1
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The thermodynamic and kinetic mechanisms of a Ganoderma lucidum proteoglycan inhibiting hIAPP amyloidosis. Biophys Chem 2021; 280:106702. [PMID: 34741991 DOI: 10.1016/j.bpc.2021.106702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 10/17/2021] [Accepted: 10/26/2021] [Indexed: 12/14/2022]
Abstract
Ganoderma lucidum is a valuable medicinal herbal which has been reported to prevent type 2 diabetes (T2D). A natural hyperbranched proteoglycan extracted from Ganoderma lucidum, namely, FYGL, has been demonstrated to inhibit the amyloidosis of human islet amyloid polypeptide (hIAPP) previously by our lab. However, the effective active components and the mechanisms of FYGL in inhibiting hIAPP amyloidosis are unknown. To identify the effective active components, different components from FYGL were isolated: the polysaccharide FYGL-1, the proteoglycans of FYGL-2 and FYGL-3. We further separated and sequenced the protein moieties of FYGL-2 and FYGL-3, namely, FYGL-2-P and FYGL-3-P, respectively, and compared their abilities to inhibit hIAPP amyloidosis, and systematically explored the inhibitory mechanisms by spectroscopy, microscopy and molecular dynamic simulation methods. Results showed that the protein moieties of FYGL played essential roles in inhibiting hIAPP amyloidosis. The strong, specific, and enthalpy-driven interaction by π-π stacking and electrostatic forces between hIAPP and FYGL-3-P dramatically inhibited hIAPP amyloidosis. These results suggested that FYGL-3-P had enormous potential to prevent hIAPP misfolding-induced diabetes and structurally helped researchers to seek or design inhibitors against polypeptide amyloidosis.
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2
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Hoang HN, Wu C, Hill TA, Dantas de Araujo A, Bernhardt PV, Liu L, Fairlie DP. A Novel Long‐Range n to π* Interaction Secures the Smallest known α‐Helix in Water. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201911277] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Huy N. Hoang
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Chongyang Wu
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Timothy A. Hill
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Aline Dantas de Araujo
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane Qld 4072 Australia
| | - Ligong Liu
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
| | - David P. Fairlie
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging Institute for Molecular Bioscience The University of Queensland Brisbane QLD 4072 Australia
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3
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Hoang HN, Wu C, Hill TA, Dantas de Araujo A, Bernhardt PV, Liu L, Fairlie DP. A Novel Long-Range n to π* Interaction Secures the Smallest known α-Helix in Water. Angew Chem Int Ed Engl 2019; 58:18873-18877. [PMID: 31625253 DOI: 10.1002/anie.201911277] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/10/2019] [Indexed: 12/17/2022]
Abstract
The introduction of an amide bond linking side chains of the first and fifth amino acids forms a cyclic pentapeptide that optimally stabilizes the smallest known α-helix in water. The origin of the stabilization is unclear. The observed dependence of α-helicity on the solvent and cyclization linker led us to discover a novel long-range n to π* interaction between a main-chain amide oxygen and a uniquely positioned carbonyl group in the linker of cyclic pentapeptides. CD and NMR spectra, NMR and X-ray structures, modelling, and MD simulations reveal that this first example of a synthetically incorporated long-range n to π* CO⋅⋅⋅Cγ =Ο interaction uniquely enforces an almost perfect and remarkably stable peptide α-helix in water but not in DMSO. This unusual interaction with a covalent amide bond outside the helical backbone suggests new approaches to synthetically stabilize peptide structures in water.
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Affiliation(s)
- Huy N Hoang
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Chongyang Wu
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Timothy A Hill
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Aline Dantas de Araujo
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld, 4072, Australia
| | - Ligong Liu
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - David P Fairlie
- Division of Chemistry and Structural Biology and ARC Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
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4
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Ehrenmann J, Schöppe J, Klenk C, Plückthun A. New views into class B GPCRs from the crystal structure of PTH1R. FEBS J 2019; 286:4852-4860. [PMID: 31670461 DOI: 10.1111/febs.15115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/28/2019] [Accepted: 10/29/2019] [Indexed: 11/29/2022]
Abstract
The parathyroid hormone 1 receptor (PTH1R) is a major regulator of mineral ion homeostasis and bone metabolism and is thus considered an attractive drug target for the treatment of disorders in calcium metabolism and bone-related diseases such as osteoporosis. PTH1R is a member of the class B of GPCRs, which all share a dynamic multidomain binding mechanism to the peptide hormone. For a long time, these complexes have been recalcitrant to structural studies despite their great therapeutic relevance. Through extensive engineering of both the receptor and the peptide agonist ligand, we were able to determine the first high-resolution structure of a PTH1R-agonist complex. Comparisons of the PTH1R crystal structure with subsequently reported cryo-electron microscopy structures of the same receptor in complex with a G protein, as well as with other class B GPCR structures bound to antagonists, reveal new insights into the two-step activation mechanism of class B GPCRs and extend our understanding of the precise molecular rearrangements during receptor activation.
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Affiliation(s)
- Janosch Ehrenmann
- Department of Biochemistry, University of Zürich, Zürich, Switzerland
| | - Jendrik Schöppe
- Department of Biochemistry, University of Zürich, Zürich, Switzerland
| | - Christoph Klenk
- Department of Biochemistry, University of Zürich, Zürich, Switzerland
| | - Andreas Plückthun
- Department of Biochemistry, University of Zürich, Zürich, Switzerland
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5
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High-resolution crystal structure of parathyroid hormone 1 receptor in complex with a peptide agonist. Nat Struct Mol Biol 2018; 25:1086-1092. [PMID: 30455434 DOI: 10.1038/s41594-018-0151-4] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 10/08/2018] [Indexed: 01/14/2023]
Abstract
Parathyroid hormone 1 receptor (PTH1R) is a class B multidomain G-protein-coupled receptor (GPCR) that controls calcium homeostasis. Two endogenous peptide ligands, parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP), activate the receptor, and their analogs teriparatide and abaloparatide are used in the clinic to increase bone formation as an effective yet costly treatment for osteoporosis. Activation of PTH1R involves binding of the peptide ligand to the receptor extracellular domain (ECD) and transmembrane domain (TMD), a hallmark of class B GPCRs. Here, we present the crystal structure of human PTH1R in complex with a peptide agonist at 2.5-Å resolution, allowing us to delineate the agonist binding mode for this receptor and revealing molecular details within conserved structural motifs that are critical for class B receptor function. Thus, this study provides structural insight into the function of PTH1R and extends our understanding of this therapeutically important class of GPCRs.
