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Pająk M, Kamysz E, Sikora K, Fichna J, Woźniczka M. Complex-Forming Properties of the Anti-Inflammatory Sialorphin Derivative Palmitic Acid-Lysine-Lysine-Glutamine-Histidine-Asparagine-Proline-Arginine with Cu(II) Ions in an Aqueous Solution. Molecules 2023; 29:90. [PMID: 38202673 PMCID: PMC10779640 DOI: 10.3390/molecules29010090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 01/12/2024] Open
Abstract
The present work describes the complexation of the anti-inflammatory sialorphin derivative Pal-Lys-Lys-Gln-His-Asn-Pro-Arg (palmitic acid-lysine-lysine-glutamine-histidine-asparagine-proline-arginine) with Cu(II) ions in an aqueous solution, at a temperature of 25.0 ± 0.1 °C, over the whole pH range. The complexing properties were characterized by potentiometric and UV-Vis spectrophotometric methods. The potentiometric method was used to calculate the logarithms of the overall stability constants (log β) and the values of the stepwise dissociation constants (pKa) of the studied complexes. The percentage of each species formed in an aqueous solution was estimated from the species distribution curve as a function of pH. The absorbance (A) and molar absorption coefficient (ε) values for the Cu(II)-sialorphin derivative system were determined with UV-Vis spectroscopy. Our studies indicate that the sialorphin derivative forms stable complexes with Cu(II) ions, which may lead to future biological and therapeutic applications.
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Affiliation(s)
- Marek Pająk
- Department of Physical and Biocoordination Chemistry, Medical University of Lodz, Muszyńskiego 1, 90-151 Lodz, Poland;
| | - Elżbieta Kamysz
- Laboratory of Chemistry of Biological Macromolecules, Department of Molecular Biotechnology, Faculty of Chemistry, University of Gdańsk, 80-308 Gdańsk, Poland;
| | - Karol Sikora
- Department of Inorganic Chemistry, Faculty of Pharmacy, Medical University of Gdańsk, Al. Gen. J. Hallera 107, 80-416 Gdańsk, Poland;
| | - Jakub Fichna
- Department of Biochemistry, Medical University of Lodz, Mazowiecka 5, 92-215 Lodz, Poland;
| | - Magdalena Woźniczka
- Department of Physical and Biocoordination Chemistry, Medical University of Lodz, Muszyńskiego 1, 90-151 Lodz, Poland;
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Peacey L, Peacey C, Gutzinger A, Jones CE. Copper(II) Binding by the Earliest Vertebrate Gonadotropin-Releasing Hormone, the Type II Isoform, Suggests an Ancient Role for the Metal. Int J Mol Sci 2020; 21:ijms21217900. [PMID: 33114333 PMCID: PMC7663483 DOI: 10.3390/ijms21217900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 10/19/2020] [Accepted: 10/22/2020] [Indexed: 02/07/2023] Open
Abstract
In vertebrate reproductive biology copper can influence peptide and protein function both in the pituitary and in the gonads. In the pituitary, copper binds to the key reproductive peptides gonadotropin-releasing hormone I (GnRH-I) and neurokinin B, to modify their structure and function, and in the male gonads, copper plays a role in testosterone production, sperm morphology and, thus, fertility. In addition to GnRH-I, most vertebrates express a second isoform, GnRH-II. GnRH-II can promote testosterone release in some species and has other non-reproductive roles. The primary sequence of GnRH-II has remained largely invariant over millennia, and it is considered the ancestral GnRH peptide in vertebrates. In this work, we use a range of spectroscopic techniques to show that, like GnRH-I, GnRH-II can bind copper. Phylogenetic analysis shows that the proposed copper-binding ligands are retained in GnRH-II peptides from all vertebrates, suggesting that copper-binding is an ancient feature of GnRH peptides.
