfish ovarian follicle cells.
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PMID:Involvement of G-proteins and adenylate cyclase in the action of gonad-stimulating substance on starfish ovarian follicle cells. 184 1

Trypsin digestion of pertussis toxin (PT) preferentially cleaved the S1 subunit at Arg-218 without detectable degradation of the B oligomer. The fragment produced, termed the tryptic S1 fragment, appears to remain associated with the B oligomer. Chymotrypsin digestion of PT also preferentially cleaved the S1 subunit without detectable degradation of the B oligomer. The chymotryptic S1 fragment possessed a slightly lower apparent molecular weight than the tryptic S1 fragment and was more accessible to the respective protease. Trypsin- and chymotrypsin-treated PT and PT required the presence of dithiothreitol and ATP for optimal enzymatic activity. Trypsin-treated PT showed approximately a 2-4-fold higher level of expression of ADP-ribosyltransferase and NAD-glycohydrolase activities than PT. Chymotrypsin-treated PT also exhibited approximately a 2-fold greater level of ADP-ribosyltransferase activity than PT. The observed increase in activity of protease-treated PT was due primarily to a shorter time for activation in PT mediated ADP-ribosylation of transducin. In addition, trypsin-digested PT possessed the same cytotoxic potential for Chinese hamster ovary cell clustering as PT. One possible role for the generation of a proteolytic fragment of the S1 subunit of PT would be to produce a catalytic fragment with increased efficiency for ADP-ribosylation of G proteins in vivo.
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PMID:Protease treatment of pertussis toxin identifies the preferential cleavage of the S1 subunit. 185 Jul 38

Few receptor-mediated phenomena have been detected in peripheral nerve. In this study, the ability of the muscarinic cholinergic receptor agonist carbamylcholine to enhance phosphoinositide (PPI) breakdown in sciatic nerve was investigated by measuring the accumulation of inositol phosphates. Rat sciatic nerve segments were prelabeled with myo-[3H]inositol and then incubated either with or without carbamylcholine in the presence of Li+. [3H]Inositol monophosphate ([3H]IP) accumulation contained most of the radioactivity in inositol phosphates, with [3H]inositol bisphosphate ([3H]IP2) and [3H]inositol trisphosphate ([3H]IP3) accounting for 7-8% and 1-2% of the total, respectively. In the presence of 100 microM carbamylcholine, [3H]IP accumulation increased by up to 150% after 60 min. The 50% effective concentration for the response was determined to be 20 microM carbamylcholine and stimulated IP generation was abolished by 1 microM atropine. Enhanced accumulation of IP2 and IP3 was also observed. Determination of the pA2 values for the muscarinic receptor antagonists atropine (8.9), pirenzepine (6.5), AF-DX 116 (11-[[2-[(diethylamino)methyl]-1-piperidinyl] acetyl]-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one) (5.7), and 4-diphenylacetoxy-N-methylpiperidinemethiodide (4-DAMP) (8.6) strongly suggested that the M3 muscarinic receptor subtype was predominantly involved in mediating enhanced PPI degradation. Following treatment of nerve homogenates and myelin-rich fractions with pertussis toxin and [32P]NAD+, the presence of an ADP-ribosylated approximately 40-kDa protein could be demonstrated. The results indicate that peripheral nerve contains key elements of the molecular machinery needed for muscarinic receptor-mediated signal transduction via the phosphoinositide cycle.
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PMID:Muscarinic cholinergic receptor-mediated phosphoinositide metabolism in peripheral nerve. 185 Dec 6

Adenylate cyclase activity in isolated rat liver plasma membranes was inhibited by NADH in a concentration-dependent manner. Half-maximal inhibition of adenylate cyclase was observed at 120 microM concentration of NADH. The effect of NADH was specific since adenylate cyclase activity was not altered by NAD+, NADP+, NADPH, and nicotinic acid. The ability of NADH to inhibit adenylate cyclase was not altered when the enzyme was stimulated by activating the cyclase was not altered when the enzyme was stimulated by activating the Gs regulatory element with either glucagon or cholera toxin. Similarly, inhibition of Gi function by pertussis toxin treatment of membranes did not attenuate the ability of NADH to inhibit adenylate cyclase activity. Inhibition of adenylate cyclase activity to the same extent in the presence and absence of the Gpp (NH) p suggested that NADH directly affects the catalytic subunit. This notion was confirmed by the finding that NADH also inhibited solubilized adenylate cyclase in the absence of Gpp (NH)p. Kinetic analysis of the NADH-mediated inhibition suggested that NADH competes with ATP to inhibit adenylate cyclase; in the presence of NADH (1 mM) the Km for ATP was increased from 0.24 +/- 0.02 mM to 0.44 +/- 0.08 mM with no change in Vmax. This observation and the inability of high NADH concentrations to completely inhibit the enzyme suggest that NADH interacts at a site(s) on the enzyme to increase the Km for ATP by 2-fold and this inhibitory effect is overcome at high ATP concentrations.
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PMID:Inhibition of hepatic adenylate cyclase by NADH. 187

