Abstract
Liquid–liquid phase separation of disordered proteins has emerged as a ubiquitous route to membraneless compartments in living cells, and similar coacervates may have played a role when the first cells formed. However, existing coacervates are typically made of multiple macromolecular components, and designing short peptide analogues capable of self-coacervation has proven difficult. Here we present a short peptide synthon for phase separation, made of only two dipeptide stickers linked via a flexible, hydrophilic spacer. These small-molecule compounds self-coacervate into micrometre-sized liquid droplets at sub-millimolar concentrations, which retain up to 75 wt% water. The design is general and we derive guidelines for the required sticker hydrophobicity and spacer polarity. To illustrate their potential as protocells, we create a disulfide-linked derivative that undergoes reversible compartmentalization controlled by redox chemistry. The resulting coacervates sequester and melt nucleic acids, and act as microreactors that catalyse two different anabolic reactions yielding molecules of increasing complexity. This provides a stepping stone for new coacervate-based protocells made of single peptide species.

This is a preview of subscription content, access via your institution
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout




Similar content being viewed by others
Data availability
All data supporting the findings of this study are available within the article and in the Supplementary Information and Data files. Source data are provided with this paper.
References
Koshland, D. E. Jr. Special essay: The seven pillars of life. Science 295, 2215–2216 (2002).
Yewdall, N. A., Mason, A. F. & van Hest, J. C. M. The hallmarks of living systems: towards creating artificial cells. Interface Focus 8, 20180023 (2018).
Mann, S. Systems of creation: the emergence of life from nonliving matter. Acc. Chem. Res. 45, 2131–2141 (2012).
Cronin, L. & Walker, S. I. Beyond prebiotic chemistry. Science 352, 1174–1175 (2016).
Dzieciol, A. J. & Mann, S. Designs for life: protocell models in the laboratory. Chem. Soc. Rev. 41, 79–85 (2012).
Poudyal, R. R., Pir Cakmak, F., Keating, C. D. & Bevilacqua, P. C. Physical principles and extant biology reveal roles for RNA-containing membraneless compartments in origins of life chemistry. Biochemistry 57, 2509–2519 (2018).
Toparlak, O. D. & Mansy, S. S. Progress in synthesizing protocells. Exp. Biol. Med. 244, 304–313 (2019).
Kurihara, K. et al. A recursive vesicle-based model protocell with a primitive model cell cycle. Nat. Commun. 6, 8352 (2015).
Blain, J. C. & Szostak, J. W. Progress toward synthetic cells. Annu. Rev. Biochem. 83, 615–640 (2014).
Hanczyc, M. M., Fujikawa, S. M. & Szostak, J. W. Experimental models of primitive cellular compartments: encapsulation, growth, and division. Science 302, 618–622 (2003).
Vogele, K. et al. Towards synthetic cells using peptide-based reaction compartments. Nat. Commun. 9, 3862 (2018).
Schreiber, A., Huber, M. C. & Schiller, S. M. Prebiotic protocell model based on dynamic protein membranes accommodating anabolic reactions. Langmuir 35, 9593–9610 (2019).
Rahman, Md. M., Ueda, M., Hirose, T. & Ito, Y. Spontaneous formation of gating lipid domain in uniform-size peptide vesicles for controlled release. J. Am. Chem. Soc. 140, 17956–17961 (2018).
Monnard, P.-A. & Deamer, D. W. Membrane self-assembly processes: steps toward the first cellular life. Anat. Rec. 268, 196–207 (2002).
Litschel, T. et al. Freeze–thaw cycles induce content exchange between cell-sized lipid vesicles. New J. Phys. 20, 055008 (2018).
Koga, S., Williams, D. S., Perriman, A. W. & Mann, S. Peptide–nucleotide microdroplets as a step towards a membrane-free protocell model. Nat. Chem. 3, 720–724 (2011).
Abbas, M., Lipiński, W. P., Wang, J. & Spruijt, E. Peptide-based coacervates as biomimetic protocells. Chem. Soc. Rev. 50, 3690–3705 (2021).
Drobot, B. et al. Compartmentalised RNA catalysis in membrane-free coacervate protocells. Nat. Commun. 9, 3643 (2018).
Poudyal, R. R. et al. Template-directed RNA polymerization and enhanced ribozyme catalysis inside membraneless compartments formed by coacervates. Nat. Commun. 10, 490 (2019).
Nakashima, K. K., Baaij, J. F. & Spruijt, E. Reversible generation of coacervate droplets in an enzymatic network. Soft Matter 14, 361–367 (2018).
Love, C. et al. Reversible pH‐responsive coacervate formation in lipid vesicles activates dormant enzymatic reactions. Angew. Chem. Int. Ed. 59, 5950–5957 (2020).
Boeynaems, S. et al. Protein phase separation: a new phase in cell biology. Trends Cell Biol. 28, 420–435 (2018).
Shin, Y. & Brangwynne, C. P. Liquid phase condensation in cell physiology and disease. Science 357, eaaf4382 (2017).
