1
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Cook Sangar ML, Girard EJ, Hopping G, Yin C, Pakiam F, Brusniak MY, Nguyen E, Ruff R, Gewe MM, Byrnes-Blake K, Nairn NW, Miller DM, Mehlin C, Strand AD, Mhyre AJ, Correnti CE, Strong RK, Simon JA, Olson JM. A potent peptide-steroid conjugate accumulates in cartilage and reverses arthritis without evidence of systemic corticosteroid exposure. Sci Transl Med 2021; 12:12/533/eaay1041. [PMID: 32132215 DOI: 10.1126/scitranslmed.aay1041] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 01/23/2020] [Indexed: 12/12/2022]
Abstract
On-target, off-tissue toxicity limits the systemic use of drugs that would otherwise reduce symptoms or reverse the damage of arthritic diseases, leaving millions of patients in pain and with limited physical mobility. We identified cystine-dense peptides (CDPs) that rapidly accumulate in cartilage of the knees, ankles, hips, shoulders, and intervertebral discs after systemic administration. These CDPs could be used to concentrate arthritis drugs in joints. A cartilage-accumulating peptide, CDP-11R, reached peak concentration in cartilage within 30 min after administration and remained detectable for more than 4 days. Structural analysis of the peptides by crystallography revealed that the distribution of positive charge may be a distinguishing feature of joint-accumulating CDPs. In addition, quantitative whole-body autoradiography showed that the disulfide-bonded tertiary structure is critical for cartilage accumulation and retention. CDP-11R distributed to joints while carrying a fluorophore imaging agent or one of two different steroid payloads, dexamethasone (dex) and triamcinolone acetonide (TAA). Of the two payloads, the dex conjugate did not advance because the free drug released into circulation was sufficient to cause on-target toxicity. In contrast, the CDP-11R-TAA conjugate alleviated joint inflammation in the rat collagen-induced model of rheumatoid arthritis while avoiding toxicities that occurred with nontargeted steroid treatment at the same molar dose. This conjugate shows promise for clinical development and establishes proof of concept for multijoint targeting of disease-modifying therapeutic payloads.
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Affiliation(s)
- Michelle L Cook Sangar
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Emily J Girard
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Gene Hopping
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Chunfeng Yin
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Fiona Pakiam
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Mi-Youn Brusniak
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Elizabeth Nguyen
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Raymond Ruff
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Mesfin M Gewe
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.,Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | | | | | | | - Christopher Mehlin
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Andrew D Strand
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Andrew J Mhyre
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Colin E Correnti
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Roland K Strong
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Julian A Simon
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.,Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - James M Olson
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
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2
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Crook ZR, Girard E, Sevilla GP, Merrill M, Friend D, Rupert PB, Pakiam F, Nguyen E, Yin C, Ruff RO, Hopping G, Strand AD, Finton KAK, Coxon M, Mhyre AJ, Strong RK, Olson JM. A TfR-Binding Cystine-Dense Peptide Promotes Blood-Brain Barrier Penetration of Bioactive Molecules. J Mol Biol 2020; 432:3989-4009. [PMID: 32304700 DOI: 10.1016/j.jmb.2020.04.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 04/01/2020] [Accepted: 04/06/2020] [Indexed: 02/06/2023]
Abstract
The impenetrability of the blood-brain barrier (BBB) to most conventional drugs impedes the treatment of central nervous system (CNS) disorders. Interventions for diseases like brain cancer, neurodegeneration, or age-associated inflammatory processes require varied approaches to CNS drug delivery. Cystine-dense peptides (CDPs) have drawn recent interest as drugs or drug-delivery vehicles. Found throughout the phylogenetic tree, often in drug-like roles, their size, stability, and protein interaction capabilities make CDPs an attractive mid-size biologic scaffold to complement conventional antibody-based drugs. Here, we describe the identification, maturation, characterization, and utilization of a CDP that binds to the transferrin receptor (TfR), a native receptor and BBB transporter for the iron chaperone transferrin. We developed variants with varying binding affinities (KD as low as 216 pM), co-crystallized it with the receptor, and confirmed murine cross-reactivity. It accumulates in the mouse CNS at ~25% of blood levels (CNS blood content is only ~1%-6%) and delivers neurotensin, an otherwise non-BBB-penetrant neuropeptide, at levels capable of modulating CREB signaling in the mouse brain. Our work highlights the utility of CDPs as a diverse, easy-to-screen scaffold family worthy of inclusion in modern drug discovery strategies, demonstrated by the discovery of a candidate CNS drug delivery vehicle ready for further optimization and preclinical development.
