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López L, Martínez LM, Caicedo JR, Fernández-Vega L, Cunci L. Measurement of Neuropeptide Y in Aptamer-Modified Planar Electrodes. Electrochim Acta 2024; 488:144243. [PMID: 38654828 PMCID: PMC11034791 DOI: 10.1016/j.electacta.2024.144243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Electrochemical impedance spectroscopy (EIS) is a powerful technique for studying the interaction at electrode/solution interfaces. The adoption of EIS for obtaining analytical signals in biosensors based on aptamers is gaining popularity because of its advantageous characteristics for molecular recognition. Neuropeptide Y (NPY), the most abundant neuropeptide in the body, plays a crucial role with its stress-relieving properties. Quantitative measurement of NPY is imperative for understanding its role in these and other biological processes. Although aptamer-modified electrodes for NPY detection using EIS present a promising alternative, the correlation between the data obtained and the adsorption process on the electrodes is not fully understood. Various studies utilize the change in charge transfer resistance when employing an active redox label. In contrast, label-free measurement relies on changes in capacitance. To address these challenges, we focused on the interaction between aptamer-modified planar electrodes and their target, NPY. We proposed utilizing -ω*Zimag as the analytical signal, which facilitated the analysis of the adsorption process using an analogous Langmuir isotherm equation. This approach differs from implantable microelectrodes, which adhere to the Freundlich adsorption isotherm. Notably, our method obviates the need for a redox label and enables the detection of NPY at concentrations as low as 20 pg/mL. This methodology demonstrated exceptional selectivity, exhibiting a signal difference of over 20-to-1 against potential interfering molecules.
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Affiliation(s)
- Luis López
- Department of Chemistry, University of Puerto Rico – Rio Piedras, 17 Ave Universidad Ste 1701, San Juan, Puerto Rico 00931, United States
| | - Lyza M. Martínez
- Department of Chemistry, Universidad Ana G. Méndez – Gurabo, Carr. 189, Km 3.3, Gurabo, Puerto Rico 00778, United States
| | - Jaileen R. Caicedo
- Department of Chemistry, University of Puerto Rico – Rio Piedras, 17 Ave Universidad Ste 1701, San Juan, Puerto Rico 00931, United States
| | - Lauren Fernández-Vega
- Department of Chemistry, Universidad Ana G. Méndez – Gurabo, Carr. 189, Km 3.3, Gurabo, Puerto Rico 00778, United States
- Department of Chemistry, Universidad Ana G. Méndez – Cupey, 1399 Ave Ana G Mendez, Cupey, Puerto Rico 00925, United States
| | - Lisandro Cunci
- Department of Chemistry, University of Puerto Rico – Rio Piedras, 17 Ave Universidad Ste 1701, San Juan, Puerto Rico 00931, United States
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2
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Greene ES, Abdelli N, Dridi JS, Dridi S. Avian Neuropeptide Y: Beyond Feed Intake Regulation. Vet Sci 2022; 9:171. [PMID: 35448669 PMCID: PMC9028514 DOI: 10.3390/vetsci9040171] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 11/16/2022] Open
Abstract
Neuropeptide Y (NPY) is one of the most abundant and ubiquitously expressed neuropeptides in both the central and peripheral nervous systems, and its regulatory effects on feed intake and appetite- have been extensively studied in a wide variety of animals, including mammalian and non-mammalian species. Indeed, NPY has been shown to be involved in the regulation of feed intake and energy homeostasis by exerting stimulatory effects on appetite and feeding behavior in several species including chickens, rabbits, rats and mouse. More recent studies have shown that this neuropeptide and its receptors are expressed in various peripheral tissues, including the thyroid, heart, spleen, adrenal glands, white adipose tissue, muscle and bone. Although well researched centrally, studies investigating the distribution and function of peripherally expressed NPY in avian (non-mammalian vertebrates) species are very limited. Thus, peripherally expressed NPY merits more consideration and further in-depth exploration to fully elucidate its functions, especially in non-mammalian species. The aim of the current review is to provide an integrated synopsis of both centrally and peripherally expressed NPY, with a special focus on the distribution and function of the latter.
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Affiliation(s)
- Elizabeth S. Greene
- Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA; (E.S.G.); (N.A.)
| | - Nedra Abdelli
- Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA; (E.S.G.); (N.A.)
- Animal Nutrition and Welfare Service, Department of Animal and Food Sciences, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Jalila S. Dridi
- École Universitaire de Kinésithérapie, Université d’Orléans, Rue de Chartres, 45100 Orleans, France;
| | - Sami Dridi
- Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA; (E.S.G.); (N.A.)
