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Kuntsche J, Rajakulendran K, Sabriye HMT, Tawakal N, Khandelia H, Hakami Zanjani AA. Drastic differences between the release kinetics of two highly related porphyrins in liposomal membranes: mTHPP and pTHPP. J Colloid Interface Sci 2023; 651:750-759. [PMID: 37572612 DOI: 10.1016/j.jcis.2023.07.152] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 07/14/2023] [Accepted: 07/24/2023] [Indexed: 08/14/2023]
Abstract
HYPOTHESIS The release of hydrophobic compounds from liposomal membranes occurs by partitioning and is thus determined by the physicochemical properties (e.g. logP and water solubility) of the drug. We postulate that even minor structural differences, e.g. the position of the phenolic OH-group of the hydrophobic porphyrins mTHPP and pTHPP (meta vs. para substitution), distinctly affect their partitioning and release behavior from liposomes. EXPERIMENTS The release and redistribution of mTHPP and pTHPP from lecithin or POPC/POPG liposomes to different acceptor particles (DSPE-mPEG micelles and liposomes) was studied by asymmetrical flow field-flow fractionation to separate donor and acceptor particles. Reversed phase HPLC was applied to detect differences in partitioning. Molecular dynamics (MD) simulations were carried out to obtain molecular insight in the different behavior of the two compounds inside a lipid bilayer. FINDINGS Despite the minor differences in chemical structure, mTHPP is more hydrophobic and redistributes much slower to both acceptor phases than pTHPP. MD simulations indicate that compared to pTHPP, mTHPP makes stronger hydrogen bonds with the lipid head groups, is oriented more parallel to the lipid tails and is embedded slightly deeper in the membrane.
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Affiliation(s)
- Judith Kuntsche
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark.
| | - Kirishana Rajakulendran
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
| | - Hibo Mohamed Takane Sabriye
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
| | - Navidullah Tawakal
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
| | - Himanshu Khandelia
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
| | - Ali Asghar Hakami Zanjani
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark.
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Hakami Zanjani AA, Nguyen TQT, Jacobsen L, Khandelia H. The molecular basis of the antidepressant action of the magic mushroom extract, psilocin. Biochim Biophys Acta Proteins Proteom 2023; 1871:140914. [PMID: 37019325 DOI: 10.1016/j.bbapap.2023.140914] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 03/27/2023] [Accepted: 03/28/2023] [Indexed: 04/05/2023]
Abstract
Magic mushrooms, and their extract psilocybin, are well-known for their psychedelic properties and recreational use. Psilocin, the bio-active form of psilocybin, can potentially treat various psychiatric diseases. Psilocin putatively exerts its psychedelic effect as an agonist to the serotonin 2A receptor (5-HT2AR), which is also the receptor for the neurological hormone serotonin. The two key chemical differences between the two molecules are first, that the primary amine in serotonin is replaced with a tertiary amine in psilocin, and second, the hydroxyl group is substituted differently on the aromatic ring. Here, we find that psilocin can bind to 5-HT2AR with an affinity higher than serotonin, and provide the molecular logic behind the higher binding affinity of psilocin using extensive molecular dynamics simulations and free energy calculations. The binding free energy of psilocin is dependent upon the protonation states of the ligands, as well as that of the key residue in the binding site: Aspartate 155. We find that the tertiary amine of psilocin, and not the altered substitution of the hydroxyl group in the ring is responsible for the increased affinity of psilocin. We propose design rules for effective antidepressants based on molecular insights from our simulations.
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Affiliation(s)
- Ali Asghar Hakami Zanjani
- PHYLIFE, Physical Life Science, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense 5230, Denmark.
| | - Teresa Quynh Tram Nguyen
- PHYLIFE, Physical Life Science, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense 5230, Denmark
| | - Luise Jacobsen
- PHYLIFE, Physical Life Science, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense 5230, Denmark
| | - Himanshu Khandelia
- PHYLIFE, Physical Life Science, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense 5230, Denmark.
