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C Wernstedt

Publications and source records attributed to C Wernstedt.

At least 55 records · Page 3Linked to original sources
PubMed1992

Identification of two C-terminal autophosphorylation sites in the PDGF beta-receptor: involvement in the interaction with phospholipase C-gamma.

Two novel sites of autophosphorylation were localized to the C-terminal tail of the PDGF beta-receptor. To evaluate the importance of these phosphorylation sites, receptor mutants in which Tyr1009, Tyr1021 or both were replaced with phenylalanine residues, were expressed in porcine aortic endothelial (PAE) cells. These mutants were similar to the wild type receptor with regard to protein tyrosine kinase activity and ability to induce mitogenicity in response to PDGF-BB. However, both the Y1009F and Y1021F mutants showed a decreased ability to mediate association with and the tyrosine phosphorylation of phospholipase C-gamma (PLC-gamma) compared to the wild type PDGF beta-receptor; in the case of the Y1009F/Y1021F double mutant, no association or phosphorylation of PLC-gamma could be detected. These data show that tyrosine phosphorylation of PLC-gamma is dependent on autophosphorylation of the PDGF beta-receptor at Tyr1009 and Tyr1021.

Amino Acid Sequence↗
PubMed1992

Extremely divergent histone H4 sequence from Trypanosoma cruzi: evolutionary implications.

Trypanosoma cruzi presents six histones electrophoretically resolved in three gel systems. Indirect evidence shows that one of these histones, named e, corresponds to H4 in other species. We present evidence that histone e is H4 by sequencing its amino terminal end. The amino terminal of T. cruzi histone H4, unlike that of other H4s examined thus far is not blocked. Moreover, this protein presents two variants. This partial amino acid sequence of T. cruzi histone H4 differs greatly from homologous sequences of human, yeast, or Tetrahymena. Since the conservatism of the core histones (H2A, H2B, H3, and H4) is clearly illustrated by comparative sequence analyses, the data shown here demonstrates that T. cruzi histone H4 is the most divergent reported. Quantitative analysis of the data suggests that the rate of substitutions in the histone H4 amino terminal sequence varies among different lineages. We postulate a slow-down in the evolutionary rate of histone H4 amino terminal domain in the metazoa branch related perhaps to the appearance of a novel function for this domain.

Amino Acid Sequence↗
PubMed1991

Isolation and characterization of a hemoglobin-derived opioid peptide from the human pituitary gland.

An opioid nonapeptide was isolated from fresh frozen human pituitaries. Its primary structure (Leu-Val-Tyr-Pro-Trp-Thr-Gln-Arg) was identical to fragment 32-40 of the beta-, delta-, gamma- and epsilon-chains of human hemoglobin. A larger peptide of about 4.5 kDa, which generated a fragment containing the nonapeptide on trypsin digestion, showed an amino acid composition similar to fragment 1-41 of the beta-chain of human hemoglobin. The nonapeptide interacted with mu-opioid receptors in rat brain homogenates using [3H]-(D-Ala2, MePhe3, Gly-ol5)-enkephalin and with sigma-receptors using (+)-[3H]-3-(3-hydroxyphenyl)-N-1-(propyl)piperidine, respectively. The affinities for mu-opioid receptors were in the same range as those observed for the structurally related beta-casomorphins. However, the isolated peptide showed markedly higher affinity at sigma-binding sites when compared to the beta-casomorphins or other opioid peptides. The opioid potency of this peptide as determined in the guinea-pig ileum myenteric plexus muscle preparation, was significant but less than that observed for the beta-casomorphins.

Amino Acid Sequence↗
PubMed1991

Amino acid sequence of a snake venom toxin that binds to the muscarinic acetylcholine receptor.

The green mamba, Dendroaspis angusticeps, has two protein toxins that bind to the muscarinic acetylcholine receptor. The sequence of muscarinic toxin 2 was determined with an automatic gas phase sequencer. The C-terminal residue is Asp as determined by hydrazinolysis and amino acid analysis. Toxin 2 has 65 amino acid residues and a formula weight of 7040. It is homologous to a large number of other snake venom toxins as short alpha-neurotoxins, cardiotoxins/cytotoxins and angusticeps-type toxins of mamba venoms. The sequence is confirmed in the accompanying article (Ducancel, F., Rowan, E.G., Cassart, E., Harvey, A. L., Menez, A. and Boulain, J.-C. Toxicon 29, 516-520, 1991).

Amino Acid Sequence↗
PubMed1991

Self-proteolysis of the cysteine proteinase, cruzipain, from Trypanosoma cruzi gives a major fragment corresponding to its carboxy-terminal domain.

