Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the interaction properties of synthetic antisense (AS) peptides encoded in the antisense strand of DNA corresponding to the N-terminal 20-residue sequence of the biosynthetic precursor of Arg8-vasopressin (AVP) and its binding protein bovine neurophysin II (BNPII). Binding affinities of sense polypeptides AVP and BNPII with AS peptides were measured by analytical affinity chromatography, in each case by the extent of chromatographic retardation of a soluble polypeptide interactor on an affinity matrix containing the other interactor as the immobilized species. Chromatographically calculated dissociation constants ranged from 10(-3) to 10(-6) M. Experiments were carried out to define the selectivity and underlying forces involved in the AS peptide interactions. For AS peptide elutions on sense peptide affinity supports, reduced binding affinity with increasing 1-propanol concentration and ionic strength suggested the presence of both ionic and hydrophobic contributions to AS peptide/immobilized sense peptide recognition. This same conclusion was reached with the antisense peptides as the immobilized species and measurement of elution of sequence-simplified, truncated, and charge-depleted forms of sense peptides. Immobilized AS 20-mer affinity matrix differentially retarded AVP versus oxytocin (OT) and BNPII versus BNPI (the neurophysin related biosynthetically to OT) and was used to separate these polypeptides from acid extracts of bovine posterior pituitaries. In addition, immobilized AS 12-mer corresponding to AVP-Gly-Lys-Arg could be used to separate AVP from OT. The results confirm that antisense peptides recognize sense peptides with significant selectivity in the AVP/BNPII precursor case.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Recognition properties of antisense peptides to Arg8-vasopressin/bovine neurophysin II biosynthetic precursor sequences. 260 22

The structural organization of neurohypophysial hormone biosynthetic precursors and the interdependence between intramolecular folding and precursor self-association were examined using sequence-engineered mutants of the semisynthetic oxytocin/bovine neurophysin precursor (pros-OT/BNPI). In [N alpha 1-Ac,N epsilon 30,71-diacetimidyl, Ala2,des-His106] Pro-Ot/BNPI or [N alpha 1-Ac,Ala2]pros-OT/BNPI), two structural elements (Tyr2 and free alpha-amino group) were eliminated which were predicted to be critical for intramolecular conformation by stabilizing contact between hormone and neurophysin domains. This mutant was used to test the dependence of precursor self-association on intramolecular conformation. In the second mutant precursor, [N alpha 30,71-diacetimidyl,D-Pro7,D-Leu8,des-His106]p ro-OT/BNPI (or [D-Pro7,D-Leu8]pros-OT/BNPI), the stereochemistry at L-Pro7-L-Leu8 was changed to test the extent to which precursor conformation depends on ordered structure in the processing/spacer sequence which connects the interacting hormone and neurophysin I domains. Intramolecular conformation was characterized for the precursor and mutants by analytical affinity chromatography on immobilized hormone analog Met-Tyr-Phe and by circular dichroism. Data obtained by both methods showed that, while pros-OT/BNPI is folded, with hormone domain occupying the hormone-binding site of the neurophysin domain, the alpha-acetyl-Ala2 mutant is not so organized intramolecularly. When pros-OT/BNPI and the alpha-acetyl-Ala2 mutant were eluted on immobilized BNPII to measure self-association propensity, the native-like precursor was found to bind with 12-15-fold higher affinity than the assembly mutant. Thus, while pros-OT/BNPI assumes a molecular structure containing a high-affinity self-association surface induced by intramolecular hormone domain-neurophysin domain interaction, [N alpha 1-Ac,Ala2]pros-OT/BNPI does not. The results with the alpha-acetyl-Ala2 mutant show that intramolecular domain-domain interaction is the obligatory "trigger" which induces the high-affinity precursor self-association that likely drives precursor to aggregated forms in the concentrated intragranular environment that exists in peptide hormone-synthesizing cells. In contrast, affinity chromatographic and circular dichroism properties of the D-Pro7,D-Leu8 mutant show that this intramolecular trigger is dependent, but only weakly, on the conformation of the peptide sequence between domains, as judged by native-like interaction properties below 40 degrees C but lowered stability to elevated temperature.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Sequence redesign and the assembly mechanism of the oxytocin/bovine neurophysin I biosynthetic precursor. 365 97