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Peacey L, Elphick MR, Jones CE. Roles of copper in neurokinin B and gonadotropin-releasing hormone structure and function and the endocrinology of reproduction. Gen Comp Endocrinol 2020; 287:113342. [PMID: 31783025 DOI: 10.1016/j.ygcen.2019.113342] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/24/2019] [Accepted: 11/25/2019] [Indexed: 11/30/2022]
Abstract
Copper is a metal ion present in all organisms, where it has well-known roles in association with proteins and enzymes essential for cellular processes. In the early decades of the twentieth century copper was shown to influence mammalian reproductive biology, and it was subsequently shown to exert effects primarily at the level of the pituitary gland and/or hypothalamic regions of the brain. Furthermore, it has been reported that copper can interact with key neuropeptides in the hypothalamic-pituitary-gonadal axis, notably gonadotropin-releasing hormone (GnRH) and neurokinin B. Interestingly, recent phylogenetic analysis of the sequences of GnRH-related peptides indicates that copper binding is an evolutionarily ancient property of this neuropeptide family, which has been variously retained, modified or lost in the different taxa. In this mini-review the metal-binding properties of neuropeptides in the vertebrate reproductive pathway are reviewed and the evolutionary and functional significance of copper binding by GnRH-related neuropeptides in vertebrates and invertebrates are discussed.
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Affiliation(s)
- Lorraine Peacey
- School of Science and Health, The University of Western Sydney, Locked Bag 1797, Penrith, New South Wales, Australia
| | - Maurice R Elphick
- Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road, London E14NS, UK
| | - Christopher E Jones
- School of Science and Health, The University of Western Sydney, Locked Bag 1797, Penrith, New South Wales, Australia.
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Kotarba G, Zielinska-Gorska M, Biernacka K, Gajewska A. Gonadotropin-releasing hormone-Cu complex (Cu-GnRH) transcriptional activity in vivo in the female rat anterior pituitary gland. Brain Res Bull 2020; 156:67-75. [PMID: 31931118 DOI: 10.1016/j.brainresbull.2020.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 12/23/2019] [Accepted: 01/03/2020] [Indexed: 12/01/2022]
Abstract
Unlike gonadotropin-releasing hormone (GnRH) analogues characterized by amino acid replacement in decapeptide primary structure, Cu-GnRH molecule preserves the native sequence but contains a Cu2+ ion stably bound to the nitrogen atoms including that of the imidazole ring of His2. Cu-GnRH can operate via cAMP/PKA signalling in anterior pituitary cells, suggesting that it may affect selected gonadotropic network gene transcription in vivo. We analysed pituitary mRNA expression of Egr-1, Nr5a1, and Lhb based on their role in luteinizing hormone (LH) synthesis; and Nos1, Adcyap1, and Prkaca due to their dependence on cAMP/PKA activity. In two independent experiments, ovariectomized rats received intracerebroventricular pulsatile (one pulse/h or two pulses/h over 5 h) microinjections of 2 nM Cu-GnRH; 2 nM antide (GnRH antagonist) + 2 nM Cu-GnRH; 100 nM PACAP6-38 (PACAP receptor antagonist) + 2 nM Cu-GnRH. Relative expression of selected mRNAs was determined by qRT-PCR. LH serum concentration was examined according to RIA. All examined genes responded to Cu-GnRH stimulation with increased transcriptional activity in a manner dependent on pulse frequency pattern. Increased expression of Nr5a1, Lhb, Nos1, Adcyap1, and Prkaca mRNA was observed solely in rats receiving the complex with frequency of two pulses/h over 5 h. Egr-1 transcription was up-regulated for both applied Cu-GnRH pulsatile patterns. The stimulatory effect of Cu-GnRH on gene transcription was dependent on both GnRH receptor and PAC-1 activation. In conclusion, obtained results indicate that Cu-GnRH complex is a GnRH analogue able to induce both IP3/PKC and cAMP/PKA-dependent gonadotrope network gene transcription in vivo.