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6
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Xu W, Lau YH, Fischer G, Tan YS, Chattopadhyay A, de la Roche M, Hyvönen M, Verma C, Spring DR, Itzhaki LS. Macrocyclized Extended Peptides: Inhibiting the Substrate-Recognition Domain of Tankyrase. J Am Chem Soc 2017; 139:2245-2256. [PMID: 28084734 PMCID: PMC5358875 DOI: 10.1021/jacs.6b10234] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Indexed: 12/25/2022]
Abstract
We report a double-click macrocyclization approach for the design of constrained peptide inhibitors having non-helical or extended conformations. Our targets are the tankyrase proteins (TNKS), poly(ADP-ribose) polymerases (PARP) that regulate Wnt signaling by targeting Axin for degradation. TNKS are deregulated in many different cancer types, and inhibition of TNKS therefore represents an attractive therapeutic strategy. However, clinical development of TNKS-specific PARP catalytic inhibitors is challenging due to off-target effects and cellular toxicity. We instead targeted the substrate-recognition domain of TNKS, as it is unique among PARP family members. We employed a two-component strategy, allowing peptide and linker to be separately engineered and then assembled in a combinatorial fashion via click chemistry. Using the consensus substrate-peptide sequence as a starting point, we optimized the length and rigidity of the linker and its position along the peptide. Optimization was further guided by high-resolution crystal structures of two of the macrocyclized peptides in complex with TNKS. This approach led to macrocyclized peptides with submicromolar affinities for TNKS and high proteolytic stability that are able to disrupt the interaction between TNKS and Axin substrate and to inhibit Wnt signaling in a dose-dependent manner. The peptides therefore represent a promising starting point for a new class of substrate-competitive inhibitors of TNKS with potential for suppressing Wnt signaling in cancer. Moreover, by demonstrating the application of the double-click macrocyclization approach to non-helical, extended, or irregularly structured peptides, we greatly extend its potential and scope, especially given the frequency with which such motifs mediate protein-protein interactions.
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Affiliation(s)
- Wenshu Xu
- Department
of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Yu Heng Lau
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Gerhard Fischer
- Department
of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, United Kingdom
| | - Yaw Sing Tan
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
- Bioinformatics
Institute, Agency for Science, Technology
and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix 138671, Singapore
| | - Anasuya Chattopadhyay
- Department
of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Marc de la Roche
- Department
of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, United Kingdom
| | - Marko Hyvönen
- Department
of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, United Kingdom
| | - Chandra Verma
- Bioinformatics
Institute, Agency for Science, Technology
and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix 138671, Singapore
- School
of Biological Sciences, Nanyang Technological
University, 60 Nanyang
Drive 637551, Singapore
- Department
of Biological Sciences, National University
of Singapore, 14 Science
Drive 4 117543, Singapore
| | - David R. Spring
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Laura S. Itzhaki
- Department
of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
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7
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Vasco AV, Pérez CS, Morales FE, Garay HE, Vasilev D, Gavín JA, Wessjohann LA, Rivera DG. Macrocyclization of Peptide Side Chains by the Ugi Reaction: Achieving Peptide Folding and Exocyclic N-Functionalization in One Shot. J Org Chem 2015; 80:6697-707. [DOI: 10.1021/acs.joc.5b00858] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Aldrin V. Vasco
- Center
for Natural Products Research, Faculty of Chemistry, University of Havana, Zapata y G, 10400, La Habana, Cuba
- Facultad
de Ingeniería Química, Instituto Superior Politécnico José Antonio Echeverría, CUJAE, Calle 114 # 11901, 11500, La Habana, Cuba
| | - Carlos S. Pérez
- Center
for Natural Products Research, Faculty of Chemistry, University of Havana, Zapata y G, 10400, La Habana, Cuba
| | - Fidel E. Morales
- Center
for Natural Products Research, Faculty of Chemistry, University of Havana, Zapata y G, 10400, La Habana, Cuba
| | - Hilda E. Garay
- Synthetic Peptides
Group, Center for Genetic Engineering and Biotechnology, P.O. Box 6162, La Habana, Cuba
| | - Dimitar Vasilev
- Department
of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120, Halle/Saale, Germany
| | - José A. Gavín
- Instituto
Universitario de Bioorgánica Antonio González and Departamento
de Química Orgánica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain
| | - Ludger A. Wessjohann
- Department
of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120, Halle/Saale, Germany
| | - Daniel G. Rivera
- Center
for Natural Products Research, Faculty of Chemistry, University of Havana, Zapata y G, 10400, La Habana, Cuba
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8
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Ganesh Kumar M, Mali SM, Raja KMP, Gopi HN. Design of Stable β-Hairpin Mimetics through Backbone Disulfide Bonds. Org Lett 2014; 17:230-3. [DOI: 10.1021/ol503310r] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mothukuri Ganesh Kumar
- Department
of Chemistry, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune 411008, India
| | - Sachitanand M. Mali
- Department
of Chemistry, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune 411008, India
| | - K. Muruga Poopathi Raja
- Department
of Physical Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai 625 021, India
| | - Hosahudya N. Gopi
- Department
of Chemistry, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune 411008, India
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9
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Muppidi A, Doi K, Ramil CP, Wang HG, Lin Q. Synthesis of cell-permeable stapled BH3 peptide-based Mcl-1 inhibitors containing simple aryl and vinylaryl cross-linkers. Tetrahedron 2014; 70:7740-7745. [PMID: 25267861 PMCID: PMC4175436 DOI: 10.1016/j.tet.2014.05.104] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We report the synthesis of a series of distance-matching aryl and vinylaryl cross-linkers for constructing stapled peptides containing cysteines at i,i+7 positions. Langevin dynamics simulation studies helped to classify these cross-linkers into two categories: the rigid cross-linkers with narrower S-S distance distribution and the flexible cross-linkers with wider S-S distance distribution. The stapled Noxa BH3 peptides with the flexible distance-matching cross-linkers gave the highest degree of helicity as well as the most potent inhibitory activity against Mcl-1. However, the stapled peptides with the highest hydrophobicity showed the most efficient cellular uptake. Together, this work illustrates the divergent nature of binding affinity and cellular uptake, and the vital importance of choosing appropriate cross-linkers in constructing stapled peptides with the drug-like properties.
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Affiliation(s)
- Avinash Muppidi
- Department of Chemistry, State University of New York at Buffalo, Buffalo, New York 14260, USA
| | - Kenichiro Doi
- Department of Pharmacology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
| | - Carlo P. Ramil
- Department of Chemistry, State University of New York at Buffalo, Buffalo, New York 14260, USA
| | - Hong-Gang Wang
- Department of Pharmacology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
| | - Qing Lin
- Department of Chemistry, State University of New York at Buffalo, Buffalo, New York 14260, USA
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10
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Haney CM, Horne WS. Oxime side-chain cross-links in an α-helical coiled-coil protein: structure, thermodynamics, and folding-templated synthesis of bicyclic species. Chemistry 2013; 19:11342-51. [PMID: 23843311 DOI: 10.1002/chem.201300506] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Indexed: 01/11/2023]
Abstract
Covalent side-chain cross-links are a versatile method to control peptide folding, particularly when α-helical secondary structure is the target. Here, we examine the application of oxime bridges, formed by the chemoselective reaction between aminooxy and aldehyde side chains, for the stabilization of a helical peptide involved in a protein-protein complex. A series of sequence variants of the dimeric coiled coil GCN4-p1 bearing oxime bridges at solvent-exposed positions were prepared and biophysically characterized. Triggered unmasking of a side-chain aldehyde in situ and subsequent cyclization proceed rapidly and cleanly at pH 7 in the folded protein complex. Comparison of folding thermodynamics among a series of different oxime bridges show that the cross links are consistently stabilizing to the coiled coil, with the extent of stabilization sensitive to the exact size and structure of the macrocycle. X-ray crystallographic analysis of a coiled coil with the best cross link in place and a second structure of its linear precursor show how the bridge is accommodated into an α-helix. Preparation of a bicyclic oligomer by simultaneous formation of two linkages in situ demonstrates the potential use of triggered oxime formation to both trap and stabilize a particular peptide folded conformation in the bound state.