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Zanjani AAH, Mularski A, Heitmann ASB, Dias C, Møller ME, Kenji M, Nylandsted J, Simonsen AC, Khandelia H. Engineering a Membrane-binding Protein to Trimerize and Induce High Membrane Curvature. Biophys J 2023:S0006-3495(23)00232-1. [PMID: 37029488 PMCID: PMC10398344 DOI: 10.1016/j.bpj.2023.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/21/2023] [Accepted: 04/03/2023] [Indexed: 04/08/2023] Open
Abstract
The annexins are a family of Ca2+-dependent peripheral membrane proteins. Several annexins are implicated in plasma membrane repair and are overexpressed in cancer cells. Annexin A4 (ANXA4) and Annexin A5 (ANXA5) form trimers that induce high curvature on a membrane surface, a phenomenon deemed to accelerate membrane repair. Despite being highly homologous to ANXA4, Annexin A3 (ANXA3) does not form trimers on the membrane surface. Using molecular dynamics (MD) simulations, we have reverse-engineered an ANXA3-mutant (ANXA3-MUT) to trimerize on the surface of the membrane and induce high curvature reminiscent of ANXA4. In addition, AFM images show that like ANXA4, the engineered protein forms crystalline arrays on a supported lipid membrane. In spite of the trimer-forming and curvature-inducing properties of the engineered ANXA3, it does not accumulate near a membrane lesion in laser-punctured cells and is unable to repair the lesion. Our investigation provides insights into the factors which drive annexin-mediated membrane repair and shows that the membrane repairing property of trimer-forming annexins also necessitates high membrane binding affinity, other than trimer formation and induction of negative membrane curvature.
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Zohairi F, Khandelia H, Hakami Zanjani AA. Interaction of psychedelic tryptamine derivatives with a lipid bilayer. Chem Phys Lipids 2023; 251:105279. [PMID: 36627076 DOI: 10.1016/j.chemphyslip.2023.105279] [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: 11/16/2022] [Revised: 01/04/2023] [Accepted: 01/05/2023] [Indexed: 01/09/2023]
Abstract
Naturally occurring psychedelics have been used for a long time as remedies or in religious ceremonies and recreational activities. Recent studies have proven the therapeutic potential of some psychedelic compounds to safely treat a wide range of diseases such as anxiety, depression, migraine, and addiction. It is hypothesized that psychedelic compounds like tryptamines can exert their effects by two possible mechanisms: binding to the transmembrane serotonin receptor and/or modifying the properties of the neuronal membrane that can alter the conformational equilibrium and desensitize receptors. The impact of three different tryptamine class compounds with a tertiary amine (dimethyltryptamine, bufotenine, and 5-MeO-DMT) in both neutral and charged forms on a model bilayer lipid membrane are studied using all-atom MD simulations. All compounds partition into the bilayer, and change membrane properties, but to different extents. We determine the tendency of compounds to partition into the membrane by free energy calculations. Neutral tryptamines partition into the bilayer almost completely. Dimethyltryptamine and 5-MeO-DMT cross the membrane spontaneously during the simulation time, but bufotenine does not, although it has the maximum effect on the structural properties of the membrane. However, protonated compounds partition partially into the bilayer and cannot pass through the middle of the membrane during the simulation time. In this way, subtle alteration of chemical structure can play a significant role in the improvement or deterioration of partitioning of these compounds into the bilayer and their passage across the membrane.
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Affiliation(s)
- Fateme Zohairi
- Faculty of Science, Technology and Medicine, University of Luxembourg, 2 Av. de l'Universite, 4365 Esch-sur-Alzette, Luxembourg
| | - Himanshu Khandelia
- PHYLIFE: Physical Life Science, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
| | - Ali Asghar Hakami Zanjani
- PHYLIFE: Physical Life Science, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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Nguyen TQT, Lund FW, Zanjani AAH, Khandelia H. Magic mushroom extracts in lipid membranes. Biochim Biophys Acta Biomembr 2022; 1864:183957. [PMID: 35561790 DOI: 10.1016/j.bbamem.2022.183957] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 04/28/2022] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
The active hallucinogen of magic mushrooms, psilocin, is being repurposed to treat nicotine addiction and treatment-resistant depression. Psilocin belongs to the tryptamine class of psychedelic compounds which include the hormone serotonin. It is believed that psilocin exerts its effect by binding to the serotonin 5-HT2A receptor. However, recent in-vivo evidence suggests that psilocin may employ a different mechanism to exert its effects. Membrane-mediated receptor desensitization of neurotransmitter receptors is one such mechanism. We compare the impact of the neutral and charged versions of psilocin and serotonin on the properties of zwitterionic and anionic lipid membranes using molecular dynamics simulations and calorimetry. Both compounds partition to the lipid interface and induce membrane thinning. The tertiary amine in psilocin, as opposed to the primary amine in serotonin, limits psilocin's impact on the membrane although more psilocin partitions into the membrane than serotonin. Calorimetry corroborates that both compounds induce a classical melting point depression like anesthetics do. Our results also lend support to a membrane-mediated receptor-binding mechanism for both psilocin and serotonin and provide physical insights into subtle chemical changes that can alter the membrane-binding of psychedelic compounds.