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Affiliation(s)
- Grzegorz Kotarba
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 3 Instytucka St., 05-110 Jablonna, Poland.
| | - Marlena Zielinska-Gorska
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 3 Instytucka St., 05-110 Jablonna, Poland.
| | - Katarzyna Biernacka
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 3 Instytucka St., 05-110 Jablonna, Poland
| | - Alina Gajewska
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 3 Instytucka St., 05-110 Jablonna, Poland.
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Stevenson MJ, Uyeda KS, Harder NHO, Heffern MC. Metal-dependent hormone function: the emerging interdisciplinary field of metalloendocrinology. Metallomics 2019; 11:85-110. [PMID: 30270362 PMCID: PMC10249669 DOI: 10.1039/c8mt00221e] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
For over 100 years, there has been an incredible amount of knowledge amassed concerning hormones in the endocrine system and their central role in human health. Hormones represent a diverse group of biomolecules that are released by glands, communicate signals to their target tissue, and are regulated by feedback loops to maintain organism health. Many disease states, such as diabetes and reproductive disorders, stem from misregulation or dysfunction of hormones. Increasing research is illuminating the intricate roles of metal ions in the endocrine system where they may act advantageously in concert with hormones or deleteriously catalyze hormone-associated disease states. As the critical role of metal ions in the endocrine system becomes more apparent, it is increasingly important to untangle the complex mechanisms underlying the connections between inorganic biochemistry and hormone function to understand and control endocrinological phenomena. This tutorial review harmonizes the interdisciplinary fields of endocrinology and inorganic chemistry in the newly-termed field of "metalloendocrinology". We describe examples linking metals to both normal and aberrant hormone function with a focus on highlighting insight to molecular mechanisms. Hormone activities related to both essential metal micronutrients, such as copper, iron, zinc, and calcium, and disruptive nonessential metals, such as lead and cadmium are discussed.
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Affiliation(s)
- Michael J Stevenson
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA.
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Gul AS, Tran KK, Jones CE. Neurokinin B and serum albumin limit copper binding to mammalian gonadotropin releasing hormone. Biochem Biophys Res Commun 2018; 497:1-6. [DOI: 10.1016/j.bbrc.2017.12.165] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 12/30/2017] [Indexed: 02/07/2023]
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The Coordination Abilities of Three Novel Analogues of Saliva Peptides: The Influence of Structural Modification on the Copper Binding. Int J Pept Res Ther 2017; 23:409-418. [PMID: 29170620 PMCID: PMC5681609 DOI: 10.1007/s10989-016-9569-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2016] [Indexed: 11/16/2022]
Abstract
Three novel analogues of salivary peptides as sialorphin (QHNPR) and opiorphin (QRFSR) were synthesized by the solid-phase method. The sequences of these ligands were following: AHNPR, QANPR and QRFPR. The aim of our work was investigation in what way some structural modifications may impact on coordination abilities of studied peptides. In this work we presented the interaction of pentapeptides with copper(II) ions in wide range of pH. To determine the coordination model of ligands there were carried out several studies by spectroscopy (UV–Vis, CD) methods and potentiometric measurements.