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Affiliation(s)
- Conor M Haney
- Department of Chemistry, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, PA 15260, USA
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11
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Bock JE, Gavenonis J, Kritzer JA. Getting in shape: controlling peptide bioactivity and bioavailability using conformational constraints. ACS Chem Biol 2013; 8:488-499. [PMID: 23170954 PMCID: PMC4847942 DOI: 10.1021/cb300515u] [Citation(s) in RCA: 179] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Chemical biologists commonly seek out correlations between the physicochemical properties of molecules and their behavior in biological systems. However, a new paradigm is emerging for peptides in which conformation is recognized as the primary determinant of bioactivity and bioavailability. This review highlights an emerging body of work that directly addresses how a peptide's conformation controls its biological effects, cell penetration, and intestinal absorption. Based on this work, the dream of mimicking the potency and bioavailability of natural product peptides is getting closer to reality.
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Affiliation(s)
- Jonathan E. Bock
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Jason Gavenonis
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
| | - Joshua A. Kritzer
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155, United States
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12
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Yin H. Constrained peptides as miniature protein structures. ISRN BIOCHEMISTRY 2012; 2012:692190. [PMID: 25969758 PMCID: PMC4392992 DOI: 10.5402/2012/692190] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Accepted: 09/03/2012] [Indexed: 11/23/2022]
Abstract
This paper discusses the recent developments of protein engineering using both covalent and noncovalent bonds to constrain peptides, forcing them into designed protein secondary structures. These constrained peptides subsequently can be used as peptidomimetics for biological functions such as regulations of protein-protein interactions.
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Affiliation(s)
- Hang Yin
- Department of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado at Boulder, 596 University of Colorado at Boulder, Boulder, CO 80309-0596, USA
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13
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Kelley WP, Chen S, Floyd PD, Hu P, Kapsi SG, Kord AS, Sun M, Vogt FG. Analytical Characterization of an Orally-Delivered Peptide Pharmaceutical Product. Anal Chem 2012; 84:4357-72. [DOI: 10.1021/ac203478r] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Wayne P. Kelley
- Biopharmaceutical R&D, GlaxoSmithKline llc. 709 Swedeland Road, King of Prussia, Pennsylvania 19406, United States
| | - Shujun Chen
- Product Development, GlaxoSmithKline plc. 709 Swedeland Road, King of Prussia, Pennsylvania 19406, United
States
| | - Philip D. Floyd
- Product Development, GlaxoSmithKline plc. 5 Moore Drive, Research Triangle Park, North Carolina
27709, United States
| | - Ping Hu
- Biopharmaceutical R&D, GlaxoSmithKline llc. 709 Swedeland Road, King of Prussia, Pennsylvania 19406, United States
| | - Shiva G. Kapsi
- Product Development, GlaxoSmithKline plc. 1250, South Collegeville Road,
Collegeville, Pennsylvania 19426, United States
| | - Alireza S. Kord
- Product Development, GlaxoSmithKline plc. 709 Swedeland Road, King of Prussia, Pennsylvania 19406, United
States
| | - Mingjiang Sun
- Product Development, GlaxoSmithKline plc. 709 Swedeland Road, King of Prussia, Pennsylvania 19406, United
States
| | - Frederick G. Vogt
- Product Development, GlaxoSmithKline plc. 709 Swedeland Road, King of Prussia, Pennsylvania 19406, United
States
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14
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Abraham-Nordling M, Persson B, Nordling E. Model of the complex of Parathyroid hormone-2 receptor and Tuberoinfundibular peptide of 39 residues. BMC Res Notes 2010; 3:270. [PMID: 20979597 PMCID: PMC2991341 DOI: 10.1186/1756-0500-3-270] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 10/27/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND We aim to propose interactions between the parathyroid hormone-2 receptor (PTH2R) and its ligand the tuberoinfundibular peptide of 39 residues (TIP39) by constructing a homology model of their complex. The two related peptides parathyroid hormone (PTH) and parathyroid hormone related protein (PTHrP) are compared with the complex to examine their interactions. FINDINGS In the model, the hydrophobic N-terminus of TIP39 is buried in a hydrophobic part of the central cavity between helices 3 and 7. Comparison of the peptide sequences indicates that the main discriminator between the agonistic peptides TIP39 and PTH and the inactive PTHrP is a tryptophan-phenylalanine replacement. The model indicates that the smaller phenylalanine in PTHrP does not completely occupy the binding site of the larger tryptophan residue in the other peptides. As only TIP39 causes internalisation of the receptor and the primary difference being an aspartic acid in position 7 of TIP39 that interacts with histidine 396 in the receptor, versus isoleucine/histidine residues in the related hormones, this might be a trigger interaction for the events that cause internalisation. CONCLUSIONS A model is constructed for the complex and a trigger interaction for full agonistic activation between aspartic acid 7 of TIP39 and histidine 396 in the receptor is proposed.
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Affiliation(s)
- Mirna Abraham-Nordling
- Division of Surgery, Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden.
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15
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Grauer A, König B. Peptidomimetics – A Versatile Route to Biologically Active Compounds. European J Org Chem 2009. [DOI: 10.1002/ejoc.200900599] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Andreas Grauer
- Institute für Organische Chemie, Universität Regensburg, 93040 Regensburg, Germany, Fax: +49‐941‐943‐1717
| | - Burkhard König
- Institute für Organische Chemie, Universität Regensburg, 93040 Regensburg, Germany, Fax: +49‐941‐943‐1717
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16
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Garner J, Harding MM. Design and synthesis of alpha-helical peptides and mimetics. Org Biomol Chem 2007; 5:3577-85. [PMID: 17971985 DOI: 10.1039/b710425a] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The alpha-helix is the most abundant secondary structural element in proteins and is an important structural domain for mediating protein-protein and protein-nucleic acid interactions. Strategies for the rational design and synthesis of alpha-helix mimetics have not matured as well as other secondary structure mimetics such as strands and turns. This perspective will focus on developments in the design, synthesis and applications of alpha-helices and mimetics, particularly in the last 5 years. Examples where synthetic compounds have delivered promising biological results will be highlighted as well as opportunities for the design of mimetics of the type I alpha-helical antifreeze proteins.