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3
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Vu O, Bender BJ, Pankewitz L, Huster D, Beck-Sickinger AG, Meiler J. The Structural Basis of Peptide Binding at Class A G Protein-Coupled Receptors. Molecules 2021; 27:molecules27010210. [PMID: 35011444 PMCID: PMC8746363 DOI: 10.3390/molecules27010210] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 12/15/2021] [Accepted: 12/18/2021] [Indexed: 11/16/2022] Open
Abstract
G protein-coupled receptors (GPCRs) represent the largest membrane protein family and a significant target class for therapeutics. Receptors from GPCRs’ largest class, class A, influence virtually every aspect of human physiology. About 45% of the members of this family endogenously bind flexible peptides or peptides segments within larger protein ligands. While many of these peptides have been structurally characterized in their solution state, the few studies of peptides in their receptor-bound state suggest that these peptides interact with a shared set of residues and undergo significant conformational changes. For the purpose of understanding binding dynamics and the development of peptidomimetic drug compounds, further studies should investigate the peptide ligands that are complexed to their cognate receptor.
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Affiliation(s)
- Oanh Vu
- Deparment of Chemistry, Vanderbilt University, Nashville, TN 37235, USA;
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; (B.J.B.); (L.P.)
| | - Brian Joseph Bender
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; (B.J.B.); (L.P.)
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
| | - Lisa Pankewitz
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; (B.J.B.); (L.P.)
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, Medical Department, Leipzig University, Härtelstr. 16–18, D-04107 Leipzig, Germany;
| | - Annette G. Beck-Sickinger
- Faculty of Life Sciences, Institute of Biochemistry, Leipzig University, Brüderstr. 34, D-04103 Leipzig, Germany;
| | - Jens Meiler
- Deparment of Chemistry, Vanderbilt University, Nashville, TN 37235, USA;
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; (B.J.B.); (L.P.)
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
- Leipzig University Medical Center, Institute for Drug Discovery, Departments of Chemistry and Computer Science, Leipzig University, Brüderstr. 34, D-04103 Leipzig, Germany
- Correspondence:
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4
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Cattaneo S, Verlengia G, Marino P, Simonato M, Bettegazzi B. NPY and Gene Therapy for Epilepsy: How, When,... and Y. Front Mol Neurosci 2021; 13:608001. [PMID: 33551745 PMCID: PMC7862707 DOI: 10.3389/fnmol.2020.608001] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 12/21/2020] [Indexed: 12/18/2022] Open
Abstract
Neuropeptide Y (NPY) is a neuropeptide abundantly expressed in the mammalian central and peripheral nervous system. NPY is a pleiotropic molecule, which influences cell proliferation, cardiovascular and metabolic function, pain and neuronal excitability. In the central nervous system, NPY acts as a neuromodulator, affecting pathways that range from cellular (excitability, neurogenesis) to circuit level (food intake, stress response, pain perception). NPY has a broad repertoire of receptor subtypes, each activating specific signaling pathways in different tissues and cellular sub-regions. In the context of epilepsy, NPY is thought to act as an endogenous anticonvulsant that performs its action through Y2 and Y5 receptors. In fact, its overexpression in the brain with the aid of viral vectors can suppress seizures in animal models of epilepsy. Therefore, NPY-based gene therapy may represent a novel approach for the treatment of epilepsy patients, particularly for pharmaco-resistant and genetic forms of the disease. Nonetheless, considering all the aforementioned aspects of NPY signaling, the study of possible NPY applications as a therapeutic molecule is not devoid of critical aspects. The present review will summarize data related to NPY biology, focusing on its anti-epileptic effects, with a critical appraisal of key elements that could be exploited to improve the already existing NPY-based gene therapy approaches for epilepsy.
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Affiliation(s)
- Stefano Cattaneo
- Vita-Salute San Raffaele University, Milan, Italy.,San Raffaele Scientific Institute, Milan, Italy
| | - Gianluca Verlengia
- San Raffaele Scientific Institute, Milan, Italy.,Department of Neuroscience and Rehabilitation, Section of Pharmacology, University of Ferrara, Ferrara, Italy
| | - Pietro Marino
- Department of Neuroscience and Rehabilitation, Section of Pharmacology, University of Ferrara, Ferrara, Italy.,Department of Medical Sciences, Section of Pediatrics, University of Ferrara, Ferrara, Italy
| | - Michele Simonato
- Vita-Salute San Raffaele University, Milan, Italy.,San Raffaele Scientific Institute, Milan, Italy.,Department of Neuroscience and Rehabilitation, Section of Pharmacology, University of Ferrara, Ferrara, Italy
| | - Barbara Bettegazzi
- Vita-Salute San Raffaele University, Milan, Italy.,San Raffaele Scientific Institute, Milan, Italy
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5
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Hofmann S, Bellmann-Sickert K, Beck-Sickinger AG. Chemical modification of neuropeptide Y for human Y1 receptor targeting in health and disease. Biol Chem 2019; 400:299-311. [PMID: 30653463 DOI: 10.1515/hsz-2018-0364] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 12/17/2018] [Indexed: 12/14/2022]
Abstract
As a very abundant neuropeptide in the brain and widely distributed peptide hormone in the periphery, neuropeptide Y (NPY) appears to be a multisignaling key peptide. Together with peptide YY, pancreatic polypeptide and the four human G protein-coupled receptor subtypes hY1R, hY2R, hY4R and hY5R it forms the NPY/hYR multiligand/multireceptor system, which is involved in essential physiological processes as well as in human diseases. In particular, NPY-induced hY1R signaling plays a central role in the regulation of food intake and stress response as well as in obesity, mood disorders and cancer. Thus, several hY1R-preferring NPY analogs have been developed as versatile tools to unravel the complex NPY/hY1R signaling in health and disease. Further, these peptides provide basic lead structures for the development of innovative drugs. Here, the current research is summarized focusing on the development of differently sized hY1R-preferring NPY analogs as well as their advances with respect to hY1R profiling, potential therapeutic applications and targeted cancer imaging and therapy. Finally, major limitations and innovative strategies for next generation hY1R-preferring NPY analogs are addressed.