Banani, S. F., Lee, H. O., Hyman, A. A. & Rosen, M. K. Biomolecular condensates: organizers of cellular biochemistry. Nat. Rev. Mol. Cell Biol. 18, 285–298 (2017).
Yin, Y. et al. Non-equilibrium behaviour in coacervate-based protocells under electric-field-induced excitation. Nat. Commun. 7, 10658 (2016).
Perry, S. L. et al. Chirality-selected phase behaviour in ionic polypeptide complexes. Nat. Commun. 6, 1–8 (2015).
Aumiller, W. M. & Keating, C. D. Phosphorylation-mediated RNA/peptide complex coacervation as a model for intracellular liquid organelles. Nat. Chem. 8, 129–137 (2016).
Madinya, J. J., Chang, L.-W., Perry, S. L. & Sing, C. E. Sequence-dependent self-coacervation in high charge-density polyampholytes. Mol. Syst. Des. Eng. 5, 632–644 (2020).
Simon, J. R., Carroll, N. J., Rubinstein, M., Chilkoti, A. & López, G. P. Programming molecular self-assembly of intrinsically disordered proteins containing sequences of low complexity. Nat. Chem. 9, 509–515 (2017).
Murthy, A. C. et al. Molecular interactions underlying liquid–liquid phase separation of the FUS low-complexity domain. Nat. Struct. Mol. Biol. 26, 637–648 (2019).
Martin, E. W. et al. Valence and patterning of aromatic residues determine the phase behavior of prion-like domains. Science 367, 694–699 (2020).
Gomes, E. & Shorter, J. The molecular language of membraneless organelles. J. Biol. Chem. 294, 7115–7127 (2019).
Wang, J. et al. A molecular grammar governing the driving forces for phase separation of prion-like RNA binding proteins. Cell 174, 688–699.e16 (2018).
Choi, J.-M., Holehouse, A. S. & Pappu, R. V. Physical principles underlying the complex biology of intracellular phase transitions. Annu. Rev. Biophys. 49, 107–133 (2020).
Reches, M. & Gazit, E. Formation of closed-cage nanostructures by self-assembly of aromatic dipeptides. Nano Lett. 4, 581–585 (2004).
Adler-Abramovich, L. & Gazit, E. The physical properties of supramolecular peptide assemblies: from building block association to technological applications. Chem. Soc. Rev. 43, 6881–6893 (2014).
Chen, C., Liu, K., Li, J. & Yan, X. Functional architectures based on self-assembly of bio-inspired dipeptides: structure modulation and its photoelectronic applications. Adv. Colloid Interface Sci. 225, 177–193 (2015).
Yuan, C. et al. Nucleation and growth of amino acid and peptide supramolecular polymers through liquid–liquid phase separation. Angew. Chem. Int. Ed. 58, 18116–18123 (2019).
Brady, J. P. et al. Structural and hydrodynamic properties of an intrinsically disordered region of a germ cell-specific protein on phase separation. Proc. Natl Acad. Sci. USA 114, E8194–E8203 (2017).
Sprakel, J., Besseling, N. A. M., Cohen Stuart, M. A. & Leermakers, F. A. M. Phase behavior of flowerlike micelles in a SCF cell model. Eur. Phys. J. E 25, 163–173 (2008).
Srivastava, S. et al. Gel phase formation in dilute triblock copolyelectrolyte complexes. Nat. Commun. 8, 14131 (2017).
Zhang, X., Malhotra, S., Molina, M. & Haag, R. Micro- and nanogels with labile crosslinks—from synthesis to biomedical applications. Chem. Soc. Rev. 44, 1948–1973 (2015).
Bungenberg de Jong, H. G. & Kruyt, H. R. Coacervation (partial miscibility in colloid systems). Proc. Neth. Acad. Sci. 32, 849–856 (1929).
Schuster, B. S. et al. Identifying sequence perturbations to an intrinsically disordered protein that determine its phase-separation behavior. Proc. Natl Acad. Sci. USA 117, 11421–11431 (2020).
Zhang, H. et al. RNA controls polyQ protein phase transitions. Mol. Cell 60, 220–230 (2015).
Kaminker, I. et al. Simple peptide coacervates adapted for rapid pressure-sensitive wet adhesion. Soft Matter 13, 9122–9131 (2017).
André, A. A. M. & Spruijt, E. Liquid–liquid phase separation in crowded environments. Int. J. Mol. Sci. 21, 5908 (2020).
Shen, Y. et al. Biomolecular condensates undergo a generic shear-mediated liquid-to-solid transition. Nat. Nanotechnol. 15, 841–847 (2020).
Gutierrez, J. M. P., Hinkley, T., Taylor, J. W., Yanev, K. & Cronin, L. Evolution of oil droplets in a chemorobotic platform. Nat. Commun. 5, ncomms6571 (2014).
Tena-Solsona, M., Wanzke, C., Riess, B., Bausch, A. R. & Boekhoven, J. Self-selection of dissipative assemblies driven by primitive chemical reaction networks. Nat. Commun. 9, 2044 (2018).