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Walencik PK, Stokowa-Sołtys K, Wieczorek R, Komarnicka UK, Kyzioł A, Jeżowska-Bojczuk M. Impact of the Cu(II) ions on the chemical and biological properties of goserelin – coordination pattern, DNA degradation, oxidative reactivity and in vitro cytotoxicity. J Inorg Biochem 2017; 175:167-178. [DOI: 10.1016/j.jinorgbio.2017.07.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/12/2017] [Accepted: 07/16/2017] [Indexed: 10/19/2022]
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9
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Kamysz E, Kotynia A, Czyżnikowska Ż, Jaremko M, Jaremko Ł, Nowakowski M, Brasun J. Sialorphin and its analog as ligands for copper(II) ions. Polyhedron 2013. [DOI: 10.1016/j.poly.2012.10.055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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10
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Won HS. NMR Studies of Metal-binding Luteinizing Hormone Releasing Hormone. B KOREAN CHEM SOC 2011. [DOI: 10.5012/bkcs.2011.32.11.4021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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11
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Kozłowski H, Kowalik-Jankowska T, Jeżowska-Bojczuk M. Chemical and biological aspects of Cu2+ interactions with peptides and aminoglycosides. Coord Chem Rev 2005. [DOI: 10.1016/j.ccr.2005.04.027] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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12
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D'Amelio N, Gaggelli E, Gajewska A, Kochman H, Kochman K, Kozlowski H, Latajka Z, Mlynarz P, Panek J, Valensin G. Structural analysis and sheep pituitary receptor binding of GnRH and its complexes with metal ions. J Inorg Biochem 2003; 94:28-35. [PMID: 12620670 DOI: 10.1016/s0162-0134(02)00630-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Binding of GnRH and its metal complexes to a sheep pituitary receptor have been investigated showing that Cu(II)-GnRH complex is more effectively bound to the receptor than the metal-free ligand, while Ni(II) and Co(II) complexes are less effective than the metal-free GnRH. Earlier studies have explained reasonably well the complex formation with cupric ion, while in this work extensive 1H NMR measurements have been performed for free gonadotropin-releasing hormone (GnRH) and its complexes with Ni(II) in DMSO (dimethyl sulfoxide) solution. This study shows the high order of organization of the metal-free peptide in DMSO solution with two structured 'domains' whose relative orientation is modulated by the mobility of the central glycine. Furthermore, theoretical calculations were performed for the Ni(II)-GnRH complex. The data obtained in this work supports previous studies on the co-ordination of Ni(II) ions with GnRH in aqueous solutions at high pH [J. Inorg. Biochem. 33 (1988) 11] and suggest an experimental procedure to reproduce high pH in DMSO solution. In the Ni(II) complex, the metal ion was found to co-ordinate with four nitrogen atoms inducing a well definite arrangement of aromatic side-chains and a rigid backbone structure.
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Affiliation(s)
- Nicola D'Amelio
- Dipartimento di Chimica e Centro NMR, Università di Siena, Via Aldo Moro, 53100, Siena, Italy
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Ananthanarayanan VS, Brimble KS. Interaction of oxytocin with Ca2+: I. CD and fluorescence spectral characterization and comparison with vasopressin. Biopolymers 2000; 40:433-43. [PMID: 9062067 DOI: 10.1002/(sici)1097-0282(1996)40:5%3c433::aid-bip2%3e3.0.co;2-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Extracellular Ca2+ is required for the action of oxytocin and both the hormone and its receptor have binding sites for divalent metal cations. To characterize the cation-bound form of oxytocin, we monitored the binding of Ca2+ and Mg2+ to oxytocin as well as peptides representing its ring and tail regions in trifluoroethanol, a lipid-mimetic solvent, using CD and fluorescence spectroscopy. Binding Ca2+ (Kd approximately 50 microM) caused drastic CD and fluorescence changes leading to a helical conformation. Mg2+ caused CD changes smaller than and opposite to Ca2+. However, the helical structure was enhanced when both Ca2+ and Mg2+ were present together. CD changes in the tail peptide of oxytocin showed its ability to bind Ca2+ and Mg2+ whereas the vasopressin tail peptide did not bind either cation. CD spectral changes on Ca2+ and Mg2+ binding to tocinoic acid (the ring moiety of oxytocin) were much smaller than those of oxytocin. These data suggest that the tail segment of oxytocin potentiates Ca2+ binding by the ring. While vasopressin displayed a CD spectrum similar to that of oxytocin, CD spectra of its cation-bound forms were markedly different from those of oxytocin; the Ca(2+)-induced CD changes in vasopressin were very much smaller and of opposite sign, and Mg(2+)-induced ones significantly larger than in oxytocin. Taken together, our observations bring out the structural differences between oxytocin and vasopressin in the context of their interaction with Ca2+ and Mg2+. This may be relevant to understanding the differences in the bioactive conformations and receptor interactions of the two hormones.