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Affiliation(s)
- Sven Hofmann
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, D-04103 Leipzig, Germany
| | - Kathrin Bellmann-Sickert
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, D-04103 Leipzig, Germany
| | - Annette G Beck-Sickinger
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Brüderstr. 34, D-04103 Leipzig, Germany
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6
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Aresti Sanz J, El Aidy S. Microbiota and gut neuropeptides: a dual action of antimicrobial activity and neuroimmune response. Psychopharmacology (Berl) 2019; 236:1597-1609. [PMID: 30997526 PMCID: PMC6598950 DOI: 10.1007/s00213-019-05224-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 03/10/2019] [Indexed: 12/22/2022]
Abstract
The gut microbiota is comprised of a vast variety of microbes that colonize the gastrointestinal tract and exert crucial roles for the host health. These microorganisms, partially via their breakdown of dietary components, are able to modulate immune response, mood, and behavior, establishing a chemical dialogue in the microbiota-gut-brain interphase. Changes in the gut microbiota composition and functionality are associated with multiple diseases, in which altered levels of gut-associated neuropeptides are also detected. Gut neuropeptides are strong neuroimmune modulators; they mediate the communication between the gut microbiota and the host (including gut-brain axis) and have also recently been found to exert antimicrobial properties. This highlights the importance of understanding the interplay between gut neuropeptides and microbiota and their implications on host health. Here, we will discuss how gut neuropeptides help to maintain a balanced microbiota and we will point at the missing gaps that need to be further investigated in order to elucidate whether these molecules are related to neuropsychiatric disorders, which are often associated with gut dysbiosis and altered gut neuropeptide levels.
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Affiliation(s)
- Julia Aresti Sanz
- Department of Molecular Immunology and Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Sahar El Aidy
- Department of Molecular Immunology and Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands.
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7
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Kögler LM, Stichel J, Kaiser A, Beck-Sickinger AG. Cell-Free Expression and Photo-Crosslinking of the Human Neuropeptide Y 2 Receptor. Front Pharmacol 2019; 10:176. [PMID: 30881304 PMCID: PMC6405639 DOI: 10.3389/fphar.2019.00176] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 02/11/2019] [Indexed: 12/15/2022] Open
Abstract
G protein-coupled receptors (GPCRs) represent a large family of different proteins, which are involved in physiological processes throughout the entire body. Furthermore, they represent important drug targets. For rational drug design, it is important to get further insights into the binding mode of endogenous ligands as well as of therapeutic agents at the respective target receptors. However, structural investigations usually require homogenous, solubilized and functional receptors, which is still challenging. Cell-free expression methods have emerged in the last years and many different proteins are successfully expressed, including hydrophobic membrane proteins like GPCRs. In this work, an Escherichia coli based cell-free expression system was used to express the neuropeptide Y2 receptor (Y2R) for structural investigations. This GPCR was expressed in two different variants, a C-terminal enhanced green fluorescent fusion protein and a cysteine deficient variant. In order to obtain soluble receptors, the expression was performed in the presence of mild detergents, either Brij-35 or Brij-58, which led to high amounts of soluble receptor. Furthermore, the influence of temperature, pH value and additives on protein expression and solubilization was tested. For functional and structural investigations, the receptors were expressed at 37°C, pH 7.4 in the presence of 1 mM oxidized and 5 mM reduced glutathione. The expressed receptors were purified by ligand affinity chromatography and functionality of Y2R_cysteine_deficient was verified by a homogenous binding assay. Finally, photo-crosslinking studies were performed between cell-free expressed Y2R_cysteine_deficient and a neuropeptide Y (NPY) analog bearing the photoactive, unnatural amino acid p-benzoyl-phenylalanine at position 27 and biotin at position 22 for purification. After enzymatic digestion, fragments of crosslinked receptor were identified by mass spectrometry. Our findings demonstrate that, in contrast to Y1R, NPY position 27 remains flexible when bound to Y2R. These results are in agreement with the suggested binding mode of NPY at Y2R.
