Skip navigation
Please use this identifier to cite or link to this item:
Authors: He, Guanhua
Advisors: JonikasWingreen, MartinNed
Contributors: Molecular Biology Department
Subjects: Molecular biology
Issue Date: 2022
Publisher: Princeton, NJ : Princeton University
Abstract: How living cells regulate biomolecular phase separation into a condensed and a dilute phase remains a central question. While most studies have focused on the condensed phase, relatively little is known about the dilute phase. Theoretical studies have suggested that phase separation can be impacted by the formation of stable complexes in the dilute phase of two- component phase-separating systems; however, the existence of such complexes has not been interrogated experimentally. Here we show that such heterocomplexes exist in the dilute phase, using an in vitro reconstitution system of a phase-separated organelle, the pyrenoid, from the model alga Chlamydomonas reinhardtii. The reconstitution system consists of two highly abundant pyrenoid proteins, the CO2-fixing enzyme Rubisco and its linker protein EPYC1. We use fluorescence correlation spectroscopy to measure the dilute-phase diffusion coefficients of these proteins, distinguishing between bound and unbound states. We find that protein complexes consisting of Rubisco and EPYC1 form in the dilute phase with or without condensates present. The majority of these complexes contain one Rubisco molecule, and the fraction of dilute-phase EPYC1 in complex with Rubisco depends on the overall Rubisco:EPYC1 concentration ratio. A minimal model agrees with the measured phase diagram and supports the existence of these Rubisco:EPYC1 complexes. Our results demonstrate the existence of protein oligomers in the dilute phase, which could play a significant role in the dynamics and regulation of condensate assembly.
Alternate format: The Mudd Manuscript Library retains one bound copy of each dissertation. Search for these copies in the library's main catalog:
Type of Material: Academic dissertations (Ph.D.)
Language: en
Appears in Collections:Molecular Biology

Files in This Item:
This content is embargoed until 2024-09-30. For questions about theses and dissertations, please contact the Mudd Manuscript Library. For questions about research datasets, as well as other inquiries, please contact the DataSpace curators.

Items in Dataspace are protected by copyright, with all rights reserved, unless otherwise indicated.