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Affiliation(s)
- James Garner
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
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17
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Potetinova Z, Barbier JR, Suen T, Dean T, Gardella TJ, Willick GE. C-terminal analogues of parathyroid hormone: effect of C-terminus function on helical structure, stability, and bioactivity. Biochemistry 2006; 45:11113-21. [PMID: 16964972 DOI: 10.1021/bi060500q] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have studied the effects of C-terminal group modifications (amide, methylamide, dimethylamide, aldehyde, and alcohol) on the conformation, adenylyl cyclase stimulation (AC), or binding of parathyroid hormone (hPTH) analogues, hPTH(1-28)NH(2) and hPTH(1-31)NH(2). hPTH(1-31)NH(2) has a C-terminal alpha-helix bounded by residues 17-29 [Chen, Z., et al. (2000) Biochemistry 39, 12766]. In both cases, relative to the natural analogue with a carboxyl C-terminus, the amide and methylamide had increased helix content whereas the dimethylamide forms had CD spectra more similar to the carboxyl one. Conformational effects were more pronounced with hPTH(1-28) than with hPTH(1-31), with increases in helix content of approximately 30% in contrast to 10%. Stabilization of the C-terminal helix of residues 1-28 seemed to correlate with an ability of the C-terminal function to H-bond appropriately. None of the analogues affected the AC stimulating activity significantly, but there was an up to 15-fold decrease in the level of apparent binding of the carboxyl hPTH(1-28) analogue compared to that of the methylamide and a 4-fold decrease in the level of binding of the aldehyde or dimethylamide. There was no significant change in binding activities for the 1-31 analogues. These observations are consistent with previous studies that imply the importance of a region of the hormone's C-terminal alpha-helix for tight binding to the receptor. They also show that modulation of helix stability does have an effect on the binding of the hormone, but only when the C-terminus is at the putative end of the helix. The similarity of AC stimulation even when binding changed 10-fold can be explained by assuming greater efficacy of the weaker binding PTH-receptor complexes in stimulating AC.
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Affiliation(s)
- Zhanna Potetinova
- Institute for Biological Sciences, National Research Council, Ottawa, Ontario, Canada K1A 0R6
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Scian M, Marin M, Bellanda M, Tou L, Alexander JM, Rosenblatt M, Chorev M, Peggion E, Mammi S. Backbone dynamics of human parathyroid hormone (1-34): flexibility of the central region under different environmental conditions. Biopolymers 2006; 84:147-60. [PMID: 16123988 DOI: 10.1002/bip.20355] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The presence of a stable tertiary structure in the bioactive N-terminal portion of parathyroid hormone (PTH), a major hormone in the maintenance of extracellular calcium homeostasis, is still debated. In this work, 15N relaxation parameters of the 33 backbone amides of human PTH(1-34) were determined in phosphate-buffered saline solution (PBS) and in the presence of dodecylphosphocholine (DPC) micelles. The relaxation parameters were analyzed using both the model-free formalism (G. Lipari and A. Szabo, Journal of the American Chemical Society, 1982, Vol. 104, pp. 4546-4549) and the reduced spectral density functions approach (J.-F. Lefevre, K. T. Dayie, J. W. Peng, and G. Wagner, Biochemistry, 1996, Vol. 35, pp. 2674-2686). In PBS, the region around Gly12 possesses a high degree of flexibility and the C-terminal helix is less flexible than the N-terminal one. In the presence of DPC micelles, the mobility of the entire molecule is reduced, but the stability of the N-terminal helix increases relative to the C-terminal one. A point of relatively higher mobility at residue Gly12 is still present and a new site of local mobility at residues 16-17 is generated. These results justify the lack of experimental nuclear Overhauser effect (NOE) restraints with lack of tertiary structure and support the hypothesis that, in the absence of the receptor, the relative spatial orientation of the two N- and C-terminal helices is undefined. The flexibility in the midregion of PTH(1-34), maintained in the presence of the membrane-mimetic environment, may enable the correct relative disposition of the two helices, favoring a productive interaction with the receptor.
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Affiliation(s)
- Michele Scian
- Institute of Biomolecular Chemistry, CNR, Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy
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19
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Rhee Y, Lee W, Lee EJ, Ma S, Park SY, Lim SK. In vitro and in vivo effect of parathyroid hormone analogue (1-14) containing -amino-iso-butyric acid residue (Aib)1,3. Yonsei Med J 2006; 47:214-22. [PMID: 16642551 PMCID: PMC2687631 DOI: 10.3349/ymj.2006.47.2.214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Firstly, parathyroid hormone (1-14) [PTH (1-14)] analogue containing various -amino-iso-butyric acid residue (Aib) was synthesized by exchanging the 1st and 3rd Ala residues of alpha carbon of PTH (1-14). This analogue revealed to have the quite tight and stable -helical structure using the nuclear magnetic resonance (NMR) analysis. The biological activities of these analogues were examined using a cAMP- generating assay in LLC-PK1 cell lines stably transfected with the wild- type human PTH1 receptor. Only the PTH analogue substituted with methyl moiety without acetylation showed significant cAMP generating action with 15.0 +/- 3.414 of EC50. Then, we used an ovariectomized rat model system to compare the in vivo effects of parathyroid hormone analogue with that of PTH (1-84). Daily subcutaneous administration of the unacetylated Aib1,3PTH (1-14) for 5 weeks in 30 nM/kg subcutaneously with positive control group receiving PTH (1-84) with 8 nM/ kg were performed. However, there was no significant change in spinal or femoral bone mineral density assessed by dual x-ray absorptiometry (DXA) in the Aib1,3PTH (1-14) group where definite increase of these parameters shown in the PTH (1-84) group (p < 0.001). Assessment of bone strength was evaluated with no significant differences among all groups. It was quite disappointing to see the actual discrepancies between the result of significant pharmacokinetic potency and the in vivo clinical effect of the Aib1,3PTH (1-14). However, there are several limitations to mention, such as the short duration of treatment, matter of dosage, and insufficient effect of tight -helical structures with absence of C-terminus. In conclusion, our findings suggest that unacetylated Aib1,3PTH (1-14) did not exhibit any anabolic effects at the bones of ovariectomized rats.