An oxytocin/bovine neurophysin I biosynthetic precursor, [N epsilon-diacetimidyl-30,71, des-His106]pro-OT/BNPI, was synthesized from a synthetic oxytocinyl peptide, 1/2Cys-Tyr-Ile-Gln-Asn-1/2Cys-Pro-Leu-Gly-Gly-Lys-Arg, and native neurophysin by chemical semisynthesis. The semisynthetic precursor contains the entire sequence of the biosynthetic precursor deduced from the complementary DNA structure except for omission of the carboxyl-terminal histidine residue. The covalent structure of the semisynthetic product was verified by amino acid analysis and amino-terminal analysis. Analytical affinity chromatography was employed to evaluate noncovalent binding properties of the precursor. The precursor does not bind significantly to immobilized Met-Tyr-Phe, a hormone binding site ligand. In contrast, the acetimidated precursor binds to immobilized bovine neurophysin II, with a 13-fold higher affinity than does acetimidated neurophysin itself. When a hormonal ligand, [Lys8]vasopressin, was added to the elution buffer at the concentration of 0.1 mM so that a major portion of the immobilized BNPII was liganded, the affinity between the immobilized liganded BNPII and the precursor was enhanced 8-fold and approached the affinity for the liganded (bovine neurophysin I-immobilized BNPII) interaction. The data imply that the precursor can self-associate and that this self-association is closely related to that of liganded neurophysin. The tripeptide affinity matrix data argue that, in the precursor, the ligand binding site of the neurophysin domain is occupied intramolecularly by the hormone domain. The data verify the view that both the self-association surface and hormone binding site are established upon precursor folding. A disulfide stability analysis showed the resistance, to disulfide interchange by dithiothreitol, of semisynthetic precursor but not of neurophysin, as judged by protein association and peptide ligand binding activities, respectively. The results argue that the molecular structure of the precursor is established upon precursor folding and before enzymatic processing that produces mature hormone and neurophysin.
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PMID:Molecular properties of the oxytocin/bovine neurophysin biosynthetic precursor. Studies using a semisynthetic precursor. 400 99

Recent advances in gene technology have helped to identify novel proteins and allowed study of their distribution and functions in the mammalian brain. One class of these proteins is that of transporters, which exist in plasma and organellar membranes of neurons and other cells to move substances selectively across membranes. These transporters can be categorized further into subclasses by their structural property, substrate selectivity, and site of action. Some of them have been identified in the hypothalamus, which is the only brain site where a neural signal is converted to a humoral one, namely, a hormone for a target organ. This unique neural mechanism has long attracted attention as the neuroendocrine system, part of which has been extensively studied as the hypothalamic-neurohypophysial system involved in secretion of vasopressin and oxytocin. However, transporters in this system have been less well studied. A morphological examination of novel transporters would give us cues to a better understanding of the neuronal organization and function of the system. In this review, we first summarize recent findings on expression of transporter gene and immunoreactivity in the hypothalamus. In the second part, we explain our observations on two vesicular glutamate (inorganic phosphate) transporters (BNPI and DNPI) in the supraoptic and paraventricular nuclei and neurohypophysis. Further study of these and other transporters will provide a basis on which to reevaluate the organization and function of the hypothalamic-neurohypophysial system.
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PMID:Transporters in the neurohypophysial neuroendocrine system, with special reference to vesicular glutamate transporters (BNPI and DNPI): a review. 1181 Jul 15

L-glutamate, the main excitatory neurotransmitter, influences virtually all neurones of the neuroendocrine hypothalamus via synaptic mechanisms. Vesicular glutamate transporters (VGLUT1-3), which selectively accumulate L-glutamate into synaptic vesicles, provide markers with which to visualise glutamatergic neurones in histological preparations; excitatory neurones in the endocrine hypothalamus synthesise the VGLUT2 isoform. Results of recent dual-label in situ hybridisation studies indicate that glutamatergic neurones in the preoptic area and the hypothalamic paraventricular, supraoptic and periventricular nuclei include parvocellular and magnocellular neurosecretory neurones which secrete peptide neurohormones into the bloodstream to regulate endocrine functions. Neurosecretory terminals of GnRH, TRH, CRF-, somatostatin-, oxytocin- and vasopressin-secreting neurones contain VGLUT2 immunoreactivity, suggesting the co-release of glutamate with hypophysiotrophic peptides. The presence of VGLUT2 also indicates glutamate secretion from non-neuronal endocrine cells, including gonadotrophs and thyrotrophs of the anterior pituitary. Results of in vitro studies show that ionotropic glutamate receptor analogues can elicit hormone secretion at neuroendocrine/endocrine release sites. Structural constituents of the median eminence, adenohypophysis and neurohypophysis contain elements of glutamatergic transmission, including glutamate receptors and enzymes of the glutamate/glutamine cycle. The synthesis of VGLUT2 exhibits robust up-regulation in response to certain endocrine challenges, indicating that altered glutamatergic signalling may represent an important adaptive mechanism. This review article discusses the newly emerged non-synaptic role of glutamate in neuroendocrine and endocrine communication.
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PMID:Novel aspects of glutamatergic signalling in the neuroendocrine system. 1860 97