0000000000261773
AUTHOR
Jasminka Godovac-zimmermann
showing 12 related works from this author
Correlations in palmitoylation and multiple phosphorylation of rat bradykinin B2 receptor in Chinese hamster ovary cells.
1999
Rat bradykinin B2 receptor from unstimulated Chinese hamster ovary cells transfected with the corresponding cDNA has been isolated, and subsequent mass spectrometric analysis of multiple phosphorylated species and of the palmitoylation attachment site is described. Bradykinin B2 receptor was isolated on oligo(dT)-cellulose using N-(epsilon-maleimidocaproyloxy)succinimide-Met-Lys-bradykinin coupled to a protected (dA)30-mer. This allowed a one-step isolation of the receptor on an oligo(dT)-cellulose column via variation solely of salt concentration. After enzymatic in-gel digestion, matrix-assisted laser desorption ionization and electrospray ion trap mass spectrometric analysis of the isola…
8-N(3)-3'-biotinyl-ATP, a novel monofunctional reagent: differences in the F(1)- and V(1)-ATPases by means of the ATP analogue.
2001
A novel photoaffinity label, 8-N(3)-3'-biotinyl-ATP, has been synthesized. The introduction of an additional biotin residue is advantageous for easy detection of labeled proteins. This could be first tested by reaction with the F(1)-ATPase from the thermophilic bacterium PS3 (TF(1)). UV irradiation of TF(1) in the presence of 8-N(3)-3'-biotinyl-ATP results in a nucleotide-dependent binding of the analogue in the noncatalytic alpha and the catalytic beta subunits of TF(1), demonstrating the suitability of this analogue as a potential photoaffinity label. Reaction with the V(1)-ATPase, however, led to labeling of subunit E, which has been suggested as a structural and functional homologue of …
Identification of Purine Binding Sites on Torpedo Acetylcholine Receptor
1994
Electrophysiological studies from this and other laboratories have suggested a direct action of ATP on nicotinic acetylcholine receptors (nAChR). To determine the site of binding of this purine derivative, we have covalently modified the nAChR from Torpedo marmorata electrocytes employing 2-[3H]-8-azido-ATP as a photoactivable affinity label. Covalently attached radioactivity was predominantly found in the beta-polypeptide of the receptor. Based on the results of protection studies with several nAChR ligands whose target sites at the receptor are known, we conclude that the purine site(s) differ from those of acetylcholine and of physostigmine, galanthamine and related ligands, and those of…
Identification of an endothelial cell binding site on kininogen domain D3
1995
High and low molecular mass kininogen, two multidomain plasma proteins, bind to endothelial cells, platelets, and neutrophils in the intravascular compartment. The specific cell attachment site on their common heavy chain is mediated by domain-3, a cystatin-like structure with inhibitory capacity for papain-like proteinases (Jiang, Y., Müller-Esterl, W., and Schmaier, A. H. (1992) J. Biol. Chem. 267, 3712-3717). In this report, the domain-3 cell binding site is determined by an antibody-directed strategy. The epitope of monoclonal antibody HKH15, which binds to domain-3 and blocks the binding of kininogens to platelets and endothelial cells, was mapped using seven synthetic peptides, which …
Photoaffinity labeling of Torpedo acetylcholine receptor by physostigmine.
1993
The plant alkaloid physostigmine, an established anti-cholinesterase agent of the carbamate type, has recently been shown to bind to the nicotinic acetylcholine receptor from Torpedo marmorata electrocytes [Okonjo, K. O., Kuhlmann, J.Maelicke, A. (1991) Eur. J. Biochem. 200, 671-677]. Pharmacological studies of physostigmine-induced ion flux into nicotinic-acetylcholine-receptor-rich membrane vesicles, indicated distinct binding sites for physostigmine and acetylcholine. As shown in this study by photoaffinity labeling with [phenyl-(n)-3H](-)physostigmine, the physostigmine-binding site is located within the same subunit (alpha polypeptide) of the receptor as the acetylcholine-binding site.…
Posttranslational Processing of Human α2-HS Glycoprotein (Human Fetuin)
2008
α2-HS glycoprotein (α2-HS) is a major protein occuring in human blood and calciferous tissues. Due to extensive sequence identity, α2-HS has been grouped with the fetuins, a family of proteins that occur in fetal plasma in high concentrations. Native α2-HS undergoes a series of posttranslational modifications including proteolytic processing, multiple N-glycosylations and O-glycosylations, and sulfation of the carbohydrate side chains. Various two-chain forms of α2-HS have been prepared from human plasma, however, the single-chain precursor has not yet been isolated. Here, we have studied the biosynthesis of α2-HS by a human hepatoma cell line, HepG2. We demonstrate that a single-chain form…
Isolation of the Endothelin B Receptor from Bovine Lung Structure, Signal Sequence, and Binding Site
1995
Bovine lung endothelin-B receptor has been isolated in good yield with a new procedure involving the use of endothelin-1 coupled to iminobiotin with a long spacer and avidin-agarose affinity chromatography. Contrary to previous reports, evidence has been obtained that the native form of this receptor corresponds to the full-length transcript expected on the basis of cDNA clones. The binding of endothelin to a variety of shortened fragments of the full receptor suggests that the long N-terminal sequence of this receptor has very little influence on the binding of endothelin and that the main determinants of the endothelin binding site might be constituted by residues in the sixth, and possib…
Mapping of a binding site for ATP within the extracellular region of the Torpedo nicotinic acetylcholine receptor beta-subunit.