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Affiliation(s)
- Zachary R Crook
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Emily Girard
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Gregory P Sevilla
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Morgan Merrill
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Della Friend
- Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Peter B Rupert
- Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Fiona Pakiam
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Elizabeth Nguyen
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Chunfeng Yin
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Raymond O Ruff
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Gene Hopping
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Andrew D Strand
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Kathryn A K Finton
- Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Margo Coxon
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Andrew J Mhyre
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - Roland K Strong
- Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA
| | - James M Olson
- Clinical Research Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA 98109, USA.
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3
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Sottero TL, Girard EJ, Myers C, Hopping G, Mhyre AJ, Olson JM. Pacifastin-derived Peptides Target Tumors for Use in In Vivo Imaging. Anticancer Res 2017; 38:51-60. [PMID: 29277756 DOI: 10.21873/anticanres.12191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 11/17/2017] [Accepted: 11/20/2017] [Indexed: 11/10/2022]
Abstract
BACKGROUND/AIM Developments in imaging have improved cancer diagnosis, but identification of malignant cells during surgical resection remains a challenge. The aim of this study was to investigate the pacifastin family of peptides for novel activity targeting tumor cells and the delivery of either imaging or therapeutic agents. MATERIALS AND METHODS Variants of pacifastin family peptides were generated, chemically modified and tested in human tumor xenografts. RESULTS A tumor-homing peptide-dye conjugate (THP1) accumulated in tumors in vivo and was internalized into cells. Examination of related peptides revealed residues critical for accumulation and allowed the engineering of improved tumor-targeting variants. A THP1-drug conjugate carrying the microtubule inhibitor, MMAE, showed limited activity in vitro and no difference compared to vehicle control in vivo. CONCLUSION Although there are some obstacles to developing pacifastin-derived peptides for therapeutic activity, these optimized peptides have great promise for cancer imaging.
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Affiliation(s)
- Theo L Sottero
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, U.S.A.,Department of Pharmacology, University of Washington, Seattle, WA, U.S.A
| | - Emily J Girard
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, U.S.A
| | - Carrie Myers
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, U.S.A
| | - Gene Hopping
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, U.S.A
| | - Andrew J Mhyre
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, U.S.A
| | - James M Olson
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, U.S.A.
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4
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Towse CL, Hopping G, Vulovic I, Daggett V. Nature versus design: the conformational propensities of D-amino acids and the importance of side chain chirality. Protein Eng Des Sel 2014; 27:447-55. [PMID: 25233851 PMCID: PMC4204638 DOI: 10.1093/protein/gzu037] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 08/04/2014] [Accepted: 08/11/2014] [Indexed: 11/12/2022] Open
Abstract
D-amino acids are useful building blocks for de novo peptide design and they play a role in aging-related diseases associated with gradual protein racemization. For amino acids with achiral side chains, one should be able to presume that the conformational propensities of L- and D-amino acids are a reflection of one another due to the straightforward geometric inversion at the Cα atom. However, this presumption does not account for the directionality of the backbone dipole and the inverted propensities have never been definitively confirmed in this context. Furthermore, there is little known of how alternative side chain chirality affects the backbone conformations of isoleucine and threonine. Using a GGXGG host-guest pentapeptide system, we have completed exhaustive sampling of the conformational propensities of the D-amino acids, including D-allo-isoleucine and D-allo-threonine, using atomistic molecular dynamics simulations. Comparison of these simulations with the same systems hosting the cognate L-amino acids verifies that the intrinsic backbone conformational propensities of the D-amino acids are the inverse of their cognate L-enantiomers. Where amino acids have a chiral center in their side chain (Thr, Ile) the β-configuration affects the backbone sampling, which in turn can confer different biological properties.