The major cysteine proteinase (cruzipain) purified from Trypanosoma cruzi epimastigotes catalyzes its own degradation in the presence of beta-mercaptoethanol, at 56 degrees C and pH 6. The reaction is affected by the same inhibitors which inhibit the azocaseinase activity, and yields a major 25-kDa fragment, which contains carbohydrate, few, if any, aromatic amino acids, and presents a proline-rich N-terminus (GPGPXPEP...), in addition to a number of small peptides, which can be isolated by reversed-phase HPLC, but are lost during electrophoresis. The results, together with recently published evidence of Mottram et al. and Eakin et al., are compatible with a structure for cruzipain consisting of a conventional cysteine proteinase moiety, linked to a long C-terminal extension including the 25-kDa fragment, which would contain a high proportion of the carbohydrate and the proline residues present in the original 60-kDa molecule.

Amino Acid Sequence↗
PubMed1991

Amyloid in the pancreatic islets of the cougar (Felis concolor) is derived from islet amyloid polypeptide (IAPP).

1. Islet amyloid isolated from the pancreas of a 20-year-old cougar (Felis concolor) was dissolved and purified by gel permeation and reversed phase HPLC for amino acid sequence analysis. 2. N-Terminal amino acid sequence analysis of the purified protein revealed a primary structure (positions 1-28) identical to islet amyloid polypeptide (IAPP) from domesticated cats. 3. IAPP from the cougar, like IAPP from the human and domesticated cat, incorporates an inherently amyloidogenic AILS sequence at positions 25-28.

Amino Acid Sequence↗
PubMed1991

The N-terminal amino acid sequence of phenol hydroxylase contains a dinucleotide-binding sequence motif.

The N-terminal sequence of phenol hydroxylase from Trichosporon cutaneum was determined by Edman degradation of the integral protein and of fragments obtained by hydroxylamine cleavage and by digestion with Staphylococcus V8 protease. A continuous sequence of 80 residues from the N terminus was determined: TKYSESYCDV10, LIVGAGPAGL20 MAARVLSEYV30 RQKPDLKVRI40 IDKRSTKVYN50 GQADGLQCRT60 LESLKNLRLA70 DKIXSEXNDM80. A single N-terminal sequence was detected, suggesting two identical subunits in the dimeric enzyme. We suggest the occurrence of an FAD-binding site near the N terminus. The C-terminal sequence is -LSTA, as determined by carboxypeptidase digestion.

Amino Acid Sequence↗
PubMed1990

Peptide mapping on HIV polypeptides expressed in Escherichia coli. Quality control of different batches and identification of tryptic fragments containing residues of aromatic amino acids or cysteine.

Peptide mapping was used for the quality control of different batches of the recombinant HIV proteins p24 core and p24-gp41, expressed in Escherichia coli. These proteins comprise gag and env region polypeptides of the virus and may serve as suitable components in the diagnosis of HIV infections. The proteins were digested with trypsin and the mixtures were subjected to peptide mapping to prove batch equivalence of p24-gp41 and to isolate fragments of the p24-gp41 digest that differ from those of the p24 core digest. The proteins were reduced with dithiothreitol and the cysteine residues were derivatized by addition of 4-vinylpyridine. Peptide mapping was performed by means of reversed-phase high-performance liquid chromatography. Batch equivalence was proved by comparison of the maps. Peaks present in one map but not in the other were considered to be due to sequence differences or variability in digestion.

Amino Acid Sequence↗
PubMed1990

Amino acid sequence from degu islet amyloid-derived insulin shows unique sequence characteristics.

The main protein of enriched and purified amyloid from Octodon degus pancreatic islets was identified as insulin. The material was reduced and alkylated and the A- and the B-chain were separated by reversed phase chromatography and subjected to Edman degradation and amino acid analysis. It was shown that the A-chain contains two additional C-terminal amino acid residues (i.e. a total of 23 residues) and that the B-chain has a deletion in the C-terminal part (i.e. a total of 29 residues). The obtained sequence follows: A-chain: GIVDQCCNNICTFNQLQNYCNVP B-chain: YSSQHLCGSNLVEALYMTCGRSGFYRPHD.

Amino Acid Sequence↗
PubMed1990

TGF-beta 1 binding protein: a component of the large latent complex of TGF-beta 1 with multiple repeat sequences.

TGF-beta occurs in a latent complex of high Mr. We report the cDNA cloning and an initial structural and functional characterization of a component of the large latent TGF-beta 1 complex, denoted TGF-beta 1 binding protein (TGF-beta 1-BP). Most of the sequence of fibroblast TGF-beta 1-BP is made up of cysteine-rich repeats of two different kinds; there are 16 EGF-like repeats and three repeats with a distant resemblance to EGF, but of a distinct type hitherto not found in any other protein. beta-hydroxylated asparagine residues were identified in two of the EGF-like repeats. TGF-beta 1-BP purified from human platelets is considerably smaller than the fibroblast form (125-160 kd vs. 170-190 kd), suggesting that there is alternative splicing of the TGF-beta 1-BP gene or that TGF-beta 1-BP undergoes cell-specific proteolysis. TGF-beta 1-BP was found not to bind and inactive TGF-beta 1; its role in the latent complex is discussed.

Amino Acid Sequence↗
PubMed1990

Amino acid sequences around the pyridoxal-5'-phosphate-binding sites of phenol hydroxylase.