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Ananthanarayanan VS, Salehian O, Brimble KS. Interaction of gonadotropin-releasing hormone and its agonist analogs with Ca2+ in a nonpolar milieu. Correlation with biopotencies. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 1998; 52:185-94. [PMID: 9774231 DOI: 10.1111/j.1399-3011.1998.tb01475.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Extracellular Ca2+ is necessary for the action of gonadotropin-releasing hormone (GnRH). Assuming that this partly because of the interaction of the hormone with the relatively abundant extracellular Ca2+ in the low dielectric milieu of the bilayer plasma membrane, we studied the interaction of GnRH and five of its agonist analogs with Ca2+ under membrane-mimetic conditions. The peptides used, in increasing order of their reported gonadotropin-releasing activities, were: des-amide GnRH (or GnRH-OH); [Ala6]GnRH; [D-Ala6]GnRH; des-Gly10[D-Ala6,Pro9-NHEt]GnRH and, des-Gly10[D-Trp6,Pro9-NHEt]GnRH. Changes in the far-UV CD and fluorescence spectra of these peptides in trifluoroethanol were used to monitor conformational changes and obtain the Ca2+-binding isotherms. The data show that GnRH and its active analogs contain two Ca2+ binding sites, whereas the inactive analogs have only one. The extent of Ca2+ binding by the agonist peptides paralleled their biological potency ranking. The superactive analog des-Gly10[D-Trp6,Pro9-NHEt]GnRH exhibited the ability to transport Ca2+ ions across large unilamellar vesicles of dimyristoylphosphatidylcholine. Our study shows that significant differences among the GnRH and its analog peptides, suggestive of differences in their conformations, are manifested only in the presence of Ca2+. This observation would provide a basis for understanding GnRH action in terms of the hormone's interaction with Ca2+ in the lipid milieu.
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Jefferson EA, Gantzel P, Benedetti E, Goodman M. A Multinuclear Ca2+ Complex of a Linear N-Protected Glycyl-Dipeptoid Derivative. J Am Chem Soc 1997. [DOI: 10.1021/ja970033n] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Elizabeth A. Jefferson
- Department of Chemistry & Biochemistry University of California, San Diego La Jolla, California 92093-0343 Biocrystallography Research Centre Dipartimento di Chimica Universita' di Napoli “Federico II” Via Mezzocannone 4, 80134 Napoli, Italy
| | - Peter Gantzel
- Department of Chemistry & Biochemistry University of California, San Diego La Jolla, California 92093-0343 Biocrystallography Research Centre Dipartimento di Chimica Universita' di Napoli “Federico II” Via Mezzocannone 4, 80134 Napoli, Italy
| | - Ettore Benedetti
- Department of Chemistry & Biochemistry University of California, San Diego La Jolla, California 92093-0343 Biocrystallography Research Centre Dipartimento di Chimica Universita' di Napoli “Federico II” Via Mezzocannone 4, 80134 Napoli, Italy
| | - Murray Goodman
- Department of Chemistry & Biochemistry University of California, San Diego La Jolla, California 92093-0343 Biocrystallography Research Centre Dipartimento di Chimica Universita' di Napoli “Federico II” Via Mezzocannone 4, 80134 Napoli, Italy
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Daniele PG, Prenesti E, Ostacoli G. Ultraviolet–circular dichroism spectra for structural analysis of copper(II) complexes with aliphatic and aromatic ligands in aqueous solution. ACTA ACUST UNITED AC 1996. [DOI: 10.1039/dt9960003269] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Ananthanarayanan VS, Brimble KS. Interaction of oxytocin with Ca2+: I. CD and fluorescence spectral characterization and comparison with vasopressin. Biopolymers 1996. [DOI: 10.1002/(sici)1097-0282(1996)40:5<433::aid-bip2>3.0.co;2-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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18
