Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have constructed three different truncated versions of diphtheria toxin (a 535-amino-acid polypeptide) which correspond to the N-terminal 290, 377, and 485 amino acids of the toxin. These lengths include one, three, and all four of the putative membrane-spanning sequences of the toxin which are thought to play a role in the translocation of fragment A into cells. Each of these three genes has been modified at its 3' end to code for a C-terminal cysteine (to allow for disulfide linkage of a targeting ligand) or a gene fusion with alpha-melanocyte-stimulating hormone. We have also substituted the native diphtheria tox promoter (ptox) with the lambda pR promoter in an effort to overexpress these proteins. The truncated genes are expressed in Escherichia coli from both the tox promoter in a constitutive fashion and from the pR promoter by using the heat-inducible cI857 repressor. The clones produce proteins which react with anti-diphtheria toxin serum, which migrate at the anticipated Mr on Western blots, and which have ADP-ribosyltransferase activity. Constitutive synthesis from ptox leads to severe proteolytic degradation even in a protease-deficient strain. High-level expression from the pR promoter in the same lon htpR strain allows the full-length polypeptides to accumulate but also stops the growth of the cells. It appears that removal of as few as 50 amino acids from the C-terminus of diphtheria toxin alters its conformation, making it a target for proteases and causing overexpression lethality in the host cells.
 ...
PMID:Cloning and expression in Escherichia coli of three fragments of diphtheria toxin truncated within fragment B. 354 95

The primary structure of a precursor protein that contains beta-neo-endorphin, dynorphin and a third leucine-enkephalin sequence with a carboxyl extension has been deduced from the nucleotide sequence of cloned DNA complementary to the porcine hypothalamic mRNA encoding it. The three peptides are each bounded by Lys-Arg. This precursor protein, like adrenal preproenkephalin and the corticotropin/beta-lipotropin precursor, comprises multiple repetitive units and a cysteine-containing amino-terminal sequence preceded by a signal peptide.
 ...
PMID:Cloning and sequence analysis of cDNA for porcine beta-neo-endorphin/dynorphin precursor. 612 53

The precursor to corticotropin and beta-endorphin was synthesized in a reticulocyte cell-free system under the direction of mRNA from mouse AtT-20 pituitary tumor cells in the presence of [3H]proline, [3H]phenylalanine, [3H]leucine, [3H]valine, [3H]isoleucine or [35S]methionine. Automatic Edman degradation of the radioactive cell-free product showed the following N-terminal sequence: Pro-1, Met-2, Leu-11, Leu-12, Leu-13, Leu-15, Leu-16, Leu-17, Ile-21 and Val-23. The corticotropin-endorphin precursor was also labeled in AtT-20 cells with [3H]valine, [3H]leucine, [3H]tryptophan, [3H]serine, [35S]methionine or [35S]cysteine. Automatic Edman degradation of the radioactive intact cell form gave the following N-terminal sequence: Trp-1, Cys-2, Leu-3, Ser-5, Ser-6, Val-7, Cys-8, Leu-11, Leu-17, Leu-18 and tentatively Met-27. The sequence of the intact cell form from AtT-20 cells matches the sequence of the cell-free form of bovine pituitary precursor beginning at Trp-27, as determined by recombinant DNA technology [Nakanishi, S., Inoue, A., Kita, T., Nakamura, M., Chang, A. C. Y., Cohen, S. N., and Numa, S. (1979) Nature (Lond.) 278, 423-427]. The sequence of the mouse pituitary mRNA-directed cell-free translation product also matches the bovine precursor beginning at Pro-2. The results suggest that both the mouse and bovine precursors possess a signal sequence of 26 amino acids which is cleaved in intact cells. CNBr cleavage of [35S]cysteine-labelled intact cell precursor gave rise to an N-terminal fragment of a size compatible with the presence of a methionyl residue at or near position 27.
 ...
PMID:Evidence for a signal sequence at the N terminus of the common precursor to adrenocorticothrophin and beta-lipotropin in mouse pituitary cells. 616 72