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Affiliation(s)
- Yumie Rhee
- Department of Internal Medicine, Endocrine Research College of Medicine, Yonsei University, Seoul, Korea
| | - Weontae Lee
- Department of Biochemistry, College of Science, Yonsei University, Seoul, Korea
| | - Eun Jin Lee
- Department of Internal Medicine, Endocrine Research College of Medicine, Yonsei University, Seoul, Korea
| | - Suhyun Ma
- Department of Biochemistry, College of Science, Yonsei University, Seoul, Korea
| | - So Young Park
- Department of Internal Medicine, Endocrine Research College of Medicine, Yonsei University, Seoul, Korea
| | - Sung-Kil Lim
- Department of Internal Medicine, Endocrine Research College of Medicine, Yonsei University, Seoul, Korea
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20
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Tyndall JDA, Pfeiffer B, Abbenante G, Fairlie DP. Over One Hundred Peptide-Activated G Protein-Coupled Receptors Recognize Ligands with Turn Structure. Chem Rev 2005; 105:793-826. [PMID: 15755077 DOI: 10.1021/cr040689g] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Joel D A Tyndall
- Center for Drug Design and Development, Institute for Molecular Bioscience, University of Queensland, Brisbane, Qld 4072, Australia
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21
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Tsomaia N, Shimizu M, Shimizu N, Gardella TJ, Mierke DF. Cooperative Interaction of Arginine-19 and the N-Terminal Signaling Domain in the Affinity and Potency of Parathyroid Hormone. Biochemistry 2004; 43:3459-70. [PMID: 15035617 DOI: 10.1021/bi036127t] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Residue 19 of parathyroid hormone (PTH) plays a unique role in the interaction process with the PTH1 receptor. A Glu(19) --> Arg(19) substitution, based on the Arg(19) of the PTH-related protein (PTHrP), increases the binding affinity when incorporated into the N-terminus of PTH [i.e., PTH(1-20)] and has no effect when introduced into the C-terminus of PTH [i.e., PTH(15-31)]. To explore Arg(19) and the midregion (residues 10-15), we designed the novel PTH scaffold peptide, PG5, which has the PTH(1-9) domain linked to the PTH(15-31) segment via a pentaglycine spacer. Substitution of Glu(19) with Arg(19) in PG5 resulted in a 9-fold increase in binding affinity. Additionally, the substitution enhanced stimulated cAMP formation in cells expressing PTH1-delNt, a PTH1 receptor construct lacking most of the N-terminus, confirming that residue 19 is interacting with the juxtamembrane portion of PTH1. The binding and signaling capacities of the PG5 analogues were diminished relative to those of PTH(1-34), indicating that the residue 10-14 region of PTH provides more than just a simple linker function. To probe this further, the structural consequences of the glycine linker and its interaction with PTH1 were examined by circular dichroism, (1)H NMR, and extensive ligand/receptor molecular dynamics simulations. The structural data clearly illustrate the helix-stabilizing effect of Arg(19) substitution propagating N-terminally from position 19 to the pentaglycine linker. Overall, these studies suggest that an alpha-helix is the preferred conformation for the residue 15-20 region of PTH and that residues 10-14 are also required for full affinity and potency of the hormone.
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Affiliation(s)
- Natia Tsomaia
- Department of Molecular Pharmacology, Division of Biology and Medicine, Brown University, Providence, Rhode Island 02912, USA
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22
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Schievano E, Mammi S, Carretta E, Fiori N, Corich M, Bisello A, Rosenblatt M, Chorev M, Peggion E. Conformational and biological characterization of human parathyroid hormone hPTH(1-34) analogues containing beta-amino acid residues in positions 17-19. Biopolymers 2004; 70:534-47. [PMID: 14648764 DOI: 10.1002/bip.10508] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The N-terminal 1-34 fragment of parathyroid hormone (PTH) elicits the full spectrum of bone-related biological activities of the intact native sequences. It has been suggested that the structural elements essential for bioactivity are two helical segments located at the N-terminal and C-terminal sequences, connected by hinges or flexible points around positions 12 and 19. In order to assess the relevance of the local conformation around Gly(18) upon biological function, we synthesized and characterized the following human (h) PTH(1-34) analogues containing beta-amino acid residues: [analogues: see text]. Biological activity and binding affinity of analogue I are one order of magnitude lower than those of the parent compound. In analogue II, both binding affinity and biological activity are partially recovered. Analogues III and V have no binding affinity and very low biological activity. Both bioactivity and binding affinity are partially recovered in analogue IV. The conformational properties of the analogues in aqueous solution containing dodecylphosphocholine micelles were studied by CD, 2D-nuclear magnetic resonance and molecular dynamics calculations. The results confirmed the presence in all analogues of two helical segments located at the N-terminal and C-terminal sequences. The insertion of beta-amino acid residues around position 18 does not cause appreciable conformational differences in the five analogues. The differences in biological activity and binding affinity among the five analogues cannot be related to structural differences in the membrane mimetic environment reported in this study. Our results stress the importance of the side-chain functionalities in the sequence 17-19 for biological function.
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Affiliation(s)
- E Schievano
- Department of Organic Chemistry, University of Padova, Institute of Biomolecular Chemistry, C.N.R, Via Marzolo 1, 35131 Padova, Italy
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23
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Abstract
Side-chain lactam bridges linking amino acid residues that are spaced several residues apart in the linear sequence offer a convenient and flexible method for introducing conformational constraints into a peptide structure. The availability of a variety of selectively cleavable protecting groups for amines and carboxylic acids allows for several approaches to the synthesis of monocyclic, dicyclic, and bicyclic lactam-bridged peptides by solid-phase methods. Multicyclic structures are also accessible, but segment-condensation syntheses with solution-phase cyclizations are most likely to provide the best synthetic approach to these more complex constrained peptides. Lactam bridges linking (i, i + 3)-, (i, i + 4), and (i, i + 7)-spaced residue pairs have all proven useful for stabilization of alpha helices, and (i, i + 3)-linked residues have also been demonstrated to stabilize beta-turns. These structures are finding an increasing number of applications in protein biology, including studies of protein folding, protein aggregation, peptide ligand-receptor recognition, and the development of more potent peptide therapeutics. Defining the functional roles of the amphiphilic alpha-helices in medium-sized peptide hormones, and studying helix propagation from rigid, alpha-helix initiating bicyclic peptides are among the most exciting developments currently underway in this field.
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Affiliation(s)
- John W Taylor
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA.
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24
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Shimizu N, Petroni BD, Khatri A, Gardella TJ. Functional evidence for an intramolecular side chain interaction between residues 6 and 10 of receptor-bound parathyroid hormone analogues. Biochemistry 2003; 42:2282-90. [PMID: 12600195 DOI: 10.1021/bi027237n] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The N-terminal domain of PTH(1-34) is critical for PTH-1 receptor (P1R) activation and has been postulated to be alpha-helical when bound to the receptor. We investigated the possibility that the side chains of residues 6 (Gln) and 10 (Gln or Asn) of PTH analogues, which would align on the same face of the predicted alpha-helix, could interact and thereby contribute to the PTH/P1R interaction process. We utilized PTH(1-11), PTH(1-14), and PTH(1-34) analogues substituted with alanine at one or both of these positions and functionally evaluated the peptides in cell lines (HKRK-B7 and HKRK-B28) stably expressing the P1R, as well as in COS-7 cells transiently expressing either the P1R or a P1R construct that lacks the amino-terminal extracellular domain (P1R-DelNt). In HKRK-B7 cells, the single substitutions of Gln(6) --> Ala and Gln(10) --> Ala reduced the cAMP-stimulating potency of [Ala(3),Gln(10),Arg(11)]rPTH(1-11)NH(2) approximately 60- and approximately 2-fold, respectively, whereas the combined Ala(6,10) substitution resulted in a approximately 2-fold gain in potency, relative to the single Ala(6) substitution. Similar effects on P1R-mediated cAMP-signaling potency and P1R-binding affinity were observed for these substitutions in [Aib(1,3),Gln(10),Har(11),Ala(12),Trp(14)]rPTH(1-14)NH(2). Installation of a lactam bridge between the Lys(6) and the Glu(10) side chains of [Ala(3,12),Lys(6),Glu(10),Har(11),Trp(14)]rPTH(1-14)NH(2) increased signaling potency 6-fold, relative to the nonbridged linear analogue. Alanine substitutions at positions 6 and/or 10 of [Tyr(34)]hPTH(1-34)NH(2) did not affect signaling potency nor binding affinity on the intact P1R; however, Ala(6) abolished PTH(1-34) signaling on P1R-DelNt, and this effect was reversed by Ala(10). The overall data support the hypothesis that the N-terminal portion of PTH is alpha-helical when bound to the activation domain of the PTH-1 receptor and they further suggest that intrahelical side chain interactions between residues 6 and 10 of the ligand can contribute to the receptor interaction process.
