Dekan Z.,University of Queensland |
Mobli M.,University of Queensland |
Pennington M.W.,Peptides International Inc. |
Fung E.,University of California at Los Angeles |
And 2 more authors.
Angewandte Chemie - International Edition | Year: 2014
A safety-catch cysteine protecting group, S-4,4′- dimethylsulfinylbenzhydryl (Msbh), was designed and developed to expand the capabilities of synthetic strategies for the regioselective formation of disulfide bonds in cysteine-rich peptides. The directed regioselective synthesis of human hepcidin, which contains four disulfide bonds, was undertaken and led to a high-resolution NMR structure under more physiologically relevant conditions than previously. Conversely, hepcidin synthesized with the formerly assigned vicinal disulfide-bond connectivity displayed significant conformational heterogeneity under similar conditions. The two synthetic forms of human hepcidin induced ferroportin internalization with apparent EC 50 values of 2.0 (native fold, 1) and 4.4 nM (non-native fold, 2), with 2 undergoing isomerization to 1 in the presence of ferroportin expressing cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source
Sirotkin A.V.,Constantine the Philosopher University |
Pavlova S.,Constantine the Philosopher University |
Tena-Sempere M.,University of Cordoba, Spain |
Grossmann R.,Institute of Animal Genetics |
And 3 more authors.
Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology | Year: 2013
The purpose of the present study was to identify the role of age, nutritional state and some metabolic hormones in control of avian hypothalamic and ovarian ghrelin/ghrelin receptor system. We examined the effect of food restriction, administration of ghrelin 1-18, ghrelin antagonistic analogue (D-Lys-3)-GHRP-6, obestatin and combinations of them on the expression of ghrelin and ghrelin receptor (GHS-R1a) in hypothalamus and ovary of old (23. months of age) and young (7. months of age) chickens. Expression of mRNAs for ghrelin and GHS-R1a in both hypothalamus and largest ovarian follicle was measured by RT-PCR. It was observed that food restriction could promote the expression of ghrelin and GHS-R1a in hypothalamus and ovary of the old chickens, but in the young chickens it reduced expression of ghrelin and did not affect expression of GHS-R1a in the ovary. Administration of ghrelin 1-18 did not affect hypothalamic or ovarian ghrelin mRNA, but significantly increased the expression of GHS-R1a in hypothalamus, but not in ovary. (D-Lys-3)-GHRP-6, significantly stimulated accumulation of ghrelin, but not GHS-R1a mRNA in hypothalamus or ghrelin or GHS-R1a in the ovary. Ghrelin 1-18 and (D-Lys-3)-GHRP-6, when given together, were able either to prevent or to induce effect of these hormones. Obestatin administration increased expression of ghrelin gene in the hypothalamus, but not expression of hypothalamic GHS-R1a, ovarian ghrelin and GHS-R1a. Furthermore, obestatin was able to modify effect of both ghrelin and fasting on hypothalamic and ovarian mRNA for ghrelin GHS-R1a. Our results (1) confirm the existence of ghrelin and its functional receptors GHS-R1a in the chicken hypothalamus and ovary (2) confirm the age-dependent control of ovarian ghrelin by feeding, (3) demonstrate, that nutritional status can influence the expression of both ghrelin and GHS-R1a in hypothalamus and in the ovary (3) demonstrates for the first time, that ghrelin can promote generation of its functional receptor in the hypothalamus, but not in the ovary, (4) show that ghrelin1-18 and (D-Lys-3)-GHRP-6 could not only be antagonists in the action on chicken hypothalamus and ovaries, but also independent regulators and even agonists, and (5) provide first evidence for action of obestatin on hypothalamic ghrelin and on the response of hypothalamic and ovarian ghrelin/GHS-R1a system to food restriction. These data indicate the involvement of both hypothalamic and ovarian ghrelin/GHS-R1 systems in mediating the effects of nutritional status, ghrelin and obestatin on reproductive processes. © 2012 Elsevier Inc. Source
Peptides International Inc. | Date: 2009-06-23
Peptides International Inc. | Date: 2009-06-23
Biomedical compounds, namely, peptide substrates used in analyzing and detecting certain toxins for laboratory or research use; Testing kits containing peptide substrates used in analyzing and detecting certain toxins for laboratory or research use.
Czerwinski A.,Peptides International Inc. |
Valenzuela F.,Peptides International Inc. |
Afonine P.,Lawrence Berkeley National Laboratory |
Dauter M.,SAIC |
Dauter Z.,Argonne National Laboratory
Acta Crystallographica Section C: Crystal Structure Communications | Year: 2010
The title compound, C23H26F2N 2O4, is a dipeptidic inhibitor of γ-secretase, one of the enzymes involved in Alzheimer's disease. The mol-ecule adopts a compact conformation, without intra-molecular hydrogen bonds. In the crystal structure, one of the amide N atoms forms the only inter-molecular N - H⋯O hydrogen bond; the second amide N atom does not form hydrogen bonds. High-resolution synchrotron diffraction data permitted the unequivocal location and refinement without restraints of all H atoms, and the identification of the characteristic shift of the amide H atom engaged in the hydrogen bond from its ideal position, resulting in a more linear hydrogen bond. Significant residual densities for bonding electrons were revealed after the usual SHELXL refinement, and modeling of these features as additional inter-atomic scatterers (IAS) using the program PHENIX led to a significant decrease in the R factor from 0.0411 to 0.0325 and diminished the r.m.s. deviation level of noise in the final difference Fourier map from 0.063 to 0.037 e Å-3. © 2010 International Union of Crystallography. Source