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Affiliation(s)
- Teresa Quynh Tram Nguyen
- Physical Life Science, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Frederik Wendelboe Lund
- Physical Life Science, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Ali Asghar Hakami Zanjani
- Physical Life Science, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
| | - Himanshu Khandelia
- Physical Life Science, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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Florentsen CD, Kamp-Sonne A, Moreno-Pescador G, Pezeshkian W, Hakami Zanjani AA, Khandelia H, Nylandsted J, Bendix PM. Annexin A4 trimers are recruited by high membrane curvatures in giant plasma membrane vesicles. Soft Matter 2021; 17:308-318. [PMID: 32756654 DOI: 10.1039/d0sm00241k] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The plasma membrane (PM) of eukaryotic cells consists of a crowded environment comprised of a high diversity of proteins in a complex lipid matrix. The lateral organization of membrane proteins in the PM is closely correlated with biological functions such as endocytosis, membrane budding and other processes which involve protein mediated shaping of the membrane into highly curved structures. Annexin A4 (ANXA4) is a prominent player in a number of biological functions including PM repair. Its binding to membranes is activated by Ca2+ influx and it is therefore rapidly recruited to the cell surface near rupture sites where Ca2+ influx takes place. However, the free edges near rupture sites can easily bend into complex curvatures and hence may accelerate recruitment of curvature sensing proteins to facilitate rapid membrane repair. To analyze the curvature sensing behavior of curvature inducing proteins in crowded membranes, we quantifify the affinity of ANXA4 monomers and trimers for high membrane curvatures by extracting membrane nanotubes from giant PM vesicles (GPMVs). ANXA4 is found to be a sensor of negative membrane curvatures. Multiscale simulations, in which we extract molecular information from atomistic scale simulations as input to our macroscopic scale simulations, furthermore predicted that ANXA4 trimers generate membrane curvature upon binding and have an affinity for highly curved membrane regions only within a well defined membrane curvature window. Our results indicate that curvature sensing and mobility of ANXA4 depend on the trimer structure of ANXA4 which could provide new biophysical insight into the role of ANXA4 in membrane repair and other biological processes.
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Affiliation(s)
| | | | | | - Weria Pezeshkian
- Groningen Biomolecular Sciences and Biotechnology, Institute and Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | | | - Himanshu Khandelia
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Denmark
| | - Jesper Nylandsted
- Danish Cancer Society Research Center, Strandboulevarden 49, DK-2100 Copenhagen, Denmark and Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Denmark
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Bendix PM, Simonsen AC, Florentsen CD, Häger SC, Mularski A, Zanjani AAH, Moreno-Pescador G, Klenow MB, Sønder SL, Danielsen HM, Arastoo MR, Heitmann AS, Pandey MP, Lund FW, Dias C, Khandelia H, Nylandsted J. Interdisciplinary Synergy to Reveal Mechanisms of Annexin-Mediated Plasma Membrane Shaping and Repair. Cells 2020; 9:E1029. [PMID: 32326222 PMCID: PMC7226303 DOI: 10.3390/cells9041029] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 04/16/2020] [Accepted: 04/19/2020] [Indexed: 12/22/2022] Open
Abstract
The plasma membrane surrounds every single cell and essentially shapes cell life by separating the interior from the external environment. Thus, maintenance of cell membrane integrity is essential to prevent death caused by disruption of the plasma membrane. To counteract plasma membrane injuries, eukaryotic cells have developed efficient repair tools that depend on Ca2+- and phospholipid-binding annexin proteins. Upon membrane damage, annexin family members are activated by a Ca2+ influx, enabling them to quickly bind at the damaged membrane and facilitate wound healing. Our recent studies, based on interdisciplinary research synergy across molecular cell biology, experimental membrane physics, and computational simulations show that annexins have additional biophysical functions in the repair response besides enabling membrane fusion. Annexins possess different membrane-shaping properties, allowing for a tailored response that involves rapid bending, constriction, and fusion of membrane edges for resealing. Moreover, some annexins have high affinity for highly curved membranes that appear at free edges near rupture sites, a property that might accelerate their recruitment for rapid repair. Here, we discuss the mechanisms of annexin-mediated membrane shaping and curvature sensing in the light of our interdisciplinary approach to study plasma membrane repair.