Five ADP-ribosylating bacterial toxins, pertussis toxin, cholera toxin, diphtheria toxin, Escherichia LT toxin and Pseudomonas exotoxin A, show significant homology in selected segments of their sequence. Site-directed mutagenesis and chemical modification of residues within these regions cause loss of catalytic activity and of NAD binding. On the basis of these results and of molecular modelling based on the three-dimensional structure of exotoxin A, the geometry of an NAD binding site common to all the toxins is deduced and described in the paper. For diphtheria toxin, sequence similarity with exotoxin A is such that its preliminary structure can be computed by molecular modelling, whereas for the other toxins similarity appears to be restricted to the NAD binding site. Moreover, an analysis of molecular fitting of the NAD molecule into its binding cavity suggests a new model for the conformation of the bound NAD that better accounts for all available experimental information.
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PMID:Computer modelling of the NAD binding site of ADP-ribosylating toxins: active-site structure and mechanism of NAD binding. 190 17

Following a previous report on detection of muscarinic receptors in myelin with the implied presence of G proteins, we now demonstrate by more direct means the presence of such proteins and their quantification. Using [35S]guanosine 5'-O-(3-thiotriphosphate) ([35S]GTP gamma S) as the binding ligand, purified myelin from bovine brain was found to contain approximately half the binding activity of whole white matter (138 +/- 9 vs. 271 +/- 18 pmol/mg of protein). Scatchard analysis of saturation binding data revealed two slopes, a result suggesting at least two binding populations. This binding was inhibited by GTP and its analog but not by 5'-adenylylimidodiphosphate [App(NH)p], GMP, or UTP. Following sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) of myelin proteins and blotting on nitrocellulose, [alpha-32P]GTP bound to three bands in the 21-27-kDa range in a manner inhibited by GTP and GTP gamma S but not App(NH)p. ADP-ribosylation of myelin with [32P]NAD+ and cholera toxin labeled a protein of 43 kDa, whereas reaction with pertussis toxin labeled two components of 40 kDa. Cholate extract of myelin subjected to chromatography on a column of phenyl-Sepharose gave at least three major peaks of [35S]GTP gamma S binding activity. SDS-PAGE and immunoblot analyses of peak I indicated the presence of Go alpha, Gi alpha, and Gs alpha. Further fractionation of peak II by diethyl-aminoethyl-Sephacel chromatography gave one [35S]GTP gamma S binding peak with the low-molecular-mass (21-27 kDa) proteins and a second showing two major protein bands of 36 and 40 kDa on SDS-PAGE.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Detection of G proteins in purified bovine brain myelin. 190 10

Previous studies of the S1 subunit of pertussis toxin, an NAD(+)-dependent ADP-ribosyltransferase, suggested that a small amino-terminal region of amino acid sequence similarity to the active fragments of both cholera toxin and Escherichia coli heat-labile enterotoxin represents a region containing critical active-site residues that might be involved in the binding of the substrate NAD+. Other studies of two other bacterial toxins possessing ADP-ribosyltransferase activity, diphtheria toxin and Pseudomonas exotoxin A, have revealed the presence of essential glutamic acid residues vicinal to the active site. To help determine the relevance of these observations to activities of the enterotoxins, the A-subunit gene of the E. coli heat-labile enterotoxin was subjected to site-specific mutagenesis in the region encoding the amino-terminal region of similarity to the S1 subunit of pertussis toxin delineated by residues 6 through 17 and at two glutamic acid residues, 110 and 112, that are conserved in the active domains of all of the heat-labile enterotoxin variants and in cholera toxin. Mutant proteins in which arginine 7 was either deleted or replaced with lysine exhibited undetectable levels of ADP-ribosyltransferase activity. However, limited trypsinolysis of the arginine 7 mutants yielded fragmentation kinetics that were different from that yielded by the wild-type recombinant subunit or the authentic A subunit. In contrast, mutant proteins in which glutamic acid residues at either position 110 or 112 were replaced with aspartic acid responded like the wild-type subunit upon limited trypsinolysis, while exhibiting severely depressed, but detectable, ADP-ribosyltransferase activity. The latter results may indicate that either glutamic acid 110 or glutamic acid 112 of the A subunit of heat-labile enterotoxin is analogous to those active-site glutamic acids identified in several other ADP-ribosylating toxins.
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PMID:Effect of site-directed mutagenic alterations on ADP-ribosyltransferase activity of the A subunit of Escherichia coli heat-labile enterotoxin. 190 25