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Affiliation(s)
- Naoto Shimizu
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA
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25
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Piserchio A, Shimizu N, Gardella TJ, Mierke DF. Residue 19 of the parathyroid hormone: structural consequences. Biochemistry 2002; 41:13217-23. [PMID: 12403623 DOI: 10.1021/bi0261600] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Residue 19 of the parathyroid hormone (PTH) has been shown to play an important role in both binding to and activation of the PTH receptor; specifically, Arg(19)-containing analogues have improved biological function over similar Glu(19) peptides [Shimizu et al. (2002) Biochemistry 41, 13224-13233]. Additionally the juxtamembrane portion of the receptor is involved in the different biological responses. Here, we determine the conformational preferences of PTH analogues to provide a structural basis for their biological actions. On the basis of circular dichroism results, the Arg(19) --> Glu(19) mutations within the context of both PTH(1-20) and PTH(1-34) analogues lead to increases in helix content, ranging from a 8-15% increase. High-resolution structures as determined by (1)H NMR and NOE-restrained molecular dynamics simulations clearly illustrate the difference between Arg(19) and Glu(19)-PTH(1-20), particularly with the extent and stability of the C-terminal helix. The Arg(19)-containing analogue has a well defined, stable alpha-helix from Ser(4)-Arg(19), while the Glu(19) analogue is less ordered at the C-terminus. On the basis of these observations, we propose that position 19 of PTH(1-20) must be alpha-helical for optimal interaction with the juxtamembrane portion of the receptor. This mode of binding extends the current view of PTH binding (indeed ligand binding for all class B GPCRs), which invokes a bihelical ligand with the C-terminus of the ligand interacting with the N-terminus of the receptor (responsible for binding) and the N-terminus of the ligand interacting with the seven-helical bundle (leading to receptor activation).
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Affiliation(s)
- Andrea Piserchio
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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26
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Condon SM, Darnbrough S, Burns CJ, Bobko MA, Morize I, Uhl J, Jariwala NU, Burke K, Labaudiniere RF. Analogues of human parathyroid hormone (1-31)NH(2): further evaluation of the effect of conformational constraint on biological activity. Bioorg Med Chem 2002; 10:731-6. [PMID: 11814862 DOI: 10.1016/s0968-0896(01)00335-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A series of conformationally-restricted analogues of hPTH was prepared, based on the parent peptide agonist, cyclo(Lys(18)-Asp(22))[Ala(1),Nle(8),Lys(18),Asp(22),Leu(27)]hPTH(1-31)NH(2) (2, EC(50)=0.29nM). Truncation of 2 at either the N- or C-termini resulted in peptides with reduced agonist activity as measured by stimulation of adenylate cyclase activity in the rat osteosarcoma cell line (ROS 17/2.8). Alanine- and glycine-scanning at the N-terminus of 2 was consistent with data previously obtained on linear hPTH(1-34). Other locations within the primary sequence of hPTH(1-31)NH(2) were evaluated by the placement of the [i, i+4] lactam constraining element. Ring size and lactam orientations at the 18-22 positions were also examined.
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Affiliation(s)
- Stephen M Condon
- Department of Medicinal Chemistry, Rhône-Poulenc Rorer Research and Development, 500 Arcola Road, Collegeville, PA 19426, USA.
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27
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Taylor JW, Jin QK, Sbacchi M, Wang L, Belfiore P, Garnier M, Kazantzis A, Kapurniotu A, Zaratin PF, Scheideler MA. Side-chain lactam-bridge conformational constraints differentiate the activities of salmon and human calcitonins and reveal a new design concept for potent calcitonin analogues. J Med Chem 2002; 45:1108-21. [PMID: 11855991 DOI: 10.1021/jm010474o] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have recently reported the potent hypocalcemic effects of side-chain lactam-bridged analogues of human calcitonin (hCT) (Kapurniotu, A.; et al. Eur. J. Biochem. 1999, 265, 606-618). To extend these studies, we have now synthesized a new series of (Asp(17), Lys(21)) and (Asp(17), Orn(21)) side-chain bridged salmon calcitonin (sCT) and hCT analogues. The affinities of these analogues for the human calcitonin receptor, hCTR(I1)(-), and for rat-brain membrane receptors were assayed in competitive binding assays, and agonist potencies at the hCTR(I1)(-) receptors were assessed, using a cAMP-responsive gene-reporter assay. The bridged sCT analogues had activities similar to sCT itself. In contrast, an (Asp(17), Orn(21)) side-chain bridged hCT analogue, cyclo(17-21)-[Nle(8), Phe(12), Asp(17), Orn,(21) Tyr(22))-hCT, was 80 and 450 times more active than hCT in the hCTR(I1)(-) and rat-brain receptor binding assays, respectively, and was 90 times more potent than hCT and 16 times more potent than sCT in initiating receptor signaling. An uncyclized, isosteric analogue of this peptide was also more potent than hCT, demonstrating that the cyclization constraint and these single-residue substitutions enhance the activities of hCT in an additive fashion. This study demonstrates that the potency-enhancing effects of lactam-bridge constraints at hCT residues 17-21 are not transferable to sCT. We also show that, in comparison to the hCT analogues, sCT and its analogues are less potent agonists than expected from their hCTR(I1)(-) affinities. This suggests that it may be possible to preserve the efficient signal transduction of hCT while introducing additional receptor affinity-enhancing elements from sCT into our potent lactam-bridged hCT analogue, thereby creating new super-potent, hCT-based agonists.
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Affiliation(s)
- John W Taylor
- Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, New Jersey 08854, USA.
