Coacervate

Coacervate droplets dispersed in a dilute phase

Coacervate (/koʊəˈsɜːrvət/ or /koʊˈæsərveɪt/) is an aqueous phase rich in macromolecules such as synthetic polymers, proteins or nucleic acids. It forms through liquid-liquid phase separation (LLPS), leading to a dense phase in thermodynamic equilibrium with a dilute phase. The dispersed droplets of dense phase are also called coacervates, micro-coacervates or coacervate droplets. These structures draw a lot of interest because they form spontaneously from aqueous mixtures and provide stable compartmentalization without the need of a membrane—they are protocell candidates.

The term coacervate was coined in 1929 by Dutch chemist Hendrik G. Bungenberg de Jong and Hugo R. Kruyt while studying lyophilic colloidal dispersions.[1] The name is a reference to the clustering of colloidal particles, like bees in a swarm. The concept was later borrowed by Russian biologist Alexander I. Oparin to describe the proteinoid microspheres proposed to be primitive cells (protocells) on early Earth.[2] Coacervate-like protocells are at the core of the Oparin-Haldane hypothesis.

A reawakening of coacervate research was seen in the 2000s, starting with the recognition in 2004 by scientists at the University of California, Santa Barbara (UCSB) that some marine invertebrates (such as the sandcastle worm) exploit complex coacervation to produce water-resistant biological adhesives.[3][4] A few years later in 2009 the role of liquid-liquid phase separation was further recognized to be involved in the formation of certain membraneless organelles by the biophysicists Clifford Brangwynne and Tony Hyman.[5] Liquid organelles share features with coacervate droplets and fueled the study of coacervates for biomimicry.[6][7]

  1. ^ Booij, H. L.; Bungenberg de Jong, H. G. (1956), "Colloid Systems", Biocolloids and their Interactions, Vienna: Springer Vienna, pp. 8–14, doi:10.1007/978-3-7091-5456-4_2, ISBN 978-3-211-80421-6
  2. ^ Oparin, Aleksandr Ivanovich; Synge, Ann. (1957). The origin of life on the earth / Translated from the Russian by Ann Synge. New York: Academic Press. doi:10.5962/bhl.title.4528.
  3. ^ Stewart, R.J.; Weaver, J.C.; Morse, D.E.; Waite, J.H (2004). "The Tube Cement of Phragmatopoma californica: a solid foam". The Journal of Experimental Biology. 207 (26): 4727–34. doi:10.1242/jeb.01330. PMID 15579565. S2CID 1104838.
  4. ^ Zhao, H.; Sun, C.; Stewart, R.J.; Waite, J.H. (2005). "Cement Proteins of the Tube-Building Polychaete Phragmatopoma californica". The Journal of Biological Chemistry. 280 (52): 42938–44. doi:10.1074/jbc.M508457200. PMID 16227622. S2CID 7746883.
  5. ^ Brangwynne, C. P.; Eckmann, C. R.; Courson, D. S.; Rybarska, A.; Hoege, C.; Gharakhani, J.; Julicher, F.; Hyman, A. A. (2009-06-26). "Germline P Granules Are Liquid Droplets That Localize by Controlled Dissolution/Condensation". Science. 324 (5935): 1729–1732. Bibcode:2009Sci...324.1729B. doi:10.1126/science.1172046. ISSN 0036-8075. PMID 19460965. S2CID 42229928.
  6. ^ Nakashima, Karina K.; Vibhute, Mahesh A.; Spruijt, Evan (2019-04-03). "Biomolecular Chemistry in Liquid Phase Separated Compartments". Frontiers in Molecular Biosciences. 6: 21. doi:10.3389/fmolb.2019.00021. ISSN 2296-889X. PMC 6456709. PMID 31001538.
  7. ^ Aumiller, William M.; Pir Cakmak, Fatma; Davis, Bradley W.; Keating, Christine D. (2016-10-04). "RNA-Based Coacervates as a Model for Membraneless Organelles: Formation, Properties, and Interfacial Liposome Assembly". Langmuir. 32 (39): 10042–10053. doi:10.1021/acs.langmuir.6b02499. ISSN 0743-7463. PMID 27599198.