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Affiliation(s)
- Poul Martin Bendix
- Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark; (C.D.F.); (G.M.-P.); (H.M.D.); (M.R.A.)
| | - Adam Cohen Simonsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense, Denmark; (A.M.); (A.A.H.Z.); (M.B.K.); (M.P.P.); (F.W.L.)
| | - Christoffer D. Florentsen
- Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark; (C.D.F.); (G.M.-P.); (H.M.D.); (M.R.A.)
| | - Swantje Christin Häger
- Membrane Integrity, Cell Death and Metabolism Unit, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, DK-2100 Copenhagen, Denmark; (S.C.H.); (S.L.S.); (A.S.H.); (C.D.)
| | - Anna Mularski
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense, Denmark; (A.M.); (A.A.H.Z.); (M.B.K.); (M.P.P.); (F.W.L.)
| | - Ali Asghar Hakami Zanjani
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense, Denmark; (A.M.); (A.A.H.Z.); (M.B.K.); (M.P.P.); (F.W.L.)
| | - Guillermo Moreno-Pescador
- Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark; (C.D.F.); (G.M.-P.); (H.M.D.); (M.R.A.)
| | - Martin Berg Klenow
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense, Denmark; (A.M.); (A.A.H.Z.); (M.B.K.); (M.P.P.); (F.W.L.)
| | - Stine Lauritzen Sønder
- Membrane Integrity, Cell Death and Metabolism Unit, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, DK-2100 Copenhagen, Denmark; (S.C.H.); (S.L.S.); (A.S.H.); (C.D.)
| | - Helena M. Danielsen
- Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark; (C.D.F.); (G.M.-P.); (H.M.D.); (M.R.A.)
| | - Mohammad Reza Arastoo
- Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark; (C.D.F.); (G.M.-P.); (H.M.D.); (M.R.A.)
| | - Anne Sofie Heitmann
- Membrane Integrity, Cell Death and Metabolism Unit, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, DK-2100 Copenhagen, Denmark; (S.C.H.); (S.L.S.); (A.S.H.); (C.D.)
| | - Mayank Prakash Pandey
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense, Denmark; (A.M.); (A.A.H.Z.); (M.B.K.); (M.P.P.); (F.W.L.)
| | - Frederik Wendelboe Lund
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense, Denmark; (A.M.); (A.A.H.Z.); (M.B.K.); (M.P.P.); (F.W.L.)
| | - Catarina Dias
- Membrane Integrity, Cell Death and Metabolism Unit, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, DK-2100 Copenhagen, Denmark; (S.C.H.); (S.L.S.); (A.S.H.); (C.D.)
| | - Himanshu Khandelia
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense, Denmark; (A.M.); (A.A.H.Z.); (M.B.K.); (M.P.P.); (F.W.L.)
| | - Jesper Nylandsted
- Membrane Integrity, Cell Death and Metabolism Unit, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, DK-2100 Copenhagen, Denmark; (S.C.H.); (S.L.S.); (A.S.H.); (C.D.)
- Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
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Zanjani AAH, Reynolds NP, Zhang A, Schilling T, Mezzenga R, Berryman JT. Kinetic Control of Parallel versus Antiparallel Amyloid Aggregation via Shape of the Growing Aggregate. Sci Rep 2019; 9:15987. [PMID: 31690748 PMCID: PMC6831816 DOI: 10.1038/s41598-019-52238-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/14/2019] [Indexed: 11/09/2022] Open
Abstract
By combining atomistic and higher-level modelling with solution X-ray diffraction we analyse self-assembly pathways for the IFQINS hexapeptide, a bio-relevant amyloid former derived from human lysozyme. We verify that (at least) two metastable polymorphic structures exist for this system which are substantially different at the atomistic scale, and compare the conditions under which they are kinetically accessible. We further examine the higher-level polymorphism for these systems at the nanometre to micrometre scales, which is manifested in kinetic differences and in shape differences between structures instead of or as well as differences in the small-scale contact topology. Any future design of structure based inhibitors of the IFQINS steric zipper, or of close homologues such as TFQINS which are likely to have similar structures, should take account of this polymorphic assembly.
