Skip to main content

α-Synuclein’s Uniquely Long Amphipathic Helix Enhances its Membrane Binding and Remodeling Capacity

A Correction to this article was published on 27 July 2018

This article has been updated


α-Synuclein is the primary protein found in Lewy bodies, the protein and lipid aggregates associated with Parkinson’s disease and Lewy body dementia. The protein folds into a uniquely long amphipathic α-helix (AH) when bound to a membrane, and at high enough concentrations, it induces large-scale remodeling of membranes (tubulation and vesiculation). By engineering a less hydrophobic variant of α-Synuclein, we previously showed that the energy associated with binding of α-Synuclein’s AH correlates with the extent of membrane remodeling (Braun et al. in J Am Chem Soc 136:9962–9972, 2014). In this study, we combine fluorescence correlation spectroscopy, electron microscopy, and vesicle clearance assays with coarse-grained molecular dynamics simulations to test the impact of decreasing the length of the amphipathic helix on membrane binding energy and tubulation. We show that truncation of α-Synuclein’s AH length by approximately 15% reduces both its membrane binding affinity (by fivefold) and membrane remodeling capacity (by nearly 50% on per mole of bound protein basis). Results from simulations correlate well with the experiments and lend support to the idea that at high protein density there is a stabilization of individual, protein-induced membrane curvature fields. The extent to which these curvature fields are stabilized, a function of binding energy, dictates the extent of tubulation. Somewhat surprisingly, we find that this stabilization does not correlate directly with the geometric distribution of the proteins on the membrane surface.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5

Change history

  • 27 July 2018

    The original version of the article unfortunately contained error in author group; two authors were not submitted and published in the original version. Also the funding information is erroneously omitted.


  1. Braun AR, Brandt EG, Edholm O, Nagle JF, Sachs JN (2011) Determination of electron density profiles and area from simulations of undulating membranes. Biophys J 100:2112–2120

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  2. Braun AR, Sevcsik E, Chin P, Rhoades E, Tristram-Nagle S, Sachs JN (2012) Alpha-Synuclein induces both positive mean curvature and negative Gaussian curvature in membranes. J Am Chem Soc 134:2613–2620

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  3. Braun AR, Lacy MM, Ducas VC, Rhoades E, Sachs JN (2014) a-Synuclein-induced membrane remodeling is driven by binding affinity, partition depth, and interleaflet order asymmetry. J Am Chem Soc 136:9962–9972

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  4. Chen P, Toribara T, Warner H (1956) Microdetermination of phosphorus. Anal Chem 28:1756–1758

    Article  CAS  Google Scholar 

  5. Cheng CY, Varkey J, Ambroso MR, Langen R, Han S (2013) Hydration dynamics as an intrinsic ruler for refining protein structure at lipid membrane interfaces. Proc Natl Acad Sci USA 110:16838–16843

    Article  PubMed  CAS  Google Scholar 

  6. Cornell RB, Taneva SG (2006) Amphipathic helices as mediators of the membrane interaction of amphitropic proteins, and as modulators of bilayer physical properties. Curr Protein Pept Sci 7:539–552

    Article  PubMed  CAS  Google Scholar 

  7. Crowet JM, Lins L, Dupiereux I, Elmoualija B, Lorin A, Charloteaux B, Stroobant V, Heinen E, Brasseur R (2007) Tilted properties of the 67–78 fragment of alpha-synuclein are responsible for membrane destabilization and neurotoxicity. Proteins 68:936–947

    Article  PubMed  CAS  Google Scholar 

  8. de Jong DH, Singh G, Bennett WFD, Arnarez C, Wassenaar TA, Schäfer LV, Periole X, Tieleman DP, Marrink SJ (2013) Improved parameters for the martini coarse-grained protein force field. J Chem Theory Comput 9:687–697

    Article  PubMed  CAS  Google Scholar 

  9. Ducas VC, Rhoades E (2012) Quantifying interactions of b-synuclein and g-synuclein with model membranes. J Mol Biol 423:528–539

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  10. Ducas VC, Rhoades E (2014) Investigation of intramolecular dynamics and conformations of a-, b- and g-synuclein. PLoS One 9:e86983

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  11. Eliezer D (2006) Secondary structure and dynamics of micelle bound b- and g-synuclein. 15:1162–1174

  12. Fusco G, De Simone A, Gopinath T, Vostrikov V, Vendruscolo M, Dobson CM, Veglia G (2014) Direct observation of the three regions in a-synuclein that determine its membrane-bound behaviour. Nat Commun 5:3827

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  13. George JM, Jin H, Woods WS, Clayton DF (1995) Characterization of a novel protein regulated during the critical period for song learning in the zebra finch. Neuron 15:361–372

    Article  PubMed  CAS  Google Scholar 

  14. Hess B, Kutzner C, van der Spoel D, Lindahl E (2008) GROMACS 4: algorithms for highly efficient, load-balanced, and scalable molecular simulation. J Chem Theory Comput 4:435–447

    Article  PubMed  CAS  Google Scholar 

  15. Jao CC, Hegde BG, Chen J, Haworth IS, Langen R (2008) Structure of membrane-bound alpha-synuclein from site-directed spin labeling and computational refinement. Proc Natl Acad Sci USA 105:19666–19671