Phenol hydroxylase was labelled with pyridoxal 5'-phosphate. A radioactive label was introduced by using sodium boro[3H]hydride to reduce the initially formed Schiff's base. The labelled enzyme was digested with Staphylococcus V8 protease. Labelled peptides were isolated and their sequences were determined. The label could be located to three different lysyl residues. Sequence similarities with the known structures of p-hydroxybenzoate hydroxylase and glutathione reductase are discussed. The positions of the labelled sequences, relative to the bound ligands at the active site, are proposed on the basis of such sequence similarities.

Amino Acid Sequence↗
PubMed1990

Localization of platelet-derived endothelial cell growth factor in human placenta and purification of an alternatively processed form.

Platelet-derived endothelial cell growth factor (PD-ECGF) was purified to homogeneity from human term placenta, an organ characterized by extensive angiogenesis. N-terminal amino acid sequencing revealed that placental PD-ECGF was proteolytically processed at Thr-6, in contrast to PD-ECGF purified from human platelets, which is processed at Ala-11. The purified factor stimulated porcine aortic endothelial cells as well as two choriocarcinoma cell lines. Immunohistochemical staining revealed that PD-ECGF was present in the connective tissue cells of the placenta. The possibility that PD-ECGF is involved in the development of the placenta is discussed.

Amino Acid Sequence↗
PubMed1990

A polyclonal antiserum against chromogranin A and B--a new sensitive marker for neuroendocrine tumours.

Chromogranins A, B, and C, proteins that are co-stored and co-released with peptides and amines, have been identified in a variety of neuroendocrine tissues, both normal and neoplastic. We examined the secretion of chromogranin A and chromogranin A + B by hormone-producing tumours in patients with endocrine pancreatic tumours, carcinoid tumours, pheochromocytomas, and small cell lung cancer. The radioimmunoassay determining the plasma concentrations of chromogranin A + B showed a greater sensitivity than that determining chromogranin A alone. All patients with endocrine pancreatic tumours, carcinoids, and pheochromocytomas had increased levels of chromogranin A + B, whereas a small number of the patients (5/18 with endocrine pancreatic tumours and 1/3 with pheochromocytomas) had normal levels of chromogranin A. Also in immunocytochemical stainings, our polyclonal antiserum detecting both chromogranin A and B showed a greater sensitivity than other available antisera against chromogranin A, B and C. We have demonstrated that a polyclonal antiserum against a mixture of chromogranin A and B might be a more sensitive marker than chromogranin A alone for diagnosing neuroendocrine tumours. This is not surprising, since both chromogranins are widely distributed in neuroendocrine cells.

Amino Acids↗
PubMed1989

Further characterization and partial amino acid sequence of a cysteine proteinase from Trypanosoma cruzi.

A cysteine proteinase from epimastigotes of Trypanosoma cruzi, Tul 2 stock, has been purified to homogeneity from cell-free extracts obtained by freezing and thawing, by a procedure involving ammonium sulfate fractionation, DEAE-Sephacel chromatography, and gel filtration on Sephadex G-200; when necessary, further purification was attained by fast protein liquid chromatography on Mono Q and Superose 6 columns. The purified enzyme was strongly inhibited by leupeptin, antipain and chymostatin (I50 values of 0.25, 0.75 and 1 microM, respectively), little inhibited by elastatinal, and unaffected by pepstatin A. The enzyme is a glycoprotein, as shown by binding to ConA-Sepharose and elution with alpha-methyl-D-mannopyranoside and alpha-methyl-D-glucopyranoside. Partial amino acid sequences were obtained from the N-terminal end (32 amino acids) of the carbamidomethylated enzyme, and from a tryptic peptide (14 amino acids) of the pyridylethylated enzyme. Both regions show considerable homology with papain and some cathepsins, such as cathepsin L, thus showing that the enzyme belongs to the cysteine proteinase family.

Amino Acid Sequence↗
PubMed1989

Chromogranins--new sensitive markers for neuroendocrine tumors.

Chromogranins A, B and C, proteins that are costored and coreleased with peptides and amines, have been identified in a variety of endocrine and nervous tissues, both normal and neoplastic. We examined the secretion of chromogranin A and chromogranin A + B by hormone-producing tumors in patients with endocrine pancreatic tumors (EPT), carcinoid tumors, pheochromocytomas and small cell lung cancer (SCLC). Radioimmunoassay (RIA) of the plasma/serum concentrations of chromogranin A + B showed a greater sensitivity than RIA of chromogranin A alone. All patients with EPT, carcinoids and pheochromocytomas had increased levels of chromogranin A + B, whereas a small number of the patients (5/18 with EPT and 1/3 with pheochromocytomas) had normal levels of chromogranin A. Also in immunocytochemical stainings, our polyclonal antiserum detecting both chromogranin A and B showed a greater sensitivity than other available antisera against chromogranin A, B and C.

Adenoma, Islet Cell↗