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Affiliation(s)
- Clare-Louise Towse
- Department of Bioengineering, University of Washington, Seattle, WA 98195-5013, USA
| | - Gene Hopping
- Department of Bioengineering, University of Washington, Seattle, WA 98195-5013, USA
| | - Ivan Vulovic
- Department of Bioengineering, University of Washington, Seattle, WA 98195-5013, USA
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, WA 98195-5013, USA
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Hopping G, Wang CIA, Hogg RC, Nevin ST, Lewis RJ, Adams DJ, Alewood PF. Hydrophobic residues at position 10 of α-conotoxin PnIA influence subtype selectivity between α7 and α3β2 neuronal nicotinic acetylcholine receptors. Biochem Pharmacol 2014; 91:534-42. [PMID: 25101833 DOI: 10.1016/j.bcp.2014.07.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 07/25/2014] [Accepted: 07/28/2014] [Indexed: 11/25/2022]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) are a diverse class of ligand-gated ion channels involved in neurological conditions such as neuropathic pain and Alzheimer's disease. α-Conotoxin [A10L]PnIA is a potent and selective antagonist of the mammalian α7 nAChR with a key binding interaction at position 10. We now describe a molecular analysis of the receptor-ligand interactions that determine the role of position 10 in determining potency and selectivity for the α7 and α3β2 nAChR subtypes. Using electrophysiological and radioligand binding methods on a suite of [A10L]PnIA analogs we observed that hydrophobic residues in position 10 maintained potency at both subtypes whereas charged or polar residues abolished α7 binding. Molecular docking revealed dominant hydrophobic interactions with several α7 and α3β2 receptor residues via a hydrophobic funnel. Incorporation of norleucine (Nle) caused the largest (8-fold) increase in affinity for the α7 subtype (Ki=44nM) though selectivity reverted to α3β2 (IC50=0.7nM). It appears that the placement of a single methyl group determines selectivity between α7 and α3β2 nAChRs via different molecular determinants.
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Affiliation(s)
- Gene Hopping
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - C-I Anderson Wang
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Ron C Hogg
- Department of Neuroscience, Centre Medical Universitaire, Medical Faculty, 1 rue Michel Servet, CH-1211 Geneva 4, Switzerland
| | - Simon T Nevin
- Queensland Brain Institute, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - David J Adams
- Queensland Brain Institute, The University of Queensland, St. Lucia, Queensland 4072, Australia; Health Innovations Research Institute, RMIT University, Bundoora, Victoria 3083, Australia
| | - Paul F Alewood
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia.
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6
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Hopping G, Kellock J, Barnwal RP, Law P, Bryers J, Varani G, Caughey B, Daggett V. Designed α-sheet peptides inhibit amyloid formation by targeting toxic oligomers. eLife 2014; 3:e01681. [PMID: 25027691 PMCID: PMC4091096 DOI: 10.7554/elife.01681] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Previous studies suggest that the toxic soluble-oligomeric form of different amyloid proteins share a common backbone conformation, but the amorphous nature of this oligomer prevents its structural characterization by experiment. Based on molecular dynamics simulations we proposed that toxic intermediates of different amyloid proteins adopt a common, nonstandard secondary structure, called α-sheet. Here we report the experimental characterization of peptides designed to be complementary to the α-sheet conformation observed in the simulations. We demonstrate inhibition of aggregation in two different amyloid systems, β-amyloid peptide (Aβ) and transthyretin, by these designed α-sheet peptides. When immobilized the α-sheet designs preferentially bind species from solutions enriched in the toxic conformer compared with non-aggregated, nontoxic species or mature fibrils. The designs display characteristic spectroscopic signatures distinguishing them from conventional secondary structures, supporting α-sheet as a structure involved in the toxic oligomer stage of amyloid formation and paving the way for novel therapeutics and diagnostics. DOI:http://dx.doi.org/10.7554/eLife.01681.001 The build up of very thin fibres called amyloid fibrils is known to lead to more than 40 different human diseases, including Parkinson’s disease and rheumatoid arthritis. These diseases involve soluble proteins or peptides joining other proteins or peptides to form the fibrils, which are not soluble. However, the damage is done by the time the fibrils form because soluble intermediate structures formed by the proteins and peptides are toxic. The development of methods that can detect these toxic intermediate structures could lead to earlier interventions before significant damage. Amyloid fibrils are known to have a beta-sheet structure that is found in many protein systems. In 2004, based on computer simulations, researchers predicted that proteins and peptides that go on to form amyloid fibrils would pass through a related but less stable structure called an alpha-sheet, and that this structure would be toxic. Now Hopping et al., including some of the researchers involved in the 2004 work, have confirmed that the alpha-sheet structure is indeed involved in the formation of amyloid fibrils. To do this Hopping et al. designed peptides with alpha-sheet structures that could bind to the alpha-sheet structures predicted by their simulations. When these complementary designed peptides were added to a solution of peptide that causes Alzheimer’s Disease, or a protein that causes systemic amyloid disease, the designed peptides bound the toxic peptides or proteins and prevented the formation of fibrils. The results of Hopping et al. suggest that designed alpha-sheet compounds might be able to capture peptides and proteins that are implicated in a wide variety of amyloid diseases, independent of their composition and native structure, by targeting the intermediate alpha-sheet structure. Future challenges include showing that most proteins and peptides pass through this intermediate structure as they form fibrils, and improving the sensitivity of the binding in the hope of developing diagnostics for amyloid diseases. DOI:http://dx.doi.org/10.7554/eLife.01681.002