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Affiliation(s)
- Lisa Maria Kögler
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Leipzig, Germany
| | - Jan Stichel
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Leipzig, Germany
| | - Anette Kaiser
- Institute of Biochemistry, Faculty of Life Sciences, Leipzig University, Leipzig, Germany
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8
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Molugu TR, Lee S, Brown MF. Concepts and Methods of Solid-State NMR Spectroscopy Applied to Biomembranes. Chem Rev 2017; 117:12087-12132. [PMID: 28906107 DOI: 10.1021/acs.chemrev.6b00619] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Concepts of solid-state NMR spectroscopy and applications to fluid membranes are reviewed in this paper. Membrane lipids with 2H-labeled acyl chains or polar head groups are studied using 2H NMR to yield knowledge of their atomistic structures in relation to equilibrium properties. This review demonstrates the principles and applications of solid-state NMR by unifying dipolar and quadrupolar interactions and highlights the unique features offered by solid-state 2H NMR with experimental illustrations. For randomly oriented multilamellar lipids or aligned membranes, solid-state 2H NMR enables direct measurement of residual quadrupolar couplings (RQCs) due to individual C-2H-labeled segments. The distribution of RQC values gives nearly complete profiles of the segmental order parameters SCD(i) as a function of acyl segment position (i). Alternatively, one can measure residual dipolar couplings (RDCs) for natural abundance lipid samples to obtain segmental SCH order parameters. A theoretical mean-torque model provides acyl-packing profiles representing the cumulative chain extension along the normal to the aqueous interface. Equilibrium structural properties of fluid bilayers and various thermodynamic quantities can then be calculated, which describe the interactions with cholesterol, detergents, peptides, and integral membrane proteins and formation of lipid rafts. One can also obtain direct information for membrane-bound peptides or proteins by measuring RDCs using magic-angle spinning (MAS) in combination with dipolar recoupling methods. Solid-state NMR methods have been extensively applied to characterize model membranes and membrane-bound peptides and proteins, giving unique information on their conformations, orientations, and interactions in the natural liquid-crystalline state.
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Affiliation(s)
- Trivikram R Molugu
- Department of Chemistry & Biochemistry and ‡Department of Physics, University of Arizona , Tucson, Arizona 85721, United States
| | - Soohyun Lee
- Department of Chemistry & Biochemistry and ‡Department of Physics, University of Arizona , Tucson, Arizona 85721, United States
| | - Michael F Brown
- Department of Chemistry & Biochemistry and ‡Department of Physics, University of Arizona , Tucson, Arizona 85721, United States
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9
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Abstract
Site-directed spin labeling (SDSL) in combination with electron paramagnetic resonance (EPR) spectroscopy is a well-established method that has recently grown in popularity as an experimental technique, with multiple applications in protein and peptide science. The growth is driven by development of labeling strategies, as well as by considerable technical advances in the field, that are paralleled by an increased availability of EPR instrumentation. While the method requires an introduction of a paramagnetic probe at a well-defined position in a peptide sequence, it has been shown to be minimally destructive to the peptide structure and energetics of the peptide-membrane interactions. In this chapter, we describe basic approaches for using SDSL EPR spectroscopy to study interactions between small peptides and biological membranes or membrane mimetic systems. We focus on experimental approaches to quantify peptide-membrane binding, topology of bound peptides, and characterize peptide aggregation. Sample preparation protocols including spin-labeling methods and preparation of membrane mimetic systems are also described.
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Affiliation(s)
- Tatyana I Smirnova
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, USA.
| | - Alex I Smirnov
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, USA
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10
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Huster D. Solid-state NMR spectroscopy to study protein-lipid interactions. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:1146-60. [PMID: 24333800 DOI: 10.1016/j.bbalip.2013.12.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 12/04/2013] [Indexed: 12/22/2022]
Abstract
The appropriate lipid environment is crucial for the proper function of membrane proteins. There is a tremendous variety of lipid molecules in the membrane and so far it is often unclear which component of the lipid matrix is essential for the function of a respective protein. Lipid molecules and proteins mutually influence each other; parameters such as acyl chain order, membrane thickness, membrane elasticity, permeability, lipid-domain and annulus formation are strongly modulated by proteins. More recent data also indicates that the influence of proteins goes beyond a single annulus of next-neighbor boundary lipids. Therefore, a mesoscopic approach to membrane lipid-protein interactions in terms of elastic membrane deformations has been developed. Solid-state NMR has greatly contributed to the understanding of lipid-protein interactions and the modern view of biological membranes. Methods that detect the influence of proteins on the membrane as well as direct lipid-protein interactions have been developed and are reviewed here. Examples for solid-state NMR studies on the interaction of Ras proteins, the antimicrobial peptide protegrin-1, the G protein-coupled receptor rhodopsin, and the K(+) channel KcsA are discussed. This article is part of a Special Issue entitled Tools to study lipid functions.