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28
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Barbier JR, MacLean S, Whitfield JF, Morley P, Willick GE. Structural requirements for conserved arginine of parathyroid hormone. Biochemistry 2001; 40:8955-61. [PMID: 11467957 DOI: 10.1021/bi010460k] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Arg-20 is one of two residues conserved in all peptides known to activate the parathyroid hormone (PTH) receptor. Previous studies have failed to find any naturally encoded analogues of residue 20 that had any adenylyl cyclase (AC) stimulating activity. In this work we have studied substitutions of Arg-20 with nonencoded amino acids and conformationally constrained analogues with side chains mimicking that of Arg. No analogue had more than 20% of the AC-stimulating ability of the natural Arg-20-bearing peptide. In descending order of activity, the most active analogues had (S)-4-piperidyl-(N-amidino)glycine (PipGly), norleucine (Nle), citrulline (Cit), or ornithine (Orn) at residue 20. Analogues with Arg-20 substituted with L-4-piperidyl-(N-amidino)alanine, Lys, Glu, Ala, Gln, (S)-2-amino-4-[(2-amino)pyrimidinyl]butanoic acid, or L-(4-guanidino)phenylalanine had very low or negligible activity. Low or negligible activities of Lys or Orn analogues suggested ionic interactions play a minor role in the Arg interaction with the receptor. The conformational constraints imposed by the PipGly ring had a negative effect on its ability to substitute for Arg. The side-chain H-bonding potential of the Cit ureimido group was likely an important factor in its mimicry of Arg. The increase in amphiphilicity, as demonstrated by its greater high-performance liquid chromatographic retention, and increased alpha-helix, as shown by circular dichroic spectroscopy, likely contributed to the activity of the Nle-20 analogue. The data demonstrated that specific H-bonding, hydrophobicity of the side chain, stabilization of alpha-helix, and possibly specific cation positioning were all important in the interaction of Arg-20 with receptor groups.
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Affiliation(s)
- J R Barbier
- Institute for Biological Sciences, National Research Council, Ottawa, Ontario, Canada K1A 0R6
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29
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Abstract
The receptor for parathyroid hormone (PTH) and PTH-related protein (PTHrP) is a G protein-coupled receptor (GPCR) that plays a key role in controlling blood Ca(2+) concentration and endochondral bone formation. This review focuses on the molecular mechanisms by which the receptor recognizes the PTH and PTHrP peptide ligands and transmits their signal across the cell membrane. The available data suggest that there are two principal components to the ligand-receptor interaction. First, a docking interaction between the C-terminal portion of PTH(1-34) and the N-terminal extracellular domain of the receptor; and second, a weaker interaction between the N-terminal portion of the ligand and the juxtamembrane region of the receptor, which induces signal transduction. A full understanding of these processes could lead to new PTH/PTHrP receptor ligands that are effective in controlling diseases of bone and mineral metabolism, such as osteoporosis.
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Affiliation(s)
- T J Gardella
- Endocrine Unit and Dept of Pediatrics, Massachusetts General Hospital and Harvard Medical School, 02114, Boston, MA, USA.
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30
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Carter PH, Gardella TJ. Zinc(II)-mediated enhancement of the agonist activity of histidine-substituted parathyroid hormone(1-14) analogues. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1538:290-304. [PMID: 11336800 DOI: 10.1016/s0167-4889(01)00080-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Previous studies on parathyroid hormone (PTH)(1-14) revealed that residues (1-9) played a dominant role in stimulating PTH-1 receptor-mediated increases in cAMP formation. In the present study, we examined the effects of installing a metal-binding motif in the (10-14) region of rat PTH(1-14) on the peptide's agonist activity. We found that substitution of histidine for the native asparagine at position 10 of PTH(1-14) provided a peptide that was approx. 8-fold more potent as an agonist in the presence of divalent zinc salts than it was in the absence of the metal. This enhancement in potency was dependent on the native histidine at position 14, the concentration of Zn(II) utilized, and did not occur with other divalent metal ions. The zinc-activated [His(10)]-PTH(1-14) peptide was blocked by a classical PTH-1 receptor antagonist, PTHrP(7-36), and did not activate the PTH-2 receptor. The zinc-mediated enhancing effect did not require the large N-terminal extracellular domain of the PTH-1 receptor. Although we were able to demonstrate that [His(10)]-PTH(1-14) binds Zn(II) using (1)H-NMR, our spectroscopic studies (circular dichroism and nuclear magnetic resonance) were not consistent with the notion that zinc enhanced the activity of [His(10)]-PTH(1-14) simply by inducing a helical structure in the 10-14 region. Rather, the data suggest that the enhancement in cAMP potency arises from the formation of a ternary complex between [His(10)]-PTH(1-14), a zinc atom, and the extracellular loop/transmembrane domain region of the PTH-1 receptor.
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Affiliation(s)
- P H Carter
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, 55 Blossom Street, Boston, MA 02114, USA
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31
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Hoare SR, Gardella TJ, Usdin TB. Evaluating the signal transduction mechanism of the parathyroid hormone 1 receptor. Effect of receptor-G-protein interaction on the ligand binding mechanism and receptor conformation. J Biol Chem 2001; 276:7741-53. [PMID: 11108715 DOI: 10.1074/jbc.m009395200] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ligand binding to the PTH1 receptor is described by a "two-site" model, in which the C-terminal portion of the ligand interacts with the N-terminal domain of the receptor (N interaction), and the N-terminal region of the ligand binds the juxtamembrane domain of the receptor (J interaction). Previous studies have not considered the dynamic nature of receptor conformation in ligand binding and receptor activation. In this study the ligand binding mechanism was compared for the G-protein-coupled (RG) and uncoupled (R) PTH1 receptor conformations. The two-site model was confirmed by demonstration of spatially distinct binding sites for PTH(3-34) and PTH(1-14): PTH(1-14), which binds predominantly to the J domain, only partially inhibited binding of 125I-PTH(3-34); and PTH(3-34), shown to bind predominantly to the N domain, only partially inhibited PTH(1-14)-stimulated cAMP accumulation. To assess the effect of R-G coupling, ligand binding to R was measured by displacement of 125I-PTH(3-34) with 30 microM guanosine 5'-3-O-(thio)triphosphate (GTPgammaS) present, and binding to RG was measured by displacement of 125I-[MAP]PTHrP(1-36) (where MAP is model amphipathic peptide), a new radioligand that binds selectively to RG. Agonists bound with higher affinity to RG than R, whereas antagonists bound similarly to these states. The J interaction was responsible for enhanced agonist binding to RG: residues 1 and 2 were required for increased PTH(1-34) affinity for RG; residue 5 of MAP-PTHrP(1-36) was a determinant of R/RG binding selectivity, and PTH(1-14) bound selectively to RG. The N interaction was insensitive to R-G coupling; PTH(3-34) binding was GTPgammaS-insensitive. Finally, several observations suggest the receptor conformation is more "closed" at RG than R. At the R state, an open conformation is suggested by the simultaneous binding of PTH(1-14) and PTH(3-34). At RG PTH(1-14) better occluded binding of 125I-PTH(3-34) and agonist ligands bound pseudo-irreversibly, suggesting a more closed conformation of this receptor state. The results extend the two-site model to take into account R and RG conformations and suggest a model for differences of receptor conformation between these states.