    Article  PubMed  Google Scholar 

  16. Jiang Z, de Messieres M, Lee JC (2013) Membrane remodeling by alpha-synuclein and effects on amyloid formation. J Am Chem Soc 135:15970–15973

    Article  PubMed  CAS  Google Scholar 

  17. Kamp F, Exner N, Lutz AK, Wender N, Hegermann J, Brunner B, Nuscher B, Bartels T, Giese A, Beyer K, Eimer S, Winklhofer KF, Haass C (2010) Inhibition of mitochondrial fusion by alpha-synuclein is rescued by PINK1, Parkin and DJ-1. EMBO J 29:3571–3589

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  18. Maltsev AS, Chen J, Levine RL, Bax A (2013) Site-specific interaction between alpha-synuclein and membranes probed by NMR-observed methionine oxidation rates. J Am Chem Soc 135:2943–2946

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  19. Marrink SJ, Risselada HJ, Yefimov S, Tieleman DP, de Vries AH (2007) The MARTINI force field: coarse grained model for biomolecular simulations. J Phys Chem B 111:7812–7824

    Article  PubMed  CAS  Google Scholar 

  20. Michaud-Agrawal N, Denning EJ, Woolf TB, Beckstein O (2011) MDAnalysis: a toolkit for the analysis of molecular dynamics simulations. J Comput Chem 32:2327

    Article  CAS  Google Scholar 

  21. Middleton ER, Rhoades E (2010) Effects of curvature and composition on alpha-synuclein binding to lipid vesicles. Biophys J 99:2279–2288

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  22. Monticelli L, Kandasamv SK, Periole X, Larson RG, Tieleman DP, Marrink SJ (2008) The MARTINI coarse-grained force field: extension to proteins. J Chem Theory Comput 4:834

    Article  CAS  Google Scholar 

  23. Nakamura K (2013) Alpha-Synuclein and mitochondria: partners in crime? Neurother 10:391–399

    Article  CAS  Google Scholar 

  24. Nosé S, Klein ML (1983) Constant pressure molecular dynamics for molecular systems. Mol Phys 50:1055–1076

    Article  Google Scholar 

  25. Parrinello M, Rahman A (1981) Polymorphic transitions in single crystals: a new molecular dynamics method. J Appl Phys 52:7182–7190

    Article  CAS  Google Scholar 

  26. Perlmutter JD, Braun AR, Sachs JN (2009) Curvature dynamics of alpha-synuclein familial Parkinson disease mutants: molecular simulations of the micelle- and bilayer-bound forms. J Biol Chem 284:7177–7189

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  27. Simunovic M, Srivastava A, Voth GA (2013) Linear aggregation of proteins on the membrane as a prelude to membrane remodeling. Proc Natl Acad Sci USA 110:20396–20401

    Article  PubMed  CAS  Google Scholar 

  28. Van der Spoel D, Lindahl E, Hess B, Groenhof G, Mark AE, Berendsen HJC (2005) GROMACS: Fast, flexible, and free. J Comput Chem 26:1701–1718

    Article  CAS  Google Scholar 

  29. Trexler AJ, Rhoades E (2009) Alpha-synuclein binds large unilamellar vesicles as an extended helix. BioChemistry 48:2304–2306

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  30. Ulmer TS, Bax A (2005) Comparison of structure and dynamics of micelle-bound human alpha-synuclein and Parkinson disease variants. J Biol Chem 280:43179–43187

    Article  PubMed  CAS  Google Scholar 

  31. Uversky VN, Li J, Souillac P, Millett IS, Doniach S, Jakes R, Goedert M, Fink AL (2002) Biophysical properties of the synucleins and their propensities to fibrillate: inhibition of alpha-synuclein assembly by beta- and gamma-synucleins. J Biol Chem 277:11970–11978

    Article  PubMed  CAS  Google Scholar 

  32. Varkey J, Isas JM, Mizuno N, Jensen MB, Bhatia VK, Jao CC, Petrlova J, Voss JC, Stamou DG, Steven AC, Langen R (2010) Membrane curvature induction and tubulation are common features of synucleins and apolipoproteins. J Biol Chem 285:32486–32493

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  33. West A, Brummel BE, Braun AR, Rhoades E, Sachs JN (2015) Membrane remodeling and mechanics: experiments and simulations of α-Synuclein. Biochim Biophys Acta Biomembr 1858(7):1609

    Google Scholar 

Download references


All simulations and analysis were completed at the Minnesota Supercomputing Institute (MSI). This work was supported in part by the National Institutes of Health R01 NS084998 (to JNS) and NRSA Fellowship F31 NS077634 (to ARB), in addition to GM102815 (to ER) and predoctoral training grant GM008283 (to VCD and MML). No competing financial interests have been declared.

Author Contributions

The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript.

Author information



Corresponding author

Correspondence to Jonathan N. Sachs.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary material 1 (DOCX 204 KB)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Braun, A.R., Lacy, M.M., Ducas, V.C. et al. α-Synuclein’s Uniquely Long Amphipathic Helix Enhances its Membrane Binding and Remodeling Capacity. J Membrane Biol 250, 183–193 (2017).

Download citation


  • Alpha-Synuclein
  • Membrane remodeling
  • Tubulation