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Affiliation(s)
- Gene Hopping
- Department of Bioengineering, University of Washington, Seattle, United States
| | - Jackson Kellock
- Department of Bioengineering, University of Washington, Seattle, United States
| | | | - Peter Law
- Department of Bioengineering, University of Washington, Seattle, United States
| | - James Bryers
- Department of Bioengineering, University of Washington, Seattle, United States
| | - Gabriele Varani
- Department of Chemistry, University of Washington, Seattle, United States
| | - Byron Caughey
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, United States
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, United States
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7
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Hopping G, Kellock J, Caughey B, Daggett V. Designed Trpzip-3 β-Hairpin Inhibits Amyloid Formation in Two Different Amyloid Systems. ACS Med Chem Lett 2013; 4:824-8. [PMID: 24900756 DOI: 10.1021/ml300478w] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Accepted: 08/01/2013] [Indexed: 11/29/2022] Open
Abstract
The trpzip peptides are small, monomeric, and extremely stable β-hairpins that have become valuable tools for studying protein folding. Here, we show that trpzip-3 inhibits aggregation in two very different amyloid systems: transthyretin and Aβ(1-42). Interestingly, Trp → Leu mutations renders the peptide ineffective against transthyretin, but Aβ inhibition remains. Computational docking was used to predict the interactions between trpzip-3 and transthyretin, suggesting that inhibition occurs via binding to the outer region of the thyroxine-binding site, which is supported by dye displacement experiments.
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Affiliation(s)
- Gene Hopping
- Department of Bioengineering, University of Washington, Seattle, Washington 98195,
United States
| | - Jackson Kellock
- Department of Bioengineering, University of Washington, Seattle, Washington 98195,
United States
| | - Byron Caughey
- Laboratory
of Persistent Viral
Diseases, Rocky Mountain Laboratories, National Institute of Allergy
and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, United States
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, Washington 98195,
United States
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8
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de Araujo AD, Callaghan B, Nevin ST, Daly NL, Craik DJ, Moretta M, Hopping G, Christie MJ, Adams DJ, Alewood PF. Total Synthesis of the Analgesic Conotoxin MrVIB through Selenocysteine-Assisted Folding. Angew Chem Int Ed Engl 2011; 50:6527-9. [DOI: 10.1002/anie.201101642] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Indexed: 12/30/2022]
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9
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de Araujo AD, Callaghan B, Nevin ST, Daly NL, Craik DJ, Moretta M, Hopping G, Christie MJ, Adams DJ, Alewood PF. Total Synthesis of the Analgesic Conotoxin MrVIB through Selenocysteine-Assisted Folding. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201101642] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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10
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Alewood D, Hopping G, Brust A, Reid RC, Alewood PF. Benzhydrylamine linker grafting: a strategy for the improved synthesis of C
-terminal peptide amides. J Pept Sci 2010; 16:551-7. [DOI: 10.1002/psc.1248] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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11
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Abstract
Grafting different regions of related peptides together to form a single protein chimera is a valuable tool in rapidly elucidating regions of activity or selectivity in peptides and proteins. To conveniently evaluate the contributions of the N- and C-terminal segments of ω-conotoxins CVID and MVIIC to activity, we employed native chemical ligation in CVID-MVIIC chimera design. Assembly of these peptide segments via the ligation method improved overall yield and coupling efficiency, with no difficult sequences encountered in contrast to the traditional full-length chain assembly of CVID. Radio-ligand binding assays revealed regions of importance for receptor recognition.
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12
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Dutertre S, Ulens C, Büttner R, Fish A, van Elk R, Kendel Y, Hopping G, Alewood PF, Schroeder C, Nicke A, Smit AB, Sixma TK, Lewis RJ. AChBP-targeted alpha-conotoxin correlates distinct binding orientations with nAChR subtype selectivity. EMBO J 2007; 26:3858-67. [PMID: 17660751 PMCID: PMC1952216 DOI: 10.1038/sj.emboj.7601785] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Accepted: 06/12/2007] [Indexed: 11/09/2022] Open
Abstract
Neuronal nAChRs are a diverse family of pentameric ion channels with wide distribution throughout cells of the nervous and immune systems. However, the role of specific subtypes in normal and pathological states remains poorly understood due to the lack of selective probes. Here, we used a binding assay based on acetylcholine-binding protein (AChBP), a homolog of the nicotinic acetylcholine ligand-binding domain, to discover a novel alpha-conotoxin (alpha-TxIA) in the venom of Conus textile. Alpha-TxIA bound with high affinity to AChBPs from different species and selectively targeted the alpha(3)beta(2) nAChR subtype. A co-crystal structure of Ac-AChBP with the enhanced potency analog TxIA(A10L), revealed a 20 degrees backbone tilt compared to other AChBP-conotoxin complexes. This reorientation was coordinated by a key salt bridge formed between Arg5 (TxIA) and Asp195 (Ac-AChBP). Mutagenesis studies, biochemical assays and electrophysiological recordings directly correlated the interactions observed in the co-crystal structure to binding affinity at AChBP and different nAChR subtypes. Together, these results establish a new pharmacophore for the design of novel subtype-selective ligands with therapeutic potential in nAChR-related diseases.