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Affiliation(s)
- Daniel Huster
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, D-04107 Leipzig, Germany.
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11
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Babilon S, Mörl K, Beck-Sickinger AG. Towards improved receptor targeting: anterograde transport, internalization and postendocytic trafficking of neuropeptide Y receptors. Biol Chem 2013; 394:921-36. [DOI: 10.1515/hsz-2013-0123] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Accepted: 02/22/2013] [Indexed: 01/10/2023]
Abstract
Abstract
The neuropeptide Y system is known to be involved in the regulation of many central physiological and pathophysiological processes, such as energy homeostasis, obesity, cancer, mood disorders and epilepsy. Four Y receptor subtypes have been cloned from human tissue (hY1, hY2, hY4 and hY5) that form a multiligand/multireceptor system together with their three peptidic agonists (NPY, PYY and PP). Addressing this system for medical application requires on the one hand detailed information about the receptor-ligand interaction to design subtype-selective compounds. On the other hand comprehensive knowledge about alternative receptor signaling, as well as desensitization, localization and downregulation is crucial to circumvent the development of undesired side-effects and drug resistance. By bringing such knowledge together, highly potent and long-lasting drugs with minimized side-effects can be engineered. Here, current knowledge about Y receptor export, internalization, recycling, and degradation is summarized, with a focus on the human Y receptor subtypes, and is discussed in terms of its impact on therapeutic application.
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12
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Weizenmann N, Huster D, Scheidt HA. Interaction of local anesthetics with lipid bilayers investigated by 1H MAS NMR spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:3010-8. [DOI: 10.1016/j.bbamem.2012.07.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 07/16/2012] [Accepted: 07/19/2012] [Indexed: 11/25/2022]
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13
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The spin label amino acid TOAC and its uses in studies of peptides: chemical, physicochemical, spectroscopic, and conformational aspects. Biophys Rev 2012; 4:45-66. [PMID: 22347893 PMCID: PMC3271205 DOI: 10.1007/s12551-011-0064-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 12/20/2011] [Indexed: 01/21/2023] Open
Abstract
We review work on the paramagnetic amino acid 2,2,6,6-tetramethyl-N-oxyl-4-amino-4-carboxylic acid, TOAC, and its applications in studies of peptides and peptide synthesis. TOAC was the first spin label probe incorporated in peptides by means of a peptide bond. In view of the rigid character of this cyclic molecule and its attachment to the peptide backbone via a peptide bond, TOAC incorporation has been very useful to analyze backbone dynamics and peptide secondary structure. Many of these studies were performed making use of EPR spectroscopy, but other physical techniques, such as X-ray crystallography, CD, fluorescence, NMR, and FT-IR, have been employed. The use of double-labeled synthetic peptides has allowed the investigation of their secondary structure. A large number of studies have focused on the interaction of peptides, both synthetic and biologically active, with membranes. In the latter case, work has been reported on ligands and fragments of GPCR, host defense peptides, phospholamban, and β-amyloid. EPR studies of macroscopically aligned samples have provided information on the orientation of peptides in membranes. More recent studies have focused on peptide–protein and peptide–nucleic acid interactions. Moreover, TOAC has been shown to be a valuable probe for paramagnetic relaxation enhancement NMR studies of the interaction of labeled peptides with proteins. The growth of the number of TOAC-related publications suggests that this unnatural amino acid will find increasing applications in the future.
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14
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Parker MS, Sah R, Balasubramaniam A, Sallee FR, Zerbe O, Parker SL. Non-specific binding and general cross-reactivity of Y receptor agonists are correlated and should importantly depend on their acidic sectors. Peptides 2011; 32:258-65. [PMID: 21126552 PMCID: PMC3025077 DOI: 10.1016/j.peptides.2010.11.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2010] [Revised: 11/12/2010] [Accepted: 11/12/2010] [Indexed: 10/18/2022]
Abstract
Non-specific binding of Y receptor agonists to intact CHO cells, and to CHO cell or rat brain particulates, is much greater for human neuropeptide Y (hNPY) compared to porcine peptide Y (pPYY), and especially relative to human pancreatic polypeptide (hPP). This binding of hNPY is reduced by alkali cations in preference to non-ionic chaotrope urea, while the much lower non-specific binding of pPYY is more sensitive to urea. The difference could mainly be due to the 10-16 stretch in 36-residue Y agonists (residues 8-14 in N-terminally clipped 34-peptides), located in the sector that contains all acidic residues of physiological Y agonists. Anionic pairs containing aspartate in the 10-16 zone could be principally responsible for non-specific attachments, but may also aid the receptor site binding. Two such pairs are found in hNPY, one in pPYY, and none in hPP. The hydroxyl amino acid residue at position 13 in mammalian PYY and PP molecules could lower conformational plasticity and the non-selective binding via intrachain hydrogen bonding. The acidity of this tract could also be important in agonist selectivity of the Y receptor subtypes. The differences point to an evolutionary reduction of promiscuous protein binding from NPY to PP, and should also be important for Y agonist selectivity within NPY receptor group, and correlate with partial agonism and out-of group cross-reactivity with other receptors.