The highly potent cyclic analogue of alpha-MSH, Ac-[Cys4,Cys10]-alpha-MSH4-13-NH2, was structurally modified in position 4. Four analogues were prepared and their biological activities in the in vitro frog and lizard skin bioassays were determined. It was shown that removing the terminal acetylamino group to give [Mpa4,Cys10]-alpha-MSH4-13-NH2 resulted in little change in the biological activity, but a change in the stereochemistry of cysteine in position 4 to give Ac-[D-Cys4,Cys10[-alpha-MSH4-a3-NH2 led to a small decrease of activity in both bioassays. Decreasing the size of the intramolecular ring by removing one methylene group to give [Maa2,Cys10]-alpha-MSH4-13-NH2, resulted in an analogue with lower activities in both assays (about 3 times in the lizard and 500 times in the frog), and increasing the size of the righ by methylene group to give Ac-[Hcy4,Cys10]-alpha-MSH4-13-NH2 led to much lower activities in the lizard system and similar effects were seen upon decreasing the ring size in the frog skin assay.
 ...
PMID:Cyclic melanotropins. Part VII: Modified ring structures--synthesis and biological activity. 633 35

An amino-terminal fragment of pro-opiomelanocortin (POMC) has been isolated from bovine intermediate pituitaries by reversed-phase high-performance liquid chromatography. Peptide mapping and amino acid analysis indicated that the primary sequence corresponds exactly to that predicted by cDNA techniques for the first 49 residues of POMC including the presence of four cysteine residues. This peptide is almost certainly generated together with the gamma-melanotropins during the biosynthetic processing of the 16K amino-terminal fragment of bovine POMC. Careful analysis of the fragments resulting from V8 protease and trypsin digestion has permitted assignment of cystine bridges between residues 2 and 24 and between residues 8 and 20.
 ...
PMID:Isolation and characterization of the 1 to 49 amino-terminal sequence of pro-opiomelanocortin from bovine posterior pituitaries. 639 86

Preliminary observations [Sykes & Lowry (1980) J. Endocrinol. 85, 42P-43P] had suggested that the major hypothalamic somatoliberin (growth-hormone-releasing factor) was a larger peptide than the other characterized hypothalamic factors, with an elution position on Sephadex G-50 between those of neurophysin and corticotropin. The present paper reports the isolation and preliminary characterization of pig hypothalamic somatoliberin. Acid extracts of pig stalk median eminence were purified by gel filtration and preparative and analytical high-pressure liquid chromatography to yield a preparation that was specific in the release of somatotropin (growth hormone) in vitro, giving a steep dose--response curve at doses in the range 0.20-3.0 ng. Amino acid analysis revealed a non-cysteine-containing peptide with a high number of glutamate (or glutamine) and aspartate (or asparagine) residues. The peptide had about 56-57 amino acid residues and an apparent molecular weight of 6400, in keeping with its elution position on a column of Sephadex G-50.
 ...
PMID:Purification of a high-molecular-weight somatoliberin (growth-hormone-releasing factor) from pig hypothalami. 640 74

The murine agouti gene encodes for a novel 131 amino acid protein. The sequence includes a 22 residue putative secretion signal, an internal basic region, and a C-terminal domain containing 10 cysteines. Agouti has been found to antagonize the binding of certain pro-opiomelanocortin peptides, such as alpha-melanocyte stimulating hormone (alpha-MSH), to the murine melanocortin-1 receptor (MC1-R). We report the purification of a secreted murine agouti to homogeneity by a two-step procedure from baculovirus-infected Trichoplusia ni (T. ni). The protein is glycosylated and exhibits competitive, high-affinity antagonism (Ki = 0.8 nM) versus alpha-MSH in cell-based assays employing B16F10 cells. Association state analysis by analytical ultracentrifugation reveals that agouti exists in a monomer--dimer plus aggregate equilibrium at low micromolar concentrations. Data from secondary structure studies indicate that the protein is highly stable to thermal denaturation. Enzymatic digestion to probe disulfide bond arrangement yielded a discrete C-terminal (Val 83-Cys 131) domain. The isolated highly cysteine-rich C-terminal domain retains alpha-MSH antagonism equipotent with mature agouti. This bioactive domain contains all 10 cysteines which exhibit sequence homology when aligned with several conotoxins.
 ...
PMID:Agouti structure and function: characterization of a potent alpha-melanocyte stimulating hormone receptor antagonist. 754 77