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Affiliation(s)
- Sébastien Dutertre
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Chris Ulens
- Division of Molecular Carcinogenesis and Center for Biomedical Genetics, Netherlands Cancer Institute, Plesmanlaan, CX Amsterdam, The Netherlands
| | - Regina Büttner
- Department of Neurochemistry, Max Planck Institute for Brain Research, Deutschordenstrasse 46, Frankfurt am Main, Germany
| | - Alexander Fish
- Division of Molecular Carcinogenesis and Center for Biomedical Genetics, Netherlands Cancer Institute, Plesmanlaan, CX Amsterdam, The Netherlands
| | - René van Elk
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, The Netherlands
| | - Yvonne Kendel
- Zentrum der Rechtsmedizin, University of Frankfurt, Frankfurt am Main, Germany
| | - Gene Hopping
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Paul F Alewood
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Christina Schroeder
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Annette Nicke
- Department of Neurochemistry, Max Planck Institute for Brain Research, Deutschordenstrasse 46, Frankfurt am Main, Germany
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit, Amsterdam, The Netherlands
| | - Titia K Sixma
- Division of Molecular Carcinogenesis and Center for Biomedical Genetics, Netherlands Cancer Institute, Plesmanlaan, CX Amsterdam, The Netherlands
- Division of Molecular Carcinogenesis and Center for Biomedical Genetics, Netherlands Cancer Institute, Plesmanlaan, 1066 CX Amsterdam, The Netherlands. E-mail:
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
- Institute for Molecular Bioscience, The University of Queensland, Carmodty Rd, Brisbane, Queensland 4072, Australia. Tel.: +617 3346 2984; Fax: +617 3346 2101; E-mail:
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13
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Hogg RC, Hopping G, Alewood PF, Adams DJ, Bertrand D. Alpha-conotoxins PnIA and [A10L]PnIA stabilize different states of the alpha7-L247T nicotinic acetylcholine receptor. J Biol Chem 2003; 278:26908-14. [PMID: 12746432 DOI: 10.1074/jbc.m212628200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The effects of the native alpha-conotoxin PnIA, its synthetic derivative [A10L]PnIA and alanine scan derivatives of [A10L]PnIA were investigated on chick wild type alpha7 and alpha7-L247T mutant nicotinic acetylcholine receptors (nAChRs) expressed in Xenopus oocytes. PnIA and [A10L]PnIA inhibited acetylcholine (ACh)-activated currents at wtalpha7 receptors with IC50 values of 349 and 168 nm, respectively. Rates of onset of inhibition were similar for PnIA and [A10L]PnIA; however, the rate of recovery was slower for [A10L]PnIA, indicating that the increased potency of [A10L]PnIA at alpha7 receptors is conveyed by its slower rate of dissociation from the receptors. All the alanine mutants of [A10L]PnIA inhibited ACh-activated currents at wtalpha7 receptors. Insertion of an alanine residue between position 5 and 13 and at position 15 significantly reduced the ability of [A10L]PnIA to inhibit ACh-evoked currents. PnIA inhibited the non-desensitizing ACh-activated currents at alpha7-L247T receptors with an IC50 194 nm. In contrast, [A10L]PnIA and the alanine mutants potentiated the ACh-activated current alpha7-L247T receptors and in addition [A10L]PnIA acted as an agonist. PnIA stabilized the receptor in a state that is non-conducting in both the wild type and mutant receptors, whereas [A10L]PnIA stabilized a state that is non-conducting in the wild type receptor and conducting in the alpha7-L247T mutant. These data indicate that the change of a single amino acid side-chain, at position 10, is sufficient to change the toxin specificity for receptor states in the alpha7-L247T mutant.
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Affiliation(s)
- Ron C Hogg
- Department of Physiology, CMU, 1 rue Michel Servet, CH-1211 Geneva 4, Switzerland.
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