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Affiliation(s)
- M. S. Parker
- Department. of Molecular Cell Sciences, Univ. of Memphis, Memphis, TN 38152, USA
| | - R. Sah
- Department of Surgery, Univ. of Cincinnati, Cincinnati, OH 45267, USA
| | - A. Balasubramaniam
- Department of Psychiatry, Univ. of Cincinnati, Cincinnati, OH 45267, USA
| | - F. R. Sallee
- Department of Surgery, Univ. of Cincinnati, Cincinnati, OH 45267, USA
| | - O. Zerbe
- Department of Organic Chemistry, Univ. of Basel, Basel, CH-8057, Switzerland
| | - S. L. Parker
- Department of Pharmacology, Univ. of Tennessee Health Science Center, Memphis, TN 38163, USA
- Corresponding author at: Department of Pharmacology, UTHSC Memphis, Memphis TN 38163, USA,
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15
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Schmidt P, Lindner D, Montag C, Berndt S, Beck-Sickinger AG, Rudolph R, Huster D. Prokaryotic expression, in vitro folding, and molecular pharmacological characterization of the neuropeptide Y receptor type 2. Biotechnol Prog 2010; 25:1732-9. [PMID: 19725122 DOI: 10.1002/btpr.266] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
G protein-coupled receptors (GPCRs) are a class of membrane proteins that represent a major target for pharmacological developments. However, there is still little knowledge about GPCR structure and dynamics since high-level expression and characterization of active GPCRs in vitro is extremely complicated. Here, we describe the recombinant expression and functional folding of the human Y(2) receptor from inclusion bodies of E. coli cultures. Milligram protein quantities were produced using high density fermentation and isolated in a single step purification with a yield of over 20 mg/L culture. Extensive studies were carried out on in vitro refolding and stabilization of the isolated receptor in detergent solution. The specific binding of the ligand, the 36 residue neuropeptide Y (NPY), to the recombinant Y(2) receptors in micellar form was shown by several radioligand affinity assays. In competition experiments, an IC(50) value in low nanomolar range could be determined. Further, a K(D) value of 1.9 nM was determined from a saturation assay, where NPY was titrated to the recombinant Y(2) receptors.
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Affiliation(s)
- Peter Schmidt
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstrasse 16-18, D-04107 Leipzig, Germany
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Parameters modulating the maximum insertion pressure of proteins and peptides in lipid monolayers. Biochimie 2009; 91:718-33. [DOI: 10.1016/j.biochi.2009.03.018] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 03/25/2009] [Indexed: 11/18/2022]
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Thomas L, Scheidt HA, Bettio A, Beck-Sickinger AG, Huster D, Zschörnig O. The interaction of neuropeptide Y with negatively charged and zwitterionic phospholipid membranes. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2009; 38:663-77. [PMID: 19319516 DOI: 10.1007/s00249-009-0423-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Revised: 01/25/2009] [Accepted: 02/15/2009] [Indexed: 10/21/2022]
Abstract
The interaction of the 36 amino acid neuropeptide Y (NPY) with liposomes was studied using the intrinsic tyrosine fluorescence of NPY and an NPY fragment comprising amino acids 18-36. The vesicular membranes were composed of phosphatidylcholine and phosphatidylserine at varying mixing ratios. From the experimentally measured binding curves, the standard Gibbs free energy for the peptide transfer from aqueous solution to the lipid membrane was calculated to be around -30 kJ/mol for membrane mixtures containing physiological amounts of acidic lipids at pH 5. The effective charge of the peptide depends on the pH of the buffer and is about half of its theoretical net charge. The results were confirmed using the fluorescence of the NPY analogue [Trp(32)]-NPY. Further, the position of NPY's alpha-helix in the membrane was estimated from the intrinsic tyrosine fluorescence of NPY, from quenching experiments with spin-labelled phospholipids using [Trp(32)]-NPY, and from (1)H magic-angle spinning NMR relaxation measurements using spin-labelled [Ala(31), TOAC(32)]-NPY. The results suggest that the immersion depth of NPY into the membrane is triggered by the membrane composition. The alpha-helix of NPY is located in the upper chain region of zwitterionic membranes but its position is shifted to the glycerol region in negatively charged membranes. For membranes composed of phosphatidylcholine and phosphatidylserine, an intermediate position of the alpha-helix is observed.