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Affiliation(s)
- Ali Asghar Hakami Zanjani
- University of Luxembourg, Department of Physics and Materials Science, 162a Avenue de la Fäıencerie, Luxembourg City, L-1511, Luxembourg
| | - Nicholas P Reynolds
- Swinburne University of Technology, ARC Training Centre for Biodevices, John Street, Melbourne, VIC, 3122, Australia
| | - Afang Zhang
- Shanghai University Department of Polymer Materials, Nanchen Street 333, Shanghai, 200444, China
| | - Tanja Schilling
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104, Freiburg im Breisgau, Germany
| | - Raffaele Mezzenga
- Department of Health Sciences and Technology, ETH Zurich, CH-8092, Zurich, Switzerland.,Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093, Zurich, Switzerland
| | - Joshua T Berryman
- University of Luxembourg, Department of Physics and Materials Science, 162a Avenue de la Fäıencerie, Luxembourg City, L-1511, Luxembourg.
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Reynolds NP, Adamcik J, Berryman JT, Handschin S, Zanjani AAH, Li W, Liu K, Zhang A, Mezzenga R. Competition between crystal and fibril formation in molecular mutations of amyloidogenic peptides. Nat Commun 2017; 8:1338. [PMID: 29109399 PMCID: PMC5673901 DOI: 10.1038/s41467-017-01424-4] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 09/12/2017] [Indexed: 12/18/2022] Open
Abstract
Amyloidogenic model peptides are invaluable for investigating assembly mechanisms in disease related amyloids and in protein folding. During aggregation, such peptides can undergo bifurcation leading to fibrils or crystals, however the mechanisms of fibril-to-crystal conversion are unclear. We navigate herein the energy landscape of amyloidogenic peptides by studying a homologous series of hexapeptides found in animal, human and disease related proteins. We observe fibril-to-crystal conversion occurring within single aggregates via untwisting of twisted ribbon fibrils possessing saddle-like curvature and cross-sectional aspect ratios approaching unity. Changing sequence, pH or concentration shifts the growth towards larger aspect ratio species assembling into stable helical ribbons possessing mean-curvature. By comparing atomistic calculations of desolvation energies for association of peptides we parameterise a kinetic model, providing a physical explanation of fibril-to-crystal interconversion. These results shed light on the self-assembly of amyloidogenic peptides, suggesting amyloid crystals, not fibrils, represent the ground state of the protein folding energy landscape. Aggregation of amyloidogenic peptides into fibrils and crystals has incidence in several amyloid-related diseases. Here, the authors investigate the origins of the fibril-to-crystal conversion in amyloidogenic hexapeptides pointing to the amyloid crystals as the ground state in the protein folding energy landscape.
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Affiliation(s)
- Nicholas P Reynolds
- Swinburne University of Technology, ARC Training Centre for Biodevices, Faculty of Science, Engineering and Technology, John Street, Melbourne, VIC, 3122, Australia
| | - Jozef Adamcik
- ETH Zurich, Department of Health Sciences & Technology, Schmelzbergstrasse 9, LFO, E23, 8092, Zürich, Switzerland
| | - Joshua T Berryman
- University of Luxembourg, Department of Physics and Materials Science, 162a Avenue de la Faïencerie, Luxembourg City, L-1511, Luxembourg
| | - Stephan Handschin
- ETH Zurich, Department of Health Sciences & Technology, Schmelzbergstrasse 9, LFO, E23, 8092, Zürich, Switzerland
| | - Ali Asghar Hakami Zanjani
- University of Luxembourg, Department of Physics and Materials Science, 162a Avenue de la Faïencerie, Luxembourg City, L-1511, Luxembourg
| | - Wen Li
- Shanghai University, Department of Polymer Materials, Nanchen Street 333, Shanghai, 200444, China
| | - Kun Liu
- Shanghai University, Department of Polymer Materials, Nanchen Street 333, Shanghai, 200444, China
| | - Afang Zhang
- Shanghai University, Department of Polymer Materials, Nanchen Street 333, Shanghai, 200444, China
| | - Raffaele Mezzenga
- ETH Zurich, Department of Health Sciences & Technology, Schmelzbergstrasse 9, LFO, E23, 8092, Zürich, Switzerland. .,ETH Zurich, Department of Materials, Wolfgang-Pauli-Strasse 10, 8093, Zurich, Switzerland.
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