Cashman, T. J. & Linton, B. R. β-Sheet hydrogen bonding patterns in cystine peptides. Org. Lett. 9, 5457–5460 (2007).
Bogunia, M. & Makowski, M. Influence of ionic strength on hydrophobic interactions in water: dependence on solute size and shape. J. Phys. Chem. B 124, 10326–10336 (2020).
Biancalana, M., Makabe, K., Koide, A. & Koide, S. Molecular mechanism of thioflavin-T binding to the surface of β-rich peptide self-assemblies. J. Mol. Biol. 385, 1052–1063 (2009).
Zhao, M. et al. Partitioning of small molecules in hydrogen-bonding complex coacervates of poly(acrylic acid) and poly(ethylene glycol) or pluronic block copolymer. Macromolecules 50, 3818–3830 (2017).
Nott, T. J., Craggs, T. D. & Baldwin, A. J. Membraneless organelles can melt nucleic acid duplexes and act as biomolecular filters. Nat. Chem. 8, 569–575 (2016).
Cakmak, F. P., Choi, S., Meyer, M. O., Bevilacqua, P. C. & Keating, C. D. Prebiotically-relevant low polyion multivalency can improve functionality of membraneless compartments. Nat. Commun. 11, 5949 (2020).
Vieregg, J. R. et al. Oligonucleotide–peptide complexes: phase control by hybridization. J. Am. Chem. Soc. 140, 1632–1638 (2018).
Sokolova, E. et al. Enhanced transcription rates in membrane-free protocells formed by coacervation of cell lysate. Proc. Natl Acad. Sci. USA 110, 11692–11697 (2013).
Luppi, G. et al. Dipeptide-catalyzed asymmetric aldol condensation of acetone with (N-alkylated) isatins. J. Org. Chem. 70, 7418–7421 (2005).
Springsteen, G., Yerabolu, J. R., Nelson, J., Rhea, C. J. & Krishnamurthy, R. Linked cycles of oxidative decarboxylation of glyoxylate as protometabolic analogs of the citric acid cycle. Nat. Commun. 9, 91 (2018).
Huerta, E., van Genabeek, B., Stals, P. J. M., Meijer, E. W. & Palmans, A. R. A. A modular approach to introduce function into single-chain polymeric nanoparticles. Macromol. Rapid Commun. 35, 1320–1325 (2014).
Dirksen, A., Dirksen, S., Hackeng, T. M. & Dawson, P. E. Nucleophilic catalysis of hydrazone formation and transimination: implications for dynamic covalent chemistry. J. Am. Chem. Soc. 128, 15602–15603 (2006).
Li, J. et al. Determination of residual phenylhydrazines in drug substances by high-performance liquid chromatography with pre-column derivatization. Anal. Methods 11, 6146–6152 (2019).
Frederix, P. W. J. M. et al. Exploring the sequence space for (tri-)peptide self-assembly to design and discover new hydrogels. Nat. Chem. 7, 30–37 (2015).
Serrano-Luginbühl, S., Ruiz-Mirazo, K., Ostaszewski, R., Gallou, F. & Walde, P. Soft and dispersed interface-rich aqueous systems that promote and guide chemical reactions. Nat. Rev. Chem. 2, 306–327 (2018).
Acknowledgements
This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme under grant agreement number 851963, and from the Netherlands Organization for Scientific Research (NWO-Startup to E.S.). M.A. gratefully acknowledges a Marie Skłodowska Curie Individual Fellowship (project number 839177).
Author information
Authors and Affiliations
Contributions
M.A. and E.S. conceived the idea and designed the experiments. M.A. and W.P.L. synthesized the peptide derivatives and performed their analysis. M.A. performed redox, microscopy and microreactor experiments. K.K.N. performed microscopy experiments with FFssFF. All authors discussed the results and interpreted data. M.A., E.S. and W.T.S.H. wrote the manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Peer review information Nature Chemistry thanks Samrat Mukhopadhyay and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary information
Supplementary Information
Supplementary materials and methods 1 and 2, Figs. 1–28, discussion and Table 1.
Source data
Source Data Fig. 1
Unprocessed images, Source data points
Source Data Fig. 2
Unprocessed images, Source data points
Source Data Fig. 3
Unprocessed images
Source Data Fig. 4
Source data points and fits
Rights and permissions
About this article
Cite this article
Abbas, M., Lipiński, W.P., Nakashima, K.K. et al. A short peptide synthon for liquid–liquid phase separation. Nat. Chem. 13, 1046–1054 (2021). https://doi.org/10.1038/s41557-021-00788-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41557-021-00788-x
This article is cited by
-
Biomolecular condensates formed by designer minimalistic peptides
Nature Communications (2023)
-
Engineering synthetic biomolecular condensates
Nature Reviews Bioengineering (2023)
-
The molecular basis for cellular function of intrinsically disordered protein regions
Nature Reviews Molecular Cell Biology (2023)
-
Open questions on liquid–liquid phase separation
Communications Chemistry (2023)
-
Peptide-based liquid droplets as emerging delivery vehicles
Nature Reviews Materials (2023)