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Affiliation(s)
- Lars Thomas
- Institute of Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany
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Dyck M, Lösche M. Interaction of the neurotransmitter, neuropeptide Y, with phospholipid membranes: film balance and fluorescence microscopy studies. J Phys Chem B 2007; 110:22143-51. [PMID: 17078650 PMCID: PMC2553689 DOI: 10.1021/jp056697y] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The association of neuropeptide Y (NPY) with air-water interfaces and with phospholipid monolayers on water subphases and on physiological buffer has been investigated. Surface pressure (pi) versus molecular area (A) relations of the peptide at water surfaces depend on the concentration of the spreading solutions. Independent of that concentration, they show a transition from a low-density state to a high-density state at pi approximately 12 mN/m. Similar features are observed in the NPY adsorption to preformed monolayers (Deltapi(t --> infinity) as a function of pii = pi (t = 0) where t = 0 signifies the time of peptide injection). The transition is also observed in cospread lipid-NPY monolayers and is interpreted as the exclusion of the peptide from the surface layer. The reproducibility of the isotherms after expansion suggests that cospread lipid-peptide monolayers are thermodynamically stable and that the peptide remains associated with the monolayer after exclusion from the lipid surface. A comparison of NPY association with zwitterionic and with anionic lipids as well as a comparison of the interactions on pure water and on physiological buffer suggest that electrostatic attraction plays a major role in the energetics of peptide binding to the membrane surface. Dual label fluorescence microscopy demonstrates that the peptide associates preferentially with the disordered, liquid condensed monolayer phase and also suggests that it self-aggregates upon exceeding a critical surface concentration. A NPY variant with a distorted alpha-helix interacts with the surface as strongly as the natural NPY but expands the monolayers more. This suggests that the helix motif in the peptide is more important for the interaction with the receptor than for binding of the peptide to the membrane surface. In context, these observations attribute a specific role to the membrane in funneling the signal peptide to its membrane receptor.
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Gabriel GJ, Som A, Madkour AE, Eren T, Tew GN. Infectious Disease: Connecting Innate Immunity to Biocidal Polymers. MATERIALS SCIENCE & ENGINEERING. R, REPORTS : A REVIEW JOURNAL 2007; 57:28-64. [PMID: 18160969 PMCID: PMC2153456 DOI: 10.1016/j.mser.2007.03.002] [Citation(s) in RCA: 196] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Infectious disease is a critically important global healthcare issue. In the U.S. alone there are 2 million new cases of hospital-acquired infections annually leading to 90,000 deaths and 5 billion dollars of added healthcare costs. Couple these numbers with the appearance of new antibiotic resistant bacterial strains and the increasing occurrences of community-type outbreaks, and clearly this is an important problem. Our review attempts to bridge the research areas of natural host defense peptides (HDPs), a component of the innate immune system, and biocidal cationic polymers. Recently discovered peptidomimetics and other synthetic mimics of HDPs, that can be short oligomers as well as polymeric macromolecules, provide a unique link between these two areas. An emerging class of these mimics are the facially amphiphilic polymers that aim to emulate the physicochemical properties of HDPs but take advantage of the synthetic ease of polymers. These mimics have been designed with antimicrobial activity and, importantly, selectivity that rivals natural HDPs. In addition to providing some perspective on HDPs, selective mimics, and biocidal polymers, focus is given to the arsenal of biophysical techniques available to study their mode of action and interactions with phospholipid membranes. The issue of lipid type is highlighted and the important role of negative curvature lipids is illustrated. Finally, materials applications (for instance, in the development of permanently antibacterial surfaces) are discussed as this is an important part of controlling the spread of infectious disease.
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Affiliation(s)
- Gregory J Gabriel
- Polymer Science & Engineering Department, University of Massachusetts, 120 Governors Drive, Amherst, MA 01003
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Peggion C, Jost M, Baldini C, Formaggio F, Toniolo C. Total syntheses in solution of TOAC-labelled alamethicin F50/5 analogues. Chem Biodivers 2007; 4:1183-99. [PMID: 17589860 DOI: 10.1002/cbdv.200790104] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Total syntheses in solution of a set of four selected analogues of the 19-mer component F50/5 of alamethicin, the most extensively studied among the channel-former peptaibol antibiotics, are planned and reported. All analogues bear three Glu(OMe) residues, replacing the Gln residues at positions 7, 18, and 19 of the naturally occurring compound. Three analogues are mono-labelled with the free-radical-containing amino acid residue TOAC at the strategic positions 1, 8, or 16. The fourth analogue is bis-labelled with the same EPR-active residue at both positions 1 and 16. In the native sequence, all of the positions where TOAC replacements have been introduced are characterized by residues of Aib, the prototype of the class of helicogenic C(alpha)-tetrasubstituted alpha-amino acids. All of the TOAC analogues synthesized exhibit significant membrane-modifying properties.