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Affiliation(s)
- S R Hoare
- Unit on Cell Biology, Laboratory of Genetics, National Institute of Mental Health, Bethesda, Maryland 20892-4092, USA
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Morley P, Whitfield JF, Willick GE, Ross V, MacLean S, Barbier JR, Isaacs RJ, Andreassen TT. The effect of monocyclic and bicyclic analogs of human parathyroid hormone (hPTH)-(1-31)NH2 on bone formation and mechanical strength in ovariectomized rats. Calcif Tissue Int 2001; 68:95-101. [PMID: 11310353 DOI: 10.1007/bf02678147] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The [Leu27]cyclo(Glu22-Lys26)-hPTH-(1-31)NH2 lactam is a stronger stimulator of adenylyl cyclase activity and a better stimulator of trabecular bone in the ovariectomized (OVX) rat model of osteopenia than hPTH-(1-31)NH2. This enhanced activity is due in large part to the stabilization of the amphiphilic receptor-binding alpha-helix in the Ser17-Gln29 region. The goal of the present study was to determine whether further cyclization could produce a more active hPTH analog. To this end, we compared the relative bioactivities of the bicyclic hPTH analog [Glu17,Leu27]cyclo(Lys13-Glu17,Glu22-Lys26)-hPTH-(1-31)NH2, made by replacing Ser17 with Glu17 and introducing a second lactam linkage between Lys13 and Glu17. The relative EC50 for adenylyl cyclase stimulation by the bicyclic hPTH analog was similar to the EC50 of the monocyclic [Leu27]cyclo(Glu22-Lys26)-hPTH-(1-31)NH2, but the bicyclic analog was still more active than hPTH-(1-31)NH2. As expected from adenylyl cyclase stimulation being responsible for PTH's anabolic action, the bicyclic hPTH analog [Glu17, Leu27]cyclo(Lys13-Glu17, Glu22-Lys26)-hPTH-(1-31)NH2 was able to increase femoral trabecular volume and thickness and mechanical strength in OVX rats, but it was no more effective than [Leu27]cyclo(Glu22-Lys26)-hPTH-(1-31)NH2 when injected once daily in a dose of 0.8 nmol/100 g body weight. Thus, further constraint of the conformation of hPTH-(1-31)NH2 by introducing two lactam link-ages between Lys13-Glu17 and Glu22-Lys26 did not raise the osteogenicity above that of the monocyclic analog.
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Affiliation(s)
- P Morley
- Institute for Biological Sciences, National Research Council of Canada, Montreal Road Campus, Building M-54, Ottawa, Ontario, Canada K1A 0R6
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Barbier JR, MacLean S, Morley P, Whitfield JF, Willick GE. Structure and activities of constrained analogues of human parathyroid hormone and parathyroid hormone-related peptide: implications for receptor-activating conformations of the hormones. Biochemistry 2000; 39:14522-30. [PMID: 11087406 DOI: 10.1021/bi001527r] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Parathyroid hormone (PTH) has a helix-bend-helix structure in solution. Part of the C-terminal helix, residues 21-31, is amphiphilic and forms a critical receptor-binding region. Stabilization of this alpha-helix by lactam formation between residues spaced i, i + 4 on the polar face was previously reported to increase adenylyl cyclase-stimulating (AC) activity if between residues 22 and 26 but to diminish it if between residues 26 and 30 [Barbier et al. (1997) J. Med. Chem. 40, 1373-1380]. This work reports the effects of other cyclizations on the polar face, differing in ring size or position, on alpha-helix conformation, as measured by circular dichroism, and on AC-stimulating activity. All analogues cyclized between residues 22 and 26 had at least a 1. 5-fold increase in activity, suggesting an alpha-helical structure between about residues 21 and 26. Cyclization between residues 25 and 29 or residues 26 and 30 diminished activity by 20-30%, despite stabilizing alpha-helix, suggesting that residues 25-31 bind to the receptor in a helical, but not classical alpha-helical, conformation. Analogues cyclized between residues 13 and 17 had slightly increased activity. A bicyclic analogue, with lactams between residues 13 and 17 and residues 22 and 26, had about the same activity as that cyclized only between 22 and 26. Parathyroid hormone-related peptide (PTHrP) may bind in a manner similar to the common receptor, but hydrophobic moment calculations suggest that it must bind as a tighter helix in order to optimally present its hydrophobic residues to the receptor. Both PTHrP analogues cyclized between either residues 22 and 26 or residues 26 and 30 had more stable alpha-helices but reduced AC activities, consistent with this hypothesis.
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Affiliation(s)
- J R Barbier
- Institute for Biological Sciences, National Research Council, Ottawa, Ontario, Canada K1A 0R6
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Chen Z, Xu P, Barbier JR, Willick G, Ni F. Solution structure of the osteogenic 1-31 fragment of the human parathyroid hormone. Biochemistry 2000; 39:12766-77. [PMID: 11041841 DOI: 10.1021/bi000882e] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The solution conformations of a selectively osteogenic 1-31 fragment of the human parathyroid hormone (hPTH), hPTH(1-31)NH(2), have been characterized by use of very high field NMR spectroscopy at 800 MHz. The combination of the CalphaH proton and (13)Calpha chemical shifts, (3)J(NH)(alpha) coupling constants, NH proton temperature coefficients, and backbone NOEs reveals that the hPTH(1-31)NH(2) peptide has well-formed helical structures localized in two distinct segments of the polypeptide backbone. There are also many characteristic NOEs defining specific side-chain/backbone and side-chain/side-chain contacts within both helical structures. The solution structure of hPTH(1-31)NH(2) contains a short N-terminal helical segment for residues 3-11, including the helix capping residues 3 and 11 and a long C-terminal helix for residues 16-30. The two helical structures are reinforced by well-defined capping motifs and side-chain packing interactions within and at both ends of these helices. On one face of the C-terminal helix, there are side-chain pairs of Glu22-Arg25, Glu22-Lys26, and Arg25-Gln29 that can form ion-pair and/or hydrogen bonding interactions. On the opposite face of this helix, there are characteristic hydrophobic interactions involving the aromatic side chain of Trp23 packing against the aliphatic side chains of Leu15, Leu24, Lys27, and Leu28. There is also a linear array of hydrophobic residues from Val2, to Leu7, to Leu11 and continuing on to residues His14 and Leu15 in the hinge region and to Trp23 in the C-terminal helix. Capping and hydrophobic interactions at the end of the N-terminal and at the beginning of the C-terminal helix appear to consolidate the helical structures into a V-shaped overall conformation for at least the folded population of the hPTH(1-31)NH(2) peptide. Stabilization of well-folded conformations in this linear 1-31 peptide fragment and possibly other analogues of human PTH may have a significant impact on the biological activities of the PTH peptides in general and specifically for the osteogenic/anabolic activities of bone-building PTH analogues.
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Affiliation(s)
- Z Chen
- Biomolecular NMR Laboratory and the Montréal Joint Centre for Structural Biology, Biotechnology Research Institute, National Research Council of Canada, Montréal, Québec, Canada
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Jin L, Briggs SL, Chandrasekhar S, Chirgadze NY, Clawson DK, Schevitz RW, Smiley DL, Tashjian AH, Zhang F. Crystal Structure of Human Parathyroid Hormone 1–34 at 0.9-Å Resolution. J Biol Chem 2000. [DOI: 10.1016/s0021-9258(19)61502-4] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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