The effects of pertussis toxin (PTX) on synaptosomal tyrosine hydroxylase (TH) activity and on the inhibition of synaptosomal TH activity by apomorphine were investigated. Exposure of striatal synaptosomes to PTX does not affect basal- or forskolin-stimulated TH activity, but attenuates apomorphine-elicited inhibition of forskolin-stimulated synaptosomal TH activity. There is a good correlation between the attenuation of apomorphine-elicited inhibition of synaptosomal TH activity by PTX and (-)-sulpiride, suggesting that G proteins are involved in the dopamine (DA) autoreceptor-mediated regulation of the enzyme activity. The exposure of synaptosome to PTX results in a 40-50% inactivation of Gi and Go proteins, which is evident from the reduction of ADP ribosylation with [32P]NAD of the remaining G proteins following preincubation with the toxin. The present study also demonstrates that striatal synaptosomal preparations can be used for investigations of the molecular properties of nerve terminal DA autoreceptors.
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PMID:Effects of pertussis toxin on inhibition of synaptosomal tyrosine hydroxylase activity by apomorphine. 196 53

Purified recombinant S1 subunit of pertussis toxin (rS1) possessed similar NAD glycohydrolase and ADP-ribosyltransferase activities as S1 subunit purified from pertussis toxin. Purified rS1 and C180 peptide, a deletion peptide which contains amino acids 1-180 of rS1, had Km values for NAD of 24 and 13 microM and kcat values of 22 and 24 h-1, respectively, in the NAD glycohydrolase reaction. In contrast, under linear velocity conditions, the C180 peptide possessed less than 1% of the ADP-ribosyltransferase activity of rS1 using transducin as target. Radiolabeled tryptic peptides of transducin that had been ADP-ribosylated by either rS1 or C180 peptide were identical which suggested that both rS1 and C180 peptide ADP-ribosylated the same amino acid within transducin. To extend the functional primary amino acid map of the S1 subunit, two carboxyl-terminal deletions were constructed. One deletion, C195, removed the 40 carboxyl-terminal amino acids and the other, C219, removed the 16 carboxyl-terminal amino acids of the S1 subunit. Both C195 and C219 migrated in reduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis with apparent molecular masses of 22,000 and 27,500 Da, respectively. Relative to the C180 peptide C195 possessed 10-20-fold increase and C219 possessed 100-150-fold increase in ADP-ribosyltransferase activities. In addition, C219 appeared to have the same ADP-ribosyltransferase activity as rS1. These studies indicate that (i) rS1, purified from Escherichia coli, possesses biochemical properties similar to S1 subunit purified from pertussis toxin, (ii) amino acids 1-180 of the S1 subunit contain residues required for NAD binding, N-glycosidic cleavage, and transfer of ADP-ribose to transducin, and (iii) residues between 181 and 219 of the S1 subunit are required for efficient ADP-ribosyltransferase activity.
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PMID:Localization of a region of the S1 subunit of pertussis toxin required for efficient ADP-ribosyltransferase activity. 199 75

Pertussis toxin (PT) is a major virulence factor of Bordetella pertussis, and also an important protective antigen. PT is an oligomeric A-B type toxin in which the S1 subunit has the ADP-ribosyltransferase activity whereas the B-oligomer mediates its binding to target cell receptors. To analyze the immunological properties of S1 and to generate probes to localize and characterize S1 functional domains, we synthesized four sets of peptides and peptide analogs corresponding to potentially critical regions of the S1 subunit. Two peptide-KLH conjugates were found to be capable of inducing PT-neutralizing antibodies in rabbits as judged by the CHO cell clustering assay. These peptides comprise residues 1-18 (N18-S1) and 121-138 (NAD-S1), respectively. Immunization with the unconjugated C-terminal peptide C35-S1 (residues 201-235) in the presence of Freund's adjuvant also elicited PT-neutralizing antibodies, indicating that the C-terminal region of S1 contains a potent functional T-helper cell epitope. Using truncated peptide analogs of N18-S1, we have demonstrated that the first three N-terminal residues are essential for inducing neutralizing antibodies. The NAD-S1 peptide elicited a neutralizing antibody response when coupled to KLH via its N-terminal end but not via its C-terminal residue. Identification of these B-cell neutralization epitopes represents a first step towards the rational design of a synthetic vaccine against whooping cough.
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PMID:Structural and functional analysis of the S1 subunit of pertussis toxin using synthetic peptides. 201 95


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