1997
Using 2,8,5'-[H-3]ATP as a direct photoaffinity label for membrane-bound nicotinic acetylcholine receptor (nAChR) from Torpedo marmorata, we have identified a binding site for ATP in the extracellular region of the beta-subunit of the receptor. Photolabeling was completely inhibited in the presence of saturating concentrations of nonradioactive ATP, whereas neither the purinoreceptor antagonists suramin, theophyllin, and caffeine nor the nAChR antagonists alpha-bungarotoxin and d-tubocurarine affected the labeling reaction. Competitive and noncompetitive nicotinic agonists and Ca2+ increased the yield of the photoreaction by up to 50%, suggesting that the respective binding sites are allost…
Isolation of endothelin A receptor from bovine lungs.
1995
We isolated endothelin receptor A (ET A ) from bovine lungs in a single-step purification procedure using antibodies raised against synthetic peptides that correspond to extra- and intracellular domains of the rat bradykinin receptor. Two receptor species of 55 and 35 kDa were isolated and subjected to N-terminal microsequencing. The difference between the observed and expected molecular weight species suggests that bovine ET A receptor is glycosylated.
Physostigmine and Neuromuscular Transmission
1993
Single channel studies carried out in cultured rat myoballs and cultured hippocampal neurons, and ion flux studies performed on Torpedo electrocyte membrane vesicles, showed that physostigmine (Phy), a well-established acetylcholinesterase inhibitor, interacts directly with nicotinic acetylcholine receptors (nAChR). Low concentrations (0.1 microM) of Phy activate the receptor integral channel, whereas higher concentrations blocked the channel in its opened state. In contrast to channel activation by acetylcholine (ACh) and classical cholinergic agonists, however, Phy was capable of activating the nAChR channel even when the ACh binding sites were blocked by competitive antagonists, such as …
Posttranslational processing of human alpha 2-HS glycoprotein (human fetuin). Evidence for the production of a phosphorylated single-chain form by he…
1994
alpha 2-HS glycoprotein (alpha 2-HS) is a major protein occurring in human blood and calciferous tissues. Due to extensive sequence identity, alpha 2-HS has been grouped with the fetuins, a family of proteins that occur in fetal plasma in high concentrations. Native alpha 2-HS undergoes a series of posttranslational modifications including proteolytic processing, multiple N-glycosylations and O-glycosylations, and sulfation of the carbohydrate side chains. Various two-chain forms of alpha 2-HS have been prepared from human plasma, however, the single-chain precursor has not yet been isolated. Here, we have studied the biosynthesis of alpha 2-HS by a human hepatoma cell line, HepG2. We demon…
Expression and renaturation of the N-terminal extracellular domain of torpedo nicotinic acetylcholine receptor alpha-subunit.
1998
The N-terminal extracellular region (amino acids 1-209) of the alpha-subunit of the nicotinic acetylcholine receptor (nAChR) from Torpedo marmorata electric tissue was expressed as inclusion bodies in Escherichia coli using the pET 3a vector. Employing a novel protocol of unfolding and refolding, in the absence of detergent, a water-soluble globular protein of 25 kDa was obtained displaying approximately 15% alpha-helical and 45% beta-structure. The fragment bound alpha-[3H]bungarotoxin in 1:1 stoichiometry with a KD value of 0.5 nM as determined from kinetic measurements (4 nM from equilibrium binding). The kinetics of association of toxin and fragment were of second order, with a similar …