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Affiliation(s)
- Cristina Peggion
- Institute of Biomolecular Chemistry, Padova Unit, CNR, Department of Chemistry, University of Padova, Padova, Italy
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Lomize AL, Pogozheva ID, Lomize MA, Mosberg HI. The role of hydrophobic interactions in positioning of peripheral proteins in membranes. BMC STRUCTURAL BIOLOGY 2007; 7:44. [PMID: 17603894 PMCID: PMC1934363 DOI: 10.1186/1472-6807-7-44] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Accepted: 06/29/2007] [Indexed: 02/05/2023]
Abstract
BACKGROUND Three-dimensional (3D) structures of numerous peripheral membrane proteins have been determined. Biological activity, stability, and conformations of these proteins depend on their spatial positions with respect to the lipid bilayer. However, these positions are usually undetermined. RESULTS We report the first large-scale computational study of monotopic/peripheral proteins with known 3D structures. The optimal translational and rotational positions of 476 proteins are determined by minimizing energy of protein transfer from water to the lipid bilayer, which is approximated by a hydrocarbon slab with a decadiene-like polarity and interfacial regions characterized by water-permeation profiles. Predicted membrane-binding sites, protein tilt angles and membrane penetration depths are consistent with spin-labeling, chemical modification, fluorescence, NMR, mutagenesis, and other experimental studies of 53 peripheral proteins and peptides. Experimental membrane binding affinities of peripheral proteins were reproduced in cases that did not involve a helix-coil transition, specific binding of lipids, or a predominantly electrostatic association. Coordinates of all examined peripheral proteins and peptides with the calculated hydrophobic membrane boundaries, subcellular localization, topology, structural classification, and experimental references are available through the Orientations of Proteins in Membranes (OPM) database. CONCLUSION Positions of diverse peripheral proteins and peptides in the lipid bilayer can be accurately predicted using their 3D structures that represent a proper membrane-bound conformation and oligomeric state, and have membrane binding elements present. The success of the implicit solvation model suggests that hydrophobic interactions are usually sufficient to determine the spatial position of a protein in the membrane, even when electrostatic interactions or specific binding of lipids are substantial. Our results demonstrate that most peripheral proteins not only interact with the membrane surface, but penetrate through the interfacial region and reach the hydrocarbon interior, which is consistent with published experimental studies.
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Affiliation(s)
- Andrei L Lomize
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109-1065, USA
| | - Irina D Pogozheva
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109-1065, USA
| | - Mikhail A Lomize
- College of Literature, Science and the Arts, University of Michigan, Ann Arbor, MI 48109-1065, USA
| | - Henry I Mosberg
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109-1065, USA
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Sobota JA, Ferraro F, Bäck N, Eipper BA, Mains RE. Not all secretory granules are created equal: Partitioning of soluble content proteins. Mol Biol Cell 2006; 17:5038-52. [PMID: 17005911 PMCID: PMC1761688 DOI: 10.1091/mbc.e06-07-0626] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Secretory granules carrying fluorescent cargo proteins are widely used to study granule biogenesis, maturation, and regulated exocytosis. We fused the soluble secretory protein peptidylglycine alpha-hydroxylating monooxygenase (PHM) to green fluorescent protein (GFP) to study granule formation. When expressed in AtT-20 or GH3 cells, the PHM-GFP fusion protein partitioned from endogenous hormone (adrenocorticotropic hormone, growth hormone) into separate secretory granule pools. Both exogenous and endogenous granule proteins were stored and released in response to secretagogue. Importantly, we found that segregation of content proteins is not an artifact of overexpression nor peculiar to GFP-tagged proteins. Neither luminal acidification nor cholesterol-rich membrane microdomains play essential roles in soluble content protein segregation. Our data suggest that intrinsic biophysical properties of cargo proteins govern their differential sorting, with segregation occurring during the process of granule maturation. Proteins that can self-aggregate are likely to partition into separate granules, which can accommodate only a few thousand copies of any content protein; proteins that lack tertiary structure are more likely to distribute homogeneously into secretory granules. Therefore, a simple "self-aggregation default" theory may explain the little acknowledged, but commonly observed, tendency for both naturally occurring and exogenous content proteins to segregate from each other into distinct secretory granules.
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Affiliation(s)
- Jacqueline A. Sobota
- *Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030-3401; and
| | - Francesco Ferraro
- *Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030-3401; and
| | - Nils Bäck
- Department of Anatomy, Institute of Biomedicine, University of Helsinki, FIN-00014, Helsinki, Finland
| | - Betty A. Eipper
- *Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030-3401; and
| | - Richard E. Mains
- *Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030-3401; and
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Krüger A, Liang Y, Jarre G, Stegk J. Surface functionalisation of detonation diamond suitable for biological applications. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b601325b] [Citation(s) in RCA: 278] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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