The NH2-terminal region of pro-opiomelanocortin (POMC) is highly conserved across species, having two disulfide bridges that cause the formation of an amphipathic hairpin loop structure between the 2nd and 3rd cysteine residues (Cys8 to Cys20). The role that the NH2-terminal region of pro-opiomelanocortin plays in acting as a molecular sorting signal for the regulated secretory pathway was investigated by using site-directed mutagenesis either to disrupt one or more of the disulfide bridges or to delete the amphipathic loop entirely. When POMC was expressed in Neuro-2a cells, ACTH immunoreactive material was localized in punctate secretory granules in the cell body and along the neurites, with heavy labeling at the tips. ACTH was secreted from these POMC-transfected cells in a regulated manner. Disruption of both disulfide bridges or the second disulfide bridge or removal of the amphipathic hairpin loop resulted in constitutive secretion of the mutant POMC from the cells and a lack of punctate secretory granule immunostaining within the cells. We have modeled the NH2-terminal POMC Cys8 to Cys20 domain and have identified it as an amphipathic loop containing four highly conserved hydrophobic and acidic amino acid residues (Asp10-Leu11-Glu14-Leu1). Thus the sorting signal for POMC to the regulated secretory pathway appears to be encoded by a specific conformational motif comprised of a 13-amino acid amphipathic loop structure stabilized by a disulfide bridge, located at the NH2 terminus of the molecule.
 ...
PMID:Identification of the sorting signal motif within pro-opiomelanocortin for the regulated secretory pathway. 772 77

A display-phage library (TN2), displaying an 18-residue peptide fused to coat protein III, represents a collection of up to 8.55 x 10(6) peptides encoded by only 1.68 x 10(7) DNA sequences. Each displayed peptide has two fixed cysteine residues (allowing disulfide formation) and six variegated residues, four between the cysteines and one either side of the cysteines. Screening this library against streptavidin (Sv) and the anti-beta-endorphin monoclonal antibody, 3-E7, yielded phage displaying disulfide-constrained microproteins with sequences similar to those published for the linear-peptide display phage. Analysis of selected clones indicated that a disulfide bond is required for high-affinity binding to each of the target proteins. The microproteins selected for binding to Sv and 3-E7 show more stringent sequence specificity than do linear peptides selected for binding to the same targets.
 ...
PMID:M13 bacteriophage displaying disulfide-constrained microproteins. 850 57

Chromogranins A and B and secretogranin II are a family of acidic proteins found in neuroendocrine secretory vesicles; these proteins contain multiple potential cleavage sites for proteolytic processing by the mammalian subtilisin-like serine endoproteases PC1 and PC2 (prohormone convertases 1 and 2), and furin. We explored the role of these endoproteases in chromogranin processing in AtT-20 mouse pituitary corticotropes. Expression of inducible antisense PC1 mRNA virtually abolished PC1 immunoreactivity on immunoblots. Chromogranin A immunoblots revealed chromogranin A processing, from both the NH2 and COOH termini, in both wild-type AtT-20 and AtT-20 antisense PC1 cells. After antisense PC1 induction, an approximately 66-kD chromogranin A NH2-terminal fragment as well as the parent chromogranin A molecule accumulated, while an approximately 50 kD NH2-terminal and an approximately 30 kD COOH-terminal fragment declined in abundance. Chromogranin B and secretogranin II immunoblots showed no change after PC1 reduction. [35S]Methionine/cysteine pulse-chase metabolic labeling in AtT-20 antisense PC1 and antisense furin cells revealed reciprocal changes in secreted chromogranin A COOH-terminal fragments (increased approximately 82 kD and decreased approximately 74 kD forms, as compared with wild-type AtT-20 cells) indicating decreased cleavage, while AtT-20 cells overexpressing PC2 showed increased processing to and secretion of approximately 71 and approximately 27 kD NH2-terminal chromogranin A fragments. Antisense PC1 specifically abolished regulated secretion of both chromogranin A and beta-endorphin in response to the usual secretagogue, corticotropin-releasing hormone. Moreover, immunocytochemistry demonstrated a relative decrease of chromogranin A in processes (where regulated secretory vesicles accumulate) of AtT-20 cells overexpressing either PC1 or PC2. These results demonstrate that chromogranin A is a substrate for the endogenous endoproteases PC1 and furin in vivo, and that such processing influences its trafficking into the regulated secretory pathway; furthermore, lack of change in chromogranin B and secretogranin II cleavage after diminution of PCl suggests that the action of PC1 on chromogranin A may be specific within the chromogranin/secretogranin protein family.
 ...
PMID:Chromogranin A processing and secretion: specific role of endogenous and exogenous prohormone convertases in the regulated secretory pathway. 869 Jul 87


<< Previous 1 2 3 4 5 Next >>