PROMIX · Cluster, glass, and crystal formation in concentrated protein mixtures of opposite charge sign
FP7 — People (Marie Curie Actions)
- Duration
- 2009-03-01 → 2011-02-28
- EU contribution
- €180,801
- Participants
- 1
- Scheme
- MC-IEF
Lines connect the coordinator with its partners.
Results in brief
Cluster, glass, and crystal formation in concentrated protein mixtures of opposite charge sign
Phase separation and crystallization Concentrated protein mixtures are ubiquitous in nature and widespread in many fields of technology. For example, living cells contain up to 300 mg ml-1 of thousands of different proteins in their intracellular fluid. An interesting new development in the food sciences concerns "high protein foods". These products contain large amounts of proteins and are thought to aid in the fight against obesitas and perhaps sarcopenia. While each organism or application may require a specific set of components and circumstances to function properly, perform optimally, or taste exquisitely, they certainly share one common requirement: stability. It is one of the biggest challenges in the field, as concentrated protein mixtures are prone to undergo many different types of phase transitions, such as crystallization, liquid-liquid phase separation, and complex coacervation (Figure 1). The physico-chemical approach Within the framework of PROMIX, we have used a combination of experimental methods, including UV-Vis spectroscopy, confocal laser scanning microscopy, X-ray scattering, and optical microscopy to systematically investigate the phase behaviour of several concentrated binary protein mixtures. Our experiments revealed how the salt concentration, pH, and protein composition essentially dictate the phase state (liquid, solid, order, disorder) of the system. Furthermore, our findings strongly suggest that stability in more complex protein mixtures, such as intracellular fluids (also known as the cytosol), is governed by counter-ion entropy and partial protein volume fractions rather than by protein specific properties. This opens new pathways for a thermodynamic description of protein mixtures that may account for their extraordinary stability encountered in nature. We therefore hope to connect our experimental results in the near future to a theoretical framework to further enhance our understanding of the physics behind the rich and fascinating phase behaviour of concentrated protein mixtures.
Data: CORDIS, © European Union
Project objective
Protein mixtures are essential ingredients in a multitude of natural and synthetic complex systems, such as the eye lens, the blood stream, the cytoplasm of living cells, yoghurt, and so forth. Research on protein interactions is thus pivotal to gain insight in the stability of such soft matter systems, in their structural and dynamical properties, and in their (biological) function. As nearly all of the current work focuses on interactions in relatively simple model systems (i.e., mixtures of either identical or like-charged proteins), this project will deal with cluster, glass, and crystal formation in concentrated protein mixtures of opposite charge. The project is highly original and proposed at an ideal time in the development of the field. In spite of considerable community interest, no systematic study, using (recently developed) suitable instrumental techniques and in close alliance with several European scientists who develop theory and simulations of the model systems, has been undertaken. This provides the community with a unique opportunity to link an excellent female researcher (MSc and PhD degrees were awarded cum laude) with an ideal background and proven ability to collaborate with an institution that has made major strides in this area of emerging interest and can provide the applicant with the necessary infrastructure and expertise to make this project work. As outlined in the following, the IEF fellowship will allow the applicant to gain additional scientific competencies and skills, to consolidate and extend her presentation and language skills, and to acquire additional and complementary management and leadership competencies and skills. Hence, this project will have a significant impact on the applicant’s future career prospects who is aiming to reach a position of professional maturity, diversity, and independence as her long-term goal is to establish an independent line of research within Europe in the field of life sciences.
Original text from CORDIS.
Participants
- UNIVERSITE DE FRIBOURG · FribourgCoordinatorSwitzerland
Links
Data: CORDIS, © European Union