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Kowalik-Jankowska T, Onindo CO, Kozlowski H, Pettit LD, Lankiewicz L, Jasionowski M. Specific binding of Cu(II) ions by leucine-enkephalin analogs. J Inorg Biochem 1995; 60:21-9. [PMID: 7595469 DOI: 10.1016/0162-0134(94)00084-n] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Results are reported from a potentiometric and spectroscopic (UV-visible, CD, and ESR) of the protonation constants and Cu(II)-complex stability constants of leucine enkephalin amide (H-Tyr-Gly-Gly-Phe-Leu-NH2, Leu-EN-amide) and two nitro analogs having 4-nitro substituent on the phenyl ring of the Phe residue, (H-Tyr-Gly-Gly-Phe(NO2)-LeuNH2, Leu-EN(nitro)- amide) and the other one with a sarcosine residue replacing the Gly3 residue (Leu-ENSar-amide). Over the pH range of 6-8.5, Leu-EN-amide interacts more strongly with Cu(II) than does the methionine analog, forming a more stable complex with three nitrogens coordinated. The Sar residue acts as a "breakpoint" to the formation of 3N or 4N complexes and, as a result, causes the formation of dimeric complexes bonded through the amino-N, a deprotonated peptide-N- and deprotonated Tyr-O- donors.
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Bal W, Kozlowski H, Robbins R, Pettit LD. Competition between the terminal amino and imidazole nitrogen donors for coordination to Ni(II) ions in oligopeptides. Inorganica Chim Acta 1995. [DOI: 10.1016/0020-1693(94)04333-q] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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20
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Bal W, Kozlowski H, Lisowski M, Pettit L, Robbins R, Safavi A. A dramatic change in the interaction of Cu(II) with bio-peptides promoted by SDS--a model for complex formation on a membrane surface. J Inorg Biochem 1994; 55:41-52. [PMID: 7519253 DOI: 10.1016/0162-0134(94)85131-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The extent of complex formation between Cu(II) and many biologically active oligopeptides has been shown to change significantly in the presence of SDS micelles, a recognized model for cell lipid membranes. Protonation constants of peptides can be increased by up to 2 log unit, especially when they contain hydrophobic side chains. Metal complex formation is generally less extensive and the conformations of peptides can be altered dramatically when compared to those in simple aqueous solution.
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Affiliation(s)
- W Bal
- Institute of Chemistry, University of Wroclaw, Poland
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21
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Kozlowski H, Masiukiewicz E, Potargowicz E, Rzeszotarska B, Walczewska-Sumorok A. Ovulation-inducing activity of luliberin (LHRH) complexed by copper(II), nickel(II), and zinc(II) ions. J Inorg Biochem 1990; 40:121-5. [PMID: 2092076 DOI: 10.1016/0162-0134(90)80045-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We have shown that the complexation of luteinizing hormone releasing hormone, luliberin (LHRH), a hypothalamic neurohormone, by Cu(II), Ni(II), and Zn(II) may affect its basic, ovulation-inducing potency in the dose responsive manner. Some explanation of the obtained results are offered here.
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Affiliation(s)
- H Kozlowski
- Institute of Chemistry, University of Wroclaw, Poland
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Abstract
Luteinizing hormone-releasing hormone (LHRH), a hypothalamic neurohormone, forms a complex with Zn ions in solution. In order to explain the structure of this complex, the stability constants of Zn(II) complexes of LHRH and also pyroglutamyl-histidine-methylester, N-acetyl-histamine, and N-acetyl-histidine were established with the use of potentiometric technique. The nuclear magnetic resonance spectroscopy shows that the mode of coordination of Zn(II) to LHRH consists of binding to the imidazole nitrogen and the peptide oxygen of the His-Trp bond.
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Affiliation(s)
- W Bal
- Institute of Chemistry, University